Converting crankset from 28-38-48 to 30-39-53

You will need to purchase only 4 items to accomplish this swap:

Crankset - Standard road triple
Flat bar road shifter set ST-443
FD-443 front derailleur
Possibly new cables, if they don't come with the shifters.
A new chain designed for the number of gears in your cassette.

You will also need to ensure that you've enough adjustment range on the frame to move your front derailleur up by up to 2cm, and that the derailleur you purchase is dual pull, so that you don't need a pull converter.

But it seems to me you've already worked that out.


Help me fix a loose pedal-arm on a fixie!

What is a possible fix for this problem?

Loctite.  Blue.
I have an FSA-based SRM power meter where the self-extracting crank bolt simply will not stay properly torqued without using Loctite.  That's probably pretty similar to the problems you're having. And I'm not backpedaling or skidding with that bike...
I bought the SRM crankset used, so maybe it was ridden with a loose bolt and the crankarm/spindle interface was damaged/distorted prior to my purchasing it, similar to what happens with a square-taper crankset.
I replaced the self-extracting bolt, and that didn't help.
But using blue Loctite works for me.
If that doesn't work for you, you might have to replace your crankset.
I don't recommend red Loctite...


Removing surface rust from my Eggbeater pedals?

You're probably best with a metal brush the consistency of the items recommnded in the question below. Ultimately it's gonna happen though so all we can do is our best to dry up and clean up items. At some point they need replacing. A bit of light oil on the pedal the night before a wet ride might help keep of the rust by not letting water in. Of course it will attract dirt (hence the night before recommend so it dries).

Dealing with rust on a steel frame


Any 6/7 speed Tourney derailleur will be compatible with your shifter, i.e., it will index on a sprocket correctly for each shifter click.

Whatever Tourney model you get you want to make sure it can handle the largest rear sprocket you have and the total capacity which is the difference of tooth counts between smallest and largest sprockets plus  difference of tooth counts between smallest and largest chainrings. Longer cage derailleurs have larger total capacity because they can take up more chain slack.

Specs on the RD-TY500 SGS are here.


Where can I get a fork that will fit a 7 speed gear and a disc brake? Or how could I make one for said specification?

If you are looking to re-purpose off the shelf components: Fat bike forks use dropout spacings of 135mm and 150mm, I believe. Road disc brake bikes and some mountain bikes use 135mm rear spacing, so you should be able to combine a fat bike fork and road rear disc hub. A 135mm rear hub will have space for an 11 speed cassette, but you can use spacers to fit a  7 speed cassette.

If you are building a front wheel drive recumbent, you'll have to at least do some fabricating for the frame attached to the fork that holds the bottom bracket bearings, cranks, derailleur etc. That would include welding steel or aluminium tube. If you can do that you can also design a fabricate a custom fork.


Shimano 105 11 speed rear derailleur won't shift

This is an interesting one - if we treat it as a derailleur that won't move right, perhaps work backward to the cause, instead of working forward from "where could water go to cause this?"

Start by cutting the problem in half.  Suspend the bike from a work stand or hang it up with some rope.   Pedal with one hand while hauling on the wire that runs down the downtube.  You should see one derailleur move.  If its the wrong one moving, pull the other cable.  As you add tension, the rear derailleur moves closer to the wheel/an easier gear.  The front derailleur goes the other way - gets to a harder gear as you add tension.

The point of that is to see if the issue is in your shifter lever up the top, or the derailleur.

Next is to gently push the derailleur with a finger while pedalling slowly.  Do watch out for finger-eating gear bits - possible damage can range from "ouch" to "I can only count to nine and my bike is painted blood red"  You are duplicating the action but taking the cables completely out of the picture.

Why?  Cables can rust up and mess with shifting.    Going around them can show that.

Finally, take some decent pictures of the rear cassette area and post them in your initial question.  Then we can go a bit further.


How can I find a biking club that has a group for riding with kids in a trailer?

Besides talking to individuals in your local bike shops, you can look for 'recreational' or 'touring' clubs. A Google Search for Bicycle Touring Clubs turns up clubs like our club in Utah, Bonneville Cycling Club (formerly the Bonneville Bicycle Touring Club).

Larger recreational or touring clubs will usually rate their group rides by a couple of measures like distance and average speed, and will sometimes classify rides as drop/no drop (meaning that in a 'no drop', the group slows to the speed of the slowest rider).

Pick the slower and shorter rides to begin with, and be prepared to be fully self-supported.  I would welcome riders with a trailer or trail-a-bike on most of my recreational rides, but it can be frustrating if those riders really can't hang with the regulars.

Finally - try to preview the group's route if possible.  Most recreational group rides stick to quieter roads with wide shoulders, but you need to be aware that with the trailer you will be much harder to pass.


There is a type of whitish liquid sealant that some folks (shops, manufacturers) put inside tubes, so that if you have a small puncture it is autimatically sealed by the liquid, which solidifies around the tiny puncture.

From what you say, it is not possible to say if that is the case, or if the puncture is larger and water went inside the tube. That would theoretically allow for the powder inside the tube to form a gooish liquid, although I doubt there would be enough amount of water for it to be noticeable.

From my experience, patch glue doesn't mix well with these white sealants, in every tube I patched that already had this liquid the patch got loose soon after, resulting in another flat. So I gave up these sealants forever, unless something new and different appears.

I would suggest, in this case of doubt, that you use the tube's rubber for another stuff (tying something at home ;oP ) and buy a new tube. That is not so expensive, and buyng new tubes is integral part of cycling, anyway. Besides, you could cut the old tube to look inside it and get more info which could save you future trouble (Where did this tube come from? Would other new tubes contain the same liquid? Was it sealant or just water? Etc.)

Saving old ones for "reuse" too, they are much more useful in the basement than in the landfill.


Upon further research it seems that in 1966, Schwinn was using Huret dropouts, which have a different configuration than modern derailleur hangers, which are based on a Campagnolo design. So the options are to get a Huret derailleur, or make an adapter like this one made from a washer or look at this thread for some other options.


Here are my snippets of advice from when I learnt to trackstand:

Start off by practising on a slight uphill. This way you only need to practice the forward pressure part of the movement. As you get better you can move on to smaller and smaller slopes. In urban riding, you can often use the camber of the road as your slope.
Use the right gear. Not really an issue with a fixie, but on a bike with gears you want a gear that is in about the middle of the range. Too low a gear will give you too much leverage and you will tend to over correct. Too high a gear and you won't have enough leverage to move the bike easily.
I find it easier to track stand standing up, pedals horizontal with my good foot forward and with the saddle braced between my thighs. Later you can progress to seated trackstands.
If the bike starts to lean towards the direction that you've turned your front wheel, then a slight pressure on your leading foot should shift the bike back under you.
If the bike starts to lean in the opposite direction, then you have to ease off the pressure on your front foot and let the bike roll back down the hill slightly. This is probably the trickiest part to get the hang of as it is a fairly unnatural backwards motion at first, but once you get the hang of it your trackstands will progress well.


Can I use rimless tape with an inner tube on a regular (tube style) rim?

The short answer is yes. Tubeless tape will support using a tube just fine. Tubeless tape does not stretch (much) so the indentation at the spoke holes is very minor.  Remember it is holding back the same force per square inch as regular rim tape, if it gave way the edge of the spoke holes would cut the tape and the tubeless tape wouldn’t be doing its primary job of retaining air. Finally, while the adhesive does a great job of keeping tubeless tape in place, it can still shift  if extreme lateral force is put on the tape (e.g., a very tight tire + tube+ rim combo)


It's set by the crank, and is like this because GRX is targeted at 135mm/142mm rear ends. GRX takes the same BB as any HT2 road crank.

It's enough to matter, but chainstay length is the other piece of how much it matters. Doing this kind of thing on super short chainstay bikes can yield pretty compromised results in terms of number of rough combinations, and at the other extreme may not be such a big deal.


You're right - a cold battery cannot provide as much power as a room-temperature battery.

I had an ebike based on SLA batteries, and in summer it would get 25 km range, which dropped to under 5 km in the cold frosty mornings of a winter.

It is possible to get battery heaters, common in places like Canada where its cold enough to freeze the water in a SLA battery and split the casing.  But on a bike you're going to be using battery power to keep the battery warm.  A better solution is to store the bike inside at both ends of your journey.

Perhaps a wrap made from a thermal blanket could help keep heat in, but there are downsides to that too.

Suggest you read To what extent should I insulate an electric bike battery during winter?


How does my tire pressure effect the tire's maximum load?

I weigh just over 120KG, and the wheels say that at 50 PSI, the max
  load is 90KG... Does that mean that I should then increase the
  pressure, to increase the maximum load, or decrease it?

The max load on a tire is restricted because higher load can cause a pinch-flat at a given pressure - and the max pressure is limited by the tire properties (and also by the rim strength).

So if you run your tires at maximum recommended pressure 50 PSI, you risk pinching the tube. If you inflate the tire more than 50 PSI, risk of pinch-flat goes down, but the manufacturer does not guarantee that the tire will not explode.

Ideally, you should have selected tires which are specified to bear your weight. In practice, this may be less of an issue because of at least the following:

the vendor might have indicated the "load" as load on just one wheel. Then, as said in the comment, your most loaded wheel is carrying just about 90kg.
1.95" MTB tires are designed for MTB, so there is probably less chance of pinch-flat while riding onroad.

So answering your question: the pressure should be increased, but the tire specification limits the maximum safe increase.


I will focus on the chain tension part of the answer, as your big chainring is clearly worn out. However, do note that increasing the derailleur spring tension wouldn’t stop the chain skipping on the worn chainring. Therefore, this answer is mainly for the sake of interest.
By chain tension, I believe you actually mean the tension in the rear derailleur spring. This spring takes up slack in the chain. If your spring tension were too low, the chain could be slack in some or many gears. However, I don’t believe that it’s a setting most users need to manually change, as the factory tension is likely sufficient. From this Park Tools page on overhauling rear derailleurs, Shimano and Campagnolo RDs appear to have one setting for increasing the cage tension from the stock setting. SRAM appear to have one setting higher and one lower. I actually don’t know of any clear reasons you would want to increase the cage tension, but it is possible to do so. I suppose that if you were converting to 1x without a clutch equipped RD, you might consider increasing the cage tension, as discussed in this previous Q&A. (If you do this, you might consider using a chain guide as well.)
Less relevant to you, I recall that Friction Facts, an independent researcher later bought by Ceramicspeed, showed that all else equal, higher cage tension meant slightly more drivetrain friction, although manufacturers objected that the cage tension was necessary to ensure good shifting. I believe that Ceramicspeed’s oversized pulley cages contain at least one position which lowers the cage tension from the stock Shimano or Campagnolo setting. The amount of drivetrain friction at stake is quite small, likely considerably less than 1W.


What needs to be changed if I put in a larger chainring?

You need to first check that your front derailleur has enough capacity to handle the new chain rings and can clear it (i.e. you can re-position and adjust the front derailleur to handle these chainrings). You should refer to your front derailleur's data sheet to see if this is possible. In general, you also need to check the rear derailleur's capacity to see if the rear derailleur is long enough to take up the extra possible slack, but in this case, the capacity required will go down for a fixed rear cassette, so you don't need to worry about it. You also need to make sure the chain adequately clears the frame under the new chainring size (which may require changing the bottom bracket or other things, if possible).

Here are some directions on adjusting the front derailleur.


top tube angle on steel and carbon road bikes

The only real advantage to a compact geometry road bike is for the manufacturers. Since standover- which is the distance from the top tube to your crotch when you straddle the bike with your feet on the ground- is increased, one size of frame will fit a wider height range of people and therefore the manufacturer does not have to make as many different frame sizes. This is valuable for aluminum and steel bike frames, but pays off the most in the world of monocoque carbon frames as each size requires its own mold(s) and for higher end bikes, its own layup schedule. Final fitting is done with saddle height & fore/aft position along with steerer stack height, stem length & angle. Ultimately there is no difference in fit between compact and classic road bike geometry.

Compact geometry frames use ever so slightly less material in the frame, but primarily they are just the new aesthetic of road bikes as compared to those of the 1980s era and before, and that era of bike was typically steel.


I don't think there will be a clear roof vs. trunk recommendation as both systems have their pros and cons:

Roof

Pro

Does not cover the trunk lid (access to the trunk when fully loaded)
Bikes stay cleaner (Especially when raining - on the trunk, the rear of the car sucks up road grim which gets into the bikes moving parts)

Con

You have to lift the bikes up to the roof for mounting (more or less difficult depending on your size and roof height)
Significantly changes the car's steering and wind behaviour
Higher wind resistance, therefore higher fuel consumption
Risk of driving under a low object and significantly damaging bike and car (Putting a small sticker on the top of the windscreen in front of the driver - I use a red arrow - meaning "Bikes on roof")

Trunk

Pro

Lower wind resistance, therefore less influence on steering and fuel consumption (With modern cars such as the Mazda 3, this is surprisingly significant)
Loading/unloading is easier
Can see if bikes become insecure

Con

Maybe prevents access to the trunk when fully loaded (may depend on car and rack model)
Influences sight through rear mirror
Blocks rear lights and number plate (Legal considerations in most countries)
Bikes more prone to damage - Major : accident, dragging on ground, Cosmetic: rack design.

For the scratches: the roof mounted one has the advantage of using points on the car that are dedicated to mounting, which means that there's very low danger of scratching your car (as long as you are careful when mounting the rack itself). The trunk mounted racks normally have some foam rubber on their fastening parts, which normally also prevent the car from scratches. So here, there's also normally no problem.

As long as you don't buy the next best cheap rack but have a look at some tests and invest a bit more money, both types will do their job. Also, as long as they have a reasonable mounting design (that is understood and used correctly), highway speeds (130km/h, 80mph) shouldn't be a problem with any of them. On the other hand, both types can be dangerous if the bikes are not properly fastened on the rack. As far as I know, the German technical control board (TÜV) and automobile clubs recommend the trunk version over the roof mounted one where possible, because of their lower influence on the steering of the car.


Which inner tube do I need to buy for 28 inch fixie bike?

All you need to know the wheel rim diameter, tire width, valve type and valve length.

Google translate to English of what's written on you tire is:

  Tire front Brand: Kenda Type: K-193 Size: 28 inches Tire width: 28 mm

28 inches refers to the wheel diameter. This means a rim with a rim tire bead seat diameter of 622mm, also known as 700c (and 29 inches for mountain bikes).

Tire width: 28 mm means, well, the tire is 28mm wide. Typically tubes have a minimum and maximum tire width they will support.

See here and here for determining what valve type you have.

You need valves long enough to reach through the rim with at least a couple of centimeters protruding.


A google reverse image search tells me it's a Martone Sweetzer (US) or Real (European version).

http://www.martonecycling.eu/product-EU-5-25-Womens_Real

From certain features of the frame (the bend in the top tube etc.) I'd say that's the same bike, but that your picture is of a slightly customised version with a different saddle and grips.


Comparing gear ratios on different bike types

Typically you quote gear sizes in gear inches, very basically this is the drive wheel diameter multiplied by the ratio between the two gear cogs, traditionally quoted in inches.

Also sometimes mentioned is development which is the amount of distance travelled by one revolution of the cranks (the astute will notice that is going to be proportional to gear inches and possibly a more meaningful quantity).

The more complex alternative, but one which is an absolute number, rather than measured in distance is Sheldon Brown's gain ratio  which tries to include the crank length in the equation to get some sort of appreciation for the extra work for the smaller cranks found on, e.g., road bikes in comparison to ATBs. So for every unit travelled by the pedal on its circular journey, the bike will travel x units along the ground.

Hubs will still have an absolute number of sprockets, even if it is just an equivalence to a real cog so can still contribute to these equations.


Should I buy a Dahon or wait for a Tern folding bike?

I think that the only possible answer for this is to wait and see. If I needed to buy a folder now, I'd stay away from Tern until they became a more established company. While it's possible they may take over the market and distribution channels, it's also possible that this new company may fold (no pun intended).

Dahon seems a good bet for the near-term. Just supposing that Dahon stops distributing all spares tomorrow. If nothing else, there are many Dahon spares already in the wild, and will be available for puchase on eBay if nowhere else. Tern is a new company and doesn't even have that. (This is, of course, discounting the possibility of Tern and Dahon using any of the same parts.)

If you want a Dahon, I'd go ahead and buy one. The company's not going anywhere just now. If the Tern bikes look sweet, when they become available you can pick one up. Just remind yourself that they're a new company and spares may or may not be available. And lastly, if you want to stay away from the whole mess, you have other options for folding bike brands, as has been pointed out. However, you're pointed out that your preference is to stay "in the family". In that case, is upgrading your current folder an option?

(This question can't really be answered satisfactorily either way, and I hope that in time someone else will write better answer as more information becomes available on the Tern/Dahon rivalry.)


Broke the lid cover of my Shimano Deore combi hydraulic brake reservoir. Repair options?

If you have only broken the upper part, which I have marked A on the exploded view diagram, then I don't think that serves a functional purpose other than making the brake levers look nicer. Therefore, you should be able to continue to use the levers so long as part B is in place, but without the added thickness of part A, the screws (part C) may be too long to fit in the threaded holes in the lever body. Shimano lists these as being 'M3 x 8', and they appear to be Phillips pan-head machine screws. You'd want to buy some M3 x 6mm machine screws to replace them and be sure of not bottoming out the screws.

Alternatively, Shimano make available the entire reservoir cover assembly, (26) on the diagram, under the part numbers Y-6JK 98080 for the right-hand assembly and Y-6JK 98090 for the left hand assembly. You may be able to find an online stockist of these spares, or possibly ask your LBS to order them from Shimano. However, as M760 series Deore XT is relatively old, it is unlikely that any spares will be available direct, and you'll have to hope that shops have the parts already in stock.

The full exploded view diagram is available at https://www.paul-lange.de/support/shimano/explosionszeichnungen_archiv/ST//ST-M765.PDF


The 'part of the hub the cassette mounts to' is the freehub body. That is evidently loose, or damaged.

5-8mm is a lot of movement. Don't ride the bike until you have fixed the problem. You would likely damage the freehub mechanism, and may suffer a jammed chain which could be dangerous.

Each manufacturers freehub disassembles in a different way. This Park Tool article will give you and idea of the types. First step is to get your cassette off and find out what type of hub you have, then find specific instructions for disassembling and inspecting it.


What are the consequences of a chain that is the wrong length?

If the chain is too long then in some gear combinations (e.g. small/small) there will not be enough capacity in the dérailleur to pick up all the slack, so the chain will be loose.  At an extreme case, the chain could sag and come into contact with the chainstay.

If the chain is too short then in some gear combinations (e.g. big/big) there will not be enough chain to span both gears and go through the dérailleur.  In this case it might not be possible to change to this gear, or doing so could damage the rear mech/mech hanger.

In a bike with rear suspension, there also needs to be sufficient extra chain to compensate for chain growth when the suspension compresses.  Running too short a chain could mean shifting to big/big is possible, but compressing the suspension when in this gear damages the rear mech/mech hanger.

Typically there will be a range of chain lengths in which the gears will function correctly and if the chain is only a little too short/long problems would only become apparent in poor combinations such as big/big and small/small


Can I use Shimano's Di2 e-tube project software to do a custom lock out of additional small sprockets while in the small chainring?

My mountain bike doesn't have Di2, so this answer is based on my road bike Di2 experience..

  1) Whether there are options like 44/33/22 in the crankset dropdown, and

The e-Tube project software will only list crankset options that are actually available in Di2 series hardware. What I mean by that is if you're using a road bike Di2 Front derailleur (Ultegra or Dura-Ace) but a 105-series cassette/chain ring, you won't be able to select that.

  2) If there's aren't super close options, can I manually enter my chainrings?

Nope! Sorry :(

  3) If necessary, can I ask the software to lock out EXTRA small sprockets on the cassette when in the smallest chainring?

Nope! But you could set up synchro-shift to determine when it automatically shifts to the next gear (and thus prevents cross-chaining for you). Note that the rider could always switch off synchro-shift (change to different shift mode) OR change from big to small chain ring when in the smallest sprocket and cause cross chaining that way.

More info on synchro-shift: https://di2center.com/2019/02/16/synchro-shift-how-does-it-work/ and https://di2center.com/2019/04/05/how-to-customise-synchronized-shift-settings/


Difference between Shimano SM-RT81 and SM-RT81-A rotors?

You need to determine the model number of the SLX brake caliper as the BR-675 caliper requires a wide-type rotor and pad as well.  New BR-7000, 7100 & 7120 SLX calipers use narrow type rotors and pads.  The SM-RT81 rotor is a narrow type and only compatible with the latter SLX model numbers. Shimano's Compatibity Chart for disc brakes/rotors.  Also note the section "Interference Between Disc Brake Caliper & Rotor.". Significantly it advises one to avoid using an M675 caliper with RT81 rotor.
Whether this is the reason your pads are sticking out is still in question.

Determining the model numbers of your caliper and pads and comparing to the compatibility chart linked above would be a good place to start.   The "A" at the end of a model number represents "standard" version of the small part (which is what the "SM" represents). Based on my interpretation of Shimano's published info, the variation in the model number SM-RT81 is related to differing diameters available.  These different sizes are denoted SS, S, M, L as a suffix at the end of the rotor model number.

Some other considerations mechanically are that the rotor pistons have been pushed back in after the old pads removed and prior to the new going in. Check the new pads return spring is oriented correctly and that the eyeholes of pads and spring line up.


You likely want a floor (track) pump - something that looks like this:

(Image from here)

Most good floor (track) pumps have support for both Presta and Schrader valves, usually through two opposite ends of the chuck:

(Image from here)

If your pump only supports Schrader valves but you have a Presta valve, you can go to your bike shop and buy an adapter for Presta->Schrader for around a dollar, each. (The reverse case is rare to occur, but adapters do exist but they're around 8 dollars a piece)

To pump up a Presta valve, you unscrew the nut, tap the nut to let a bit of air out (so that the valve isn't stuck), push the chuck onto the valve and lock it, then pump, tighten the nut. Dust cap is optional. Schrader is identical to the procedure on a car.

As for which pump to buy, make sure its rated to an appropriate maximum pressure, has a good warranty and has good reviews. Going with a good brand helps too, but you don't need to spend much. I've been using a Topeak Joe Blow Sport II which I got for around 30 bucks with no problems for the past 2 years.

Frame pumps are a different matter, but they're primarily for people going on longer rides who won't have access to a floor pump in an emergency. Shock pumps are for people who have air suspension to fill their forks, and are also a different matter.

A non-exhaustive list of quality manufacturers include:

Topeak
Park Tool
Lezyne


How can I replace my front cog... or fix slipping off on folding bike?

If a new chairing is the solution, then the best chainring to solve your issue is a 1× specific narrow-wide chainring. I'm not able to identify your crankset/chainring interface from the Amazon link. Once you know this, you can see if there's such a chainring available or if you'd need to replace your crankset entirely (probably too expensive to be worth doing on this bike).

I would also be tempted to check if you can shorten your chain by one link. This would mean that your rear derailleur would hold the chain on the chainring more tightly.


How to calculate rigid fork replacement for suspension one?

If you want a rigid fork for a 29er with shocks just buy a fork for a suspension corrected frame.  If the fork is listed for a mountain bike then it is (probably) suspension corrected.  I suspect that about any rigid fork that will take a 2" tire will be suspension corrected.

Measuring is not going to do you much good as you can't buy custom lengths (that I am aware of).

Below is a suspension corrected rigid - see the space at the top:

For a workout bike I don't get why you need 2" tires?  You are going to have trouble finding road 2" tires.  There are some rigid mountain bikes (Niner Ross 9 Plus) and also the Salsa Fargo.  Another option would be to buy a used mountain bike priced right because of a worn out shock.


There's no frame material in the world that will absorb bumps like a bike with a suspension fork/frame.

However, the original "suspension" invention that made bicycles practical was the pneumatic tire. If you have a rigid frame and fork, that's all the real suspension you have.

Skinny road tires at high psi have about 2-3mm of "travel", a fat commuter tire at 60 psi will have close to 25mm of travel. A suspension fork generally has about 100mm of travel.

A CX bike is a good choice to build a commuter around since they generally take fatter tires ( usually up to 32mm ), but there's absolutely no reason to get a carbon CX bike for commuting. Especially one that does not take a rack or have fender mounts.

With fat tires at the correct PSI, I think you would have a very hard time distinguishing between different frame materials in a blind test. Geometry and tire size make so much more of a difference than what the frame is made of.

To enjoy your commute, I'd recommend finding a balance in the middle. A bike with suspension is going to be heavy and slow and overkill 99% of the time. A "racy" carbon CX bike is going to be fast, but rough and the handling will be a bit twitchy. A good commuter should take fat tires(32mm at least), have a relatively long wheelbase and slacker angles.

But you can commute on anything. You might just try putting slicks on the bike you already have and see how that works for you. If you are going to get a new bike, I'd really suggest looking at CX/commuter bikes with disk brakes.


inner tube to fit in a 26 X 1.5 bicycle tire

A tube can usually fit a range of different tire sizes, because the tube can stretch a bit when it is being inflated.  The range of tire sizes is written on the package that you see at the store. Since your tire is 26"x1.5", you need to find a tube that is labelled as being appropriate for a 26" (diameter) tire and a width range that includes 1.5".

For example, look at this picture:

Among other things, the label says 26x1.5/2.20. This means that it's intended for 26" tires where the width is between 1.5" and 2.2". So this one would work for you. I hope this helps in deciphering the labels if you go to a bike store.

A previous answer mentioned the two different kinds of valves; this is important. You just have to look at the valve on the old tube that you want to replace and figure out if it's Schrader or Presta.

Presta valves look like this:

And Schrader valves look like this:

If you want to buy it online, here are two that would work:

With a Schrader valve: http://www.amazon.com/Avenir-Regular-Schrader-Valve-1-50-1-75/dp/B00165PA1W
With a Presta valve: http://www.amazon.com/Diamondback-26x1-5-Threaded-Presta-Bicycle/dp/B00MJYP0KU


Over-locknut dimension (hub distance) (cup depth) changed after 10.000km

So it is not a diameter, it is distance! 135 mm is a classic value for rear MTB wheels with 8-11 speed cassettes. 128 mm sounds more like a hub with freewheel would have however.

O.L.D. is a parameter for the axle (over the locknuts distance), not the hub shell width you show on the pictures. Having more washers or thicker cone washers on the old hub might explain the difference you see.


What tool is needed to remove KMC X11 w/MissingLink, 11-speed chain?

Any tool that can be used on an 11-speed chain should work to 'break-the-link', i.e. push the pin (rivet) out.  I have never updated my Park CT-3 tool in years and have used it on a variety of chain variations, from 8 speed up to 11.

You should look for a KMC replacement master link, as most manufacturers do not recommend using other manufacturer's master links.

I'm not a huge fan of pushing pins back in place, but if you have the right tool, it is doable, the simplicity of the self-locking master links makes reconnecting the chain way easier--I carry both 10- and 11- speed links with my, never know when you might need one, or can help someone out, they are light and cheap enough.

I personally have the KMC Connector and Removal tools, I really like the connector tool, as the 'stomp-on-the-pedal' method seems sketchy, imo.


Put the spacers back in and see how it feels. If it feels better and your gears a shifting well enough for you, leave them in.

As @Daniel says, chainline is not as important as some believe. In a perfect world, you get the chain line right and never, never, ever, cross the chain. But just like the movie, sometimes you just have to cross the chain, and hell does not freeze over.

New MTB's are going to 1x11 (and 1x12), and the cassettes are wider than 9' or 10's. If chain line was so critical, these 1x11 would never work.

If your chainline is badly out, you may have problems getting shifting to work as smoothly as it should, your chain may wear a little quicker than it would, and the little cogs on the derailleur may wear out a little sooner. Notice the word may, and its a a very small if it does, and very debatable.....


Can I use a road bike for commuting 11 miles each way without SPANDEX

Yes, absolutely.

Clothing is mostly an issue of personal preference.  Performance fabrics and things like spandex don't make that much difference for short stretches, and their advantages become more pronounced and valuable the longer you ride.

11 miles is somewhat of an intermediate distance; in regular clothes you'd be totally fine, assuming that the weather and the road conditions won't make your work clothes sweaty or dirty by the time you get there.   For commuting to work, I'd make the decision more on the basis of road conditions and comfort.


In clincher tyres, are folding tyres easier to put on and remove than the tyres with wire bead?

Both the easiest and the hardest tyres I've mounted have been wired, but all the folding tyres I've had have been at least moderately hard.  When fitting you don't want the bead to fold, you want it to be almost a perfect circle (just very slightly distorted as you pop it over the rim).
Wired tyres tend to get a bit easier to remount after they've been used for a while, but folding tyres don't seem to.  The wire is wound, and I suspect there's a tiny bit of stretch available.  Also if the wire isn't perfectly round to start with, fitting it for a while will pull it into shape.
It is possible for tyres to go on too easily, then they pop off again.  I've had that with a wired winter tyre that was easy to fit the first season, and wouldn't stay on when I refitted it the next year.


Installing a lock mount on a carbon fiber frame

I've mounted lights with similar clamps on carbon forks with no ill effect (just have to be very careful not to over-tighten the clamp) but a lock -- which is heavy -- might put a too much torque on such a small clamp.  Maybe if you could spread out the area over which the clamp attaches to the frame then it might be ok.

What about attaching the U-lock behind the seat?  Hang two loops (tie wraps, wire, string, etc.) from the seat rails and pass the straight portion of the lock through them.  Then secure the bottom of the "U" to the back of the seat post with a velcro strap (put some padding between the lock and the frame so that the lock doesn't bounce and scrape the seat post up).


Can I install a back bike rack without attachment to the rear part of the frame?

Several manufacturers make replacement seatpost collars with integrated rack mount holes. Just make sure you get the right diameter for your seat tube. Here is an example:


Best bicycle for a moderate to extremely hilly suburbs?

If you're after just a rough outline, I've listed the below:

Type of bike: Do you think you'll ride on-road or off-road too, i.e. would you need a road bike or a mountain bike? It is possible to get a hybrid bike, which is essentially just a mountain bike without shocks and road-appropriate tyres
Gears: Most modern bikes these days will have gearing of up to 11sp on the cassette in the rear. You'll also often have the choice of up to 3 chain-rings ion the front. Smallest ring in the front and largest gear in the back makes for easier hill-climbing.
Brakes: If it is very hilly and you'll want to have good stopping ability, disc brakes would definitely be a good call.

Most importantly, when you sit on or ride the bike, it should feel right and it must be comfortable.  Most bike shops will let you do a test ride.  Go around the block a couple of times and make sure you are comfortable and can work the gearings easily.

Don't spend more than you want to. It is really easy to spend many thousands and thousands of $'s on a bike.  Set a budget and stick to it as far as possible.


How to decelerate during long downhill rides and avoid brake glazing

Brakes work by turning kinetic energy into heat through friction. As you heat up the system there generally is less capacity to absorb more heat (in addition to physical changes  in the brake system component).

Constantly dragging your brakes is probably the worst strategy. Tandem bikes do this but they typically have one braking system dedicated to being a drag brake, and a separate braking system to be used for stopping. If the drag brake fails from overheating the primary brake system should be unaffected.

The reason constant drag braking is a bad strategy if you do not have a dedicated drag brake is as follows:

The brakes never get a chance to cool off, building up heat over time which can make them ineffective if for example you need to suddenly stop;
If you are drag braking to maintain a slow speed then you are not taking advantage for aerodynamic drag. Drag goes up with the cube of velocity. As such you get the highest braking force from aerodynamic drag the faster you go (yes it does sound crazy).
If you are not effectively using aerodynamic drag you are forcing your brakes to do proportional more work (i.e., heat) than if you let your speed run up then brake.

Depending on your tolerance for speed (I am personally happy running my speed up to 90+ km/hr), the optimal strategy is to let your speed run up, do a period of braking where you drop your speed down (e.g., go from 80 km/hr down to 40 km/hr), let off the brakes and let your speed run up. This lets you cool off your brakes as well as use aerodynamic drag to your advantage. The key is to try and have long periods between a braking bought so you can get as much heat out of your brakes. If the period between a braking bought is too short (e.g., pulsing your brakes) you will start to get excessive heat build up in your brakes eventually leading to fade and even failure in some extreme circumstances.


Face gets extremely red when biking in the cold ~5c, and then going indoors, due to temperature change maybe

You can't really wear anything to solve the problem you are describing.  If your face was cold, I'd recommend you purchase some sort of mask, however, that isn't your stated problem.

When you exercise you generate heat, your body tries to channel that away by dilating blood vessels and sending that heat to the surface (your cheeks) where it can radiate away.  If you are cycling when it is cold, it can reinforce that effect since your body would be sending extra blood to try to heat your cold cheeks.  If you have generated a lot of heat cycling, then go indoors, you may also feel extra warm now that you have a lot of generated heat, are dressed for cold weather and in a warm room.  Again, flushed cheeks.

I regularly bike to work in cold temperatures.  I start wearing a mask at 0F to protect both my lungs and face.  It's a very normal occurrence for me to have red cheeks up to an hour or so after arriving at work.  People sometimes comment, but I know it's normal for me.  I only start to worry if I get white patches (frost nip or no blood flow to areas that were over exposed).


Goofy bike lane configuration right-of-way

I would say she is at fault. Here is why:

Since she was driving a car and you were dragged for some distance after the collision it appears she was traveling at a higher speed and thus was from behind. The responsibility typically falls on the one from behind. Even if the contact wasn't on your rear it sounds a lot like rear-ender.
A bike lane is a lane of traffic and has the same rights as other forms of traffic. Yes, @Willeke is correct this is poor street design, but this is not your fault. You were traveling straight and the car was the one initiating a turn and it was her responsibility to pay attention necessary to complete that turn safely. Yes, perhaps you should of paid some attention too, I hate it, but I watch out constantly for cars doing bad things. Convincing others that those who done did the bad things are at fault will be the hard part, as there is a contention that bicycles are toys not destined for the roads. But, this is not what the law says. Please fight for your (and our) rights.
Harm done. Sadly the United States does seem to have law or the general mentality to structure things this way, but I think those wielding a deadly force (like a car) have a responsibility to those more vulnerable like pedestrians and those on bikes. You may be able to use this very valid point to garner some compassion, but your mileage may vary.

Good luck.


Just keep unscrewing (it's a standard thread) until it comes completely loose.  Typically the bolt for that style of kickstand is incredibly long, so you have to unscrew for a long time.


If you have a fixed gear type hub, not a dual freewheel flip flop hub, and a lockring which is properly installed, there is no benefit to using threadlock on a fixie hub.

Thread lock works just fine on aluminum, although it tends to cause stripped fasteners because it requires more torque than most aluminum fasteners can handle. With a fixie lockring, though, there aren't enough threads (surface area) to really benefit from a threadlocker.


Bushings vs bearings - maintenance difficulty

Bushings and bearings are nearly identical in terms of the replacement procedure. Personally I think bearings are the better option because bushings typically are manufactured and supported only by the bike manufacturer. This means when the bike becomes discontinued, most of the time, so do the bushings.

If you need a bearing replaced, you can typically look on the dust seal and get an equivalent Wheels Manufacturing Bearing.

As far as a specialty tool (for bearings), in a pinch, you can

Use a flat head screwdriver and tap the bearing out side by side
Press the bearing in with the correct sized socket from a socket kit

The press you would need can either be borrowed from an Auto Parts store, or use a long bolt, and a nut with a washer to make a "homemade" press.

See this video

The actual tool looks like this

For bushing replacement, unfortunately you do need a specific tool to get those guys out.


Will degreaser formula 88 harm your tire?

According to the FORMULA 88 Material Safety Data Sheet, this product is not dangerous, and is soluble in water. Washing it off was the best you could do.

My guess is that the solvent has dissolved some of the components of the tire rubber, leading to the fading and cracking you see. Only time will tell if the tire has been structurally compromised.

The most basic precaution would be to buy a new tire before this one fails.

You could continue to ride this one, if there are no signs of bulging from the internal pressure in the tube. But the conservative advice would be to replace it now.

Personally, I would put it on the back wheel and continue to ride on it, but keep it under observation. If the damaged area is smaller than a tube patch, I'd glue a patch on the inside. But if it starts to bulge, then I'd replace the tire promptly.


Will a 2x with a clutch RD be just as effective as a 1x with a clutch and narrow-wide chainring on an mtb?

It will help 2x, though 1x is going to hold chain better. I think you'll still see an improvement with a 2x setup due to added chain tension. When I upgraded the drivetrain on my full suspension to use a 10spd Shimano Deore clutch derailleur it didn't drop chain nearly as much if ever. Make sure you have your chain shortened to the appropriate length as that's one of the biggest factors causing chain slap and jumps is having a chain that's too long.

A 1x would likely work better if you switched to a narrow/wide chainring that prevents jumps though. I almost never drop a chain on the 1x setup with a race face narrow wide ring. The front chainring does a lot to stop the chain from slipping off due to the tooth profiles that really keep the chain engaged. I'm running a cheaper 10 speed setup on my hardtail with a sunrace 11-42 casette with a 10spd sram x-9 clutch derailleur and it works very well and was a cheap upgrade vs a whole new 11spd.


Centerlock largely exists because since the beginning of modern disc brakes for bikes, Shimano has more or less alone had a weird cautionary take on the physics of rotor bolts theoretically being able to loosen in the six-bolt design. That's why their six-bolt rotors have always come with various retention systems for the bolts that nobody else bothers with.

Centerlock doesn't accomplish anything special and doesn't allow for lighter hubs or rotors (at least in a meaningful sense). Shimano rotors are excellent so it's not like you're trapped if you have centerlock hubs, but you do have fewer options, and centerlock rotors are inherently more expensive at the low end because they can't just be flat pieces of steel.
Centerlock has the disadvantage that carrying a lockring tool plus something to turn it isn't practical, so the best you can do if you severely bend a rotor on a ride is undo the caliper mounting bolts and try to hang the caliper out of the way, which is awkward. Even though the risk here is small and theoretical, it's enough of a potential day ruiner that given centerlock has little to no functional advantage, there's an argument to avoid it if all else is equal. The catch is that all else is often not equal, because Shimano hubs are some of the best value choices.
Six-bolt does have the disadvantage that bolts getting seized, heads getting stripped, and/or hub threads getting damaged are all things that happen sometimes, whereas centerlock tends to be free from any such problems. Having one big high-torque fastener does create a more reliable interface in that sense. But it's a pretty fringe concern; six-bolt is perfectly robust and very few people will ever have to deal with a seized rotor bolt. However, in all fairness it can be a difficult enough problem to deal with when it does happen that centerlock usually looks pretty good by the second hour in.


Anecdotal accounts say "yes, you can mix within reason".

The manufacturers, however, will generally say a firm "no". On the one hand, they would, wouldn't they? They're in the business of selling kit. With road groupsets, there is Shimano, the main player. Then there is SRAM, who make their components to be largely compatible with Shimano. Lastly, among the main manufacturers, there is Campagnolo, who are compatible with...Campagnolo. For mountain bikes, things are a little different. Shimano still dominate, more arguably,, but SRAM's policy has generally been to buy existing, established brands. At this point I'm guessing somewhat, but I think incompatibility is the general state. Campagnolo aren't even players in the mountain bike marketplace.

With all systems, the width of the outside of thechain really drives everything else. Hopefully you can imagine, as you start putting more and more gears on the back, each cog must sit closer to its neighbour, and so the thinner the chain must become. This follows through to other components also. One of the most critical things is the rear derailleur, which is designed to shift the chain a certain distance every time you change gear. You can imagine that only the derailleur made for that number of gears will shift the chain the correct distance. If you mix this, the distance will not be quite right, although we're talking tenths of mm here between each gear.  So whilst the shifting is not perfect, you may judge it to be "good enough" by your standards. In that sense, it's a judgement call.

Lennard Zinn, who has authored a few excellent books on bike maintenance, has also written quite a bit on mixing over on Velonews.


Front brake cable loose from barrel adjuster

I'd guess that what happened is the other end of the cable slipped (at the anchor bolt on the brake). It probably wasn't tight enough and when the brakes were applied the cable pulled through the anchor bolt. Now the cable seems too loose at the barrel adjuster, but really it is too loose at the brake.

All you probably need to do is to loosen up the anchor bolt so that you can pull the cable back through and then tighten it down again. When you do this inspect the cable to make sure that it isn't starting to fray. If the brakes had been solid and this is a sudden change the cable fraying is one of the more likely reasons that I can think of for the cable suddenly becoming loose.


Do half link chains work on any bike and what is their purpose?

From the internet:

"Half Link BMX chains were designed to help dial in the chain length on frames with short dropouts and small gearing, making sure your rear wheel is exactly where you want it. Dan's Comp offers a wide variety of half-link BMX chains for both race and freestyle."

Basically, you can break your chain at smaller increments to get a more precise chain length. 1/2" instead of 1".

Half link chains should work with most single speed set-ups, but not with any bike with multiple sprockets / chain rings.


How to remove a crank arm with stripped threads?

Your crank arm is trashed.

With the crank bolt removed, gently ride around a few miles, it should work itself loose enough that you can yank it off.

Otherwise many shops have basically a slightly larger crank puller for addressing this issue, where they chase out a larger set of threads, then use the larger puller to get it off. The crank arm typically goes into the garbage at that point however.


Performance consistently better in the evening?

This is a very normal, but not particularly well understood phenomenon.

If you google "cycling higher power output in evening" you will find several published scientific papers showing improved performance in the evening.


Does a spinning class fixed wheel bike affect real world form?

The exercise bike feels different, because it is fixed in place and can not react to your movements like a real bike.

When you jump out of saddle, your body moves forward in relation to bike. On road, the you keep moving at roughly same speed and the bike slows down momentarily to accommodate the change in relative positions. A fixed exercise bike can't move, so you are moving and stopping instead and that is what you feel as jerking motion. Also, when standing on a real bike you rock the bike to keep your body in place, but since this exercise bike does not allow sideways motion you have to move your weight sideways to put force on pedals.


It looks like a glass cut to me.

It is common for glass to lurk in the tire case, so this is unusual.

Take the tire and tube off completely and inspect the inside of the rim and the tire carefully. If you can't see anything, run your fingers around the rim and the tire.

If you still haven't found anything, take the rim tape off and check it and the rim again.

If you still haven't found anything, reassemble, sigh deeply, and hope for the best.


Is taking a bike TRAILER on SF Bay Area Rapid Transit permitted?

I also contacted BART via the customer service email listed on the BART website and received this answer while out for the holidays:

  Dave,

  Bike trailers are permitted on BART, with the same basic restrictions as bicycles (no bikes in the first car, or on trains passing through downtown San Francisco, Oakland or Berkeley during rush hours).  The only additonal restriction would simply be extra awareness, as you will be using more space then a regular bike, and to avoid crowded trains, even if it is not during the restricted hours.  Thanks for choosing BART.

  Operator #6
  BART (Bay Area Rapid Transit)
  Transit Information Center
  Tel. 510-465-2278 (live operators)
  6AM to 11PM - 7/Days"

Hi,

I called BART and the person I spoke with was very nice and quite informative.

So, first thing is that you need to follow the standard BART bicycle rules. Basically, there are a number of bicycle restrictions regarding peak commuting hours. You're pretty much committed to following those rules.

According to the rep I spoke with, during "non-peak" hours, you may or may not be allowed to use a trailer. The station masters will look at the length of your set-up. So, during low demand periods, you're probably ok if your trailer and bike are detached and compact as possible.

So the message I got is this. You will not be able to commute during peak hours with a trailer. You're probably ok with some trailers during non-peak times; except at times when a big event is occurring in the city.

I'd suggest that you pick an off-peak time when it's not terribly inconvenient and try out your bike trailer set-up. Also, according to the BART rep, if you're organized about things and your trailer is basically a large piece of luggage, you're probably good to go during the off-peak hours.


How often should rear suspension frame linkages be serviced?

No, it's not typical maintenance, but you do have to take it apart to either replace or perhaps just service (degrease and relubricate) the bearings once in a while. Which you do may depend on what you found and how much disassembly of the bike's other systems it took to get there, which has become everything but the fork and front brake on some bikes, where the link and the internal hose/housing/wire routing are tightly intertwined. You do this more for bearing wear than creaks per se in most cases, although a creak may be the symptom that gets you looking.

Riding conditions have a major influence on the level of maintenance required. I live in the US Pacific Northwest, and we have a lot of fine clay soil and moisture that at times seems to create an almost perfect assault on suspension bearings, which would have a much easier life in other regions.

The more common thing to do for creaks is drop light oil or dry lube into the pivots, cleaning as well as possible first to avoid working in grit. Also make sure to keep all the hardware properly torqued. Torquing and lubing is the first thing to check when there's a creak from a linkage pivot.


How do I maintain my weight while cycling more?

I worked as a physician (not anymore nowadays, got into medical systems design), and I can guarantee you that either people and health professinals overemphasize the importance of the weight as if it was a single "magic number" regarding health, and it is not.

Body fat percentage, cardiovascular endurance, muscle and joint flexibility, dietary habits and psychological stress level are much more important.

Besides that, two things you must consider:

When one increases pedalling distances and speeds, fat is lost and muscle is gained. Muscle is much more dense, so even if you look lean, you do not lose so much weight, but you exchange a very risk-related tissue (fat) by a much more healty one (muscle). And even while at rest, muscle burns calories much more than the same amount of fat, so the very existence of more muscle implies a higher methabolic rate;
When you commute by bike, you get REALLY HUNGRY. You must eat, because food is your gasoline. Actually, wanting to lose weight by eating less then necessary is dangerous for bike commuters, because you might get weak during a ride, which greatly increases discomfort and accident risk.

What I do is to eat just enough, take a lot of salad and vegetables when possible (helps to provide anti-oxydants for the body, much useful for us who breathe pollution, etc.), and try NEVER to ride "out of fuel".

EDIT: (from wikipedia)
Some common body fat percentages (not a recommendation!)

            Women   Men
Minimal     10–13%  2–5%
Athletes    14–20%  6–13%
Fitness     21–24%  14–18%
Average     25–31%  18–24%
Obese       32%+    25%+

"The bioelectrical impedance analysis (BIA) method is a more affordable but less accurate way to estimate body fat percentage. The general principle behind BIA: two conductors are attached to a person's body and a small electric current is sent through the body. The resistance between the conductors will provide a measure of body fat, since the resistance to electricity varies between adipose, muscular and skeletal tissue."

I am not a native english speaker, so some words might not be correct.

Hope it helps!


Are road bike shifter hoods compatible across models?

In general, shifter hoods are not compatible between models. Campagnolo has had three different designs since the 90s and Shimano has had many more. If you know the exact model and year of your levers, you should be able to find both original and third party replacement parts online. Competent online stores should have a selection of hoods and list for compatible levers for each.


Use a chain wear gauge to see if the chain needs replacement (e.g. Park Tool CC-3.2).Generally, these err on the side of replacing a bit early, but if you want to be pedantic about it, you can use the Sheldon Brown link below to measure with a ruler.

As for the sprockets or chainrings, I'll defer to this page by Sheldon Brown. The upshot is that worn teeth look like ramps and a non-stretched wont sit properly in the sprockets as shown in the image below (from Sheldon Brown)


Creak in bottom bracket, resistance while pedalling backwards

Answer Your bottom bracket is stuffed.

The cheap AND the correct fix is to replace it outright.  All I found on the web was that this bike has an "external bearing system" bottom bracket, which could be any of 9 different standards.

The replacement has to match the crank interface too, which could be ISIS, Octalink, or square taper.

Specialised tools for this - you might need a crank extractor, which forces the two crank arms off the bottom bracket spindle.  Then you need a special wrench to undo the visible round bits poking out the side.  They may be threadded or they may be pressed in.

Lastly you may require a press to push the two halves together or you may get away with using the special wrench to thread them back in.

You'll also need grease or copperslip, and standard workshop tools.

Would be cheaper to get a LBS to do this if you don't own or want to own the tools.  And a BB should last you at least 10,000 km.


Handlebar of my bike will not bolt onto the front forks

Sounds like a quill stem, something like this:

That wedge bit at the bottom sounds like its come unscrewed completely.  Take the stem out, and look down the hole.  If you see a lot of light, then you've dropped the wedge and its gone.

If there's only a little light coming through the bolt hole in the wedge, then flip the bike, take the front wheel off, and any front mudguard, and poke the long bolt up from below.  The wedge should fall out the top.

Once you have a wedge again, loosely bolt it to the stem with the long bolt as pictured, insert into the steerer tube, and reassemble.


Canyon Ultimate R8000 front derailleur - can't get low enough

Amateur hour. Turns out my K-Edge chain catcher was actually blocking the derailler from moving into the lower position. It looks like this chain catcher is not compatible without modification for use with R8000.


Are Penny-Farthings Legal to Ride on Public Roads (UK)

UNITED KINGDOM
Intro
I ride a 50" Penny-Farthing almost daily on the UK's public roads, both individually and as part of groups in daylight and evening conditions.
Before venturing out onto the UK's roads when I began my Penny-Farthing journey, I asked myself this very question. And when people see me on my PF, many will invariably ask me: "Is that thing legal to ride on the roads?!?!?"
Initially had to piece together an understanding from a gazillion different sites. This answer hopes to centralize this research into a single comprehensive, authoritative PEER REVIEWED source for riding Penny-Farthings on public roads in the UK ONLY. And save the reader the grief of hunting-down this information across many sources.
Please alert me to errors or omissions you may spot in the comments section and I'll revise the answer accordingly.
SHORT ANSWER:
"Yes", but only if you observe all the traffic laws you're required to riding a regular "safety" bicycle (those odd things with symmetrical wheels) and your Penny-Farthing has the minimum safety equipment required by law (see "LONGER ANSWER" for specifics).
LONGER ANSWER:
Governing Laws on Cycling:
A Penny-Farthing is a bike, albeit a direct-drive bike without symmetrical wheels, but nonetheless still a bike and subject to the same laws as any other bicycle ridden on Public roads.
The (5) key Laws relating to bicycles - ALL bicycles - are:

The Highway Code: When interpreting the Highway Code, the words MUST and MUST NOT imply a legal requirement. Anything not so qualified is advice. HOWEVER: If you're ever involved in an accident and find yourself in court, your failure to observe best-practice as advised in the Highway code could go against you; only a downside in not heeding advice in the Highway code if you are cycling on public roads.

THE HIGHWAY CODE, Northern Ireland: Northern Irish Penny-Farthing Riders be guided by this.

The Pedal Cycles (Construction and Use) Regulations 1983

The Road Vehicles Lighting Regulations 1989

The Road Vehicles Lighting (Amendment) Regulations 2005

The Pedal Cycles (Construction and Use) (Amendment) Regulations 2015

Older Penny-Farthings manufactured before these laws were enacted can be outside of them. However, most Penny-Farthings manufactured in modern times WILL necessarily be subject to ALL these laws.
The guidance in this post is based on prevailing laws at the time of writing. Laws changes over time, and with the rise of "e-Bikes" I expect cycling laws will be revisited in the near future. Future readers are advised to give me a heads-up if anything becomes out of date and I will revise this answer accordingly.
Obedience to ALL Traffic Laws:
Braking/stopping on a Penny-Farthing brings challenges one doesn't encounter riding a "safety" bicycle where you can put your feet on the ground at a halt. Nonetheless you still must stop at red signals, yield to traffic on your right at roundabouts and signal changes of direction. If you cannot perform these fundamental operations competently on a Penny-Farthing, even if your PF is appointed with all the correct equipment which is described below, you shouldn't be riding it on the public roads.
Brakes:
Regulation 7 of The Pedal Cycles (Construction and Use) Regulations 1983 defines the legal requirements for brakes on a pedal cycle. As a Penny-Farthing is a "fixie"- a direct-drive bicycle where only one wheel is operated by the pedals. 7(1)(b)(i) of the statute requires only a SINGLE braking system.
UPDATE: I asked Roger @ unicycle.com- who is the manufacturer of the popular UDC Penny-Farthings of which I'm a rider of- to review my answer for correctness and he states that  Rule 9.1 trumps Rule 7(1)(b)(i) in respect to brakes on a "fixie".

9.(1) Nothing in Regulation 7 or 8 applies to -(a) any pedal cycle so constructed that the pedals act on any wheel or on the axle of any wheel without the interposition of any gearing or chain;

Front Wheel Brake: So according to Regulation 9.(1)(a), as the the pedals of a Penny-Farthing are affixed directly to the wheel to drive it in the absence of gearing, then negative resistance on the pedals is the only braking mechanism we require.  As a practical matter, it would be highly undesirable to have a mechanical brake on a Penny-Farthing's front wheel in any event due to the risk of doing a "header" and going over the handlebars if such a brake was applied too quickly and/or aggressively.

Rear Wheel Brake: Although a braking mechanism is not required by law as the small rear wheel is not driven by the pedals or gearing, Penny-Farthings DO have at the very least a rear brake: the rider's heel. This is achieved by the rider standing on the mount peg and applying their heel to the rear wheel. This method may sound crazy, but it's proven and has been in use as a braking system by Penny-Farthing riders since the beginning. Newer, modern Penny-Farthings such as the UDC MK 4 ship with a calliper brake on the rear wheel. Nonetheless all PF riders should familiarize themselves with technique of braking the rear wheel with their heel!

Testing & Inspection of Braking systems by Police: Regulation 11 of the same statute provides the mechanism for the Police to inspect any cyclist's brakes are legal. Police as a general rule do not randomly stop cyclists and checking their brakes. I expect the Police will do so if you are either involved in an accident or they observe you cycling out of control.

To learn more about Penny-Farthing braking mechanisms, go HERE

Rear calliper brake on a UDC MK4 PF
Lights & Reflectors:
"The Road Vehicles Lighting Regulations 1989" governs the lighting cyclists will be required to have. The "Explanatory Note" section of which details that "sunrise" and "sunset" now replace “daytime hours” and “hours of darkness” which included a half hour before each. Thanks to @thelawnet for the correction- well spotted!
I ride my Penny-Farthing frequently at night, so I not only meet the legal minimums for lights, I seriously exceed them. ;-)

Lights: Lights are NOT required when cycling in daytime. HOWEVER: If riding your Penny-Farthing (or any bicycle) between 30 minutes BEFORE sunset and 30 minutes AFTER sunrise, it must have:

Front Light STEADY: Light must be WHITE in colour and emit STEADY light OR

Front Light FLASHING: Whether a flashing light is approved depends upon whether it has additionally has a steady mode. If NOT, a flashing light CAN be used IN LIEU OF a steady white light.  If your flashing light DOES have a steady mode, then it's only approved if it conforms to BS6102/3.

One flashlight set to steady the other to rapid flashing

Rear Light: RED rear facing light affixed to it. NOTE: I bought a red rear light that incorporated a reflector in it.  So even if the batteries died while I was riding at night, the reflector would STILL work.

Note Rear Red Light incorporates a reflector that works even when light off

The spine is too thick for most light mounts I got around the problem by using a silicone band bought on Amazon to attach; works perfectly.

Reflectors:

Pedals: Required to be fitted with amber reflectors.
Rear Reflector: A RED rear reflector required to be placed between 250-900mm from the ground. My rear Red light incorporates a reflector, so killed two birds with one stone
OPTIONAL: I put strips of silver reflective tape up the back of my Penny-Farthing's spine. Doesn't look bad and anything I can do to increase visibility I will do.

Bells:
I couldn't find any reference that states a bell is a legal requirement, but you'd foolish to cycle without one. And if it's true that it's a legal requirement to SELL bicycles with a bell (haven't been able to track down a link to this yet), the odds are you already have a bell anyway...
EXCEPTION: Northern Ireland: a bell IS a legal requirement in NI, unlike the rest of the UK.
Cycling on Drink or Drugs: Highway Code Rule 68
If you toodle home from the pub pissed on your Penny-Farthing and are caught in such a condition by the Police, it can attract a £1000 fine. Although technically your vehicle license can't be endorsed with points or directly lost for cycling unfit, you could still lose your vehicle license.
And if you are involved in an accident, I'm sure whatever cycling insurance you have will likely be invalidated.
Who doesn't like toodling to a pub on a their Penny-Farthing for a pie and a pint? Just take care not to over-do it...
Insurance:
Unlike a motor vehicle, cyclists are NOT required by law to have liability insurance. HOWEVER, strike some pedestrian who steps in front of your Penny-Farthing listening to music with their earbuds and you'll wish you did. And stopping a Penny-Farthing is a bit more challenging when responding to the presentation of a hazzard.
Important Considerations:

EXCLUSIONS to Look For: If the policy excludes direct-drive cycles- ones where the wheels are not driven by gearing as with a "safety" bicycle- then your Penny-Farthing would NOT be covered.

Cycle Appointed with all Legally Required Safety Equipment: Ensure all the lighting, braking, and other safety equipment required by law is present and working condition. If the Police inspect your Penny-Farthing (or any cycle) after an accident and anything is found amiss, I suspect an insurer will jump at the opportunity to deny you coverage.

Group Insurance vs Personal Policy: Many cycling organizations offer liability insurance with certain memberships. Getting group cover via an organization is less complicated and will likely provide better cover with fewer exclusions than taking out an individual policy. Also, if you can support organizations that advocate for cyclists, why not?!?!?

I emailed British Cycling- who provides my liability insurance with my "Ride" membership- and directly asked them:

I ride a Penny-Farthing- which is legal to ride on the UK's public roads.  However, this is a direct-drive bicycle- the pedals are affixed to the wheel and drive it directly in lieu of gearing. Is this covered under my membership liability insurance?

They replied IN WRITING to this question that it WAS:

Yes I can confirm you are covered on a penny farthing.

So now I am 100% bullet-proof if anything happens.  I'd suggest asking for such a confirmation before agreeing the policy so there's not grief later if you're involved in an accident riding your Penny-Farthing.
So I can confirm AT LEAST British Cycling DEFINITELY provide Penny-Farthing cyclists liability insurance with their "Ride" membership.
Addition sources consulted to prepare this answer:
In addition to the other links, I've consulted the below sources:

https://www.cyclescheme.co.uk/community/featured/cycling-and-the-law
https://www.cyclinguk.org/article/whats-legal-and-whats-not-your-bike
https://www.cyclinguk.org/cyclists-library/regulations/construction-use
https://www.cyclinguk.org/lighting-regulations


Getting a framebuilder to put horizontal dropouts on the Boardwalk looks quite possible from a quick glance at the picture. On the other hand, it looks as though it has fairly conventional geometry so you may find that a current bike with hub gears off the shelf works for you. It's likely to cost more than $300 to get new dropouts fitted since you'll also be stripping and repainting the frame. Since it's alumnium and most framebuilders work with steel you might struggle to find someone who can do the work.

An alternative is to fit a hub and use a derailleur or chain tensioner to take up the small amount of extra chain you'll need. chain tensioners are common on singlespeed bikes for the same reason as you need one (and singlespeed conversions are very common). This will be the cheapest way to fit hub gears to your current bike.


I would suggest your frame may be a bit small for you. I'm slightly shorter than you and I have a Scultura 906 in a 54 cm frame (size on the frame sticker says S/M). The longer stem may assist, however it may put you in a more race position which could lead to the neck pain. As for the calf cramps this could be a couple of things; 1) seat height too low, 2) lack of magnesium.

To check the seat height, hop on the bike and put the pedals at 12/6 o'clock. Rest your heel on the 6 o'clock pedal. If your leg is fully extended your saddle height is probably correct. If your knee has a bend then I'd suggest raising the saddle height until the bend is gone.

As for the magnesium, that comes down to trial and error.

On the neck pain, I'd suggest seeing if you can lift the stem (if your fork steerer is long enough) or maybe flip the stem to give yourself a little more height at the front of the bike.

As always, when doing a longer ride, make sure you're staying hydrated, as that is the only thing that causes me headaches when I ride a long distance. Too much heat, and not enough fluids. Let us know how you get on.


ergonomically sound seat types or features?

Yeah, seat height and fore/aft position (and handlebar position) are more important than design.

Seat height is especially important for knee pain -- having the seat too low is quite hard on the knees (as is pedaling in too difficult a gear).

For the back, seat position fore/aft and handlebar position (both up/down and fore/aft) determine how much the back is stressed.  Generally a more upright position (seat and handlebar closer together and handlebar higher) is easier on the back, but seat and handlebar too close together can "scrunch up" a tall person and cause problems.  (And if you have an excess of avoirdupois having the handlebar too low can make it hard to breathe well.)

The main thing that seat design can do for you is relieve (or not) pressure on sensitive areas, indirectly relieving the back since you don't contort yourself so much to take pressure off the sensitive areas.  But it often turns out that super-padded seats and (especially) seats that are extra wide are less comfortable than their more Spartan cousins.


If you want something that really is absolutely puncture-proof:  http://www.greentyre.co.uk/bicycle-tyres.php

But they are extremely hard work to fit and, more importantly, they combine the harsh feel of a small hard tyre with the high rolling resistance of an underinflated tyre, and they lack grip. (At least that was my experience with some 700c ones years ago; they might have improved, but I doubt it. But I was getting punctures several times a month until I fitted them. I went back to standard tyres when I changed my commute route. The Marathon Plus wasn't available then.)

Review of another similar puncture proof foam filled tyre (doesn't have a 20" size available, but gives a second opinion on the merits of such tyres): http://gearjunkie.com/flat-free-foam-bike-tires

For normal pneumatic tyres Marathon Plus is about as close to puncture proof as you can get. They can be quite stiff to get on and off though (nothing like as bad as the GreenTyres though).

http://www.londoncyclist.co.uk/why-do-boris-bikes-hardly-ever-get-punctures/

There are other 20" tyres with a puncture resistant belt, the Primo Comet for example, or the Panaracer Minit Lite "PT Shield", or the Marathon Supreme (lighter than the Plus), but I don't know of anything else as resistant as the Plus.

It won't really protect against pinch flats though. Either teach your friend to check her tyre pressure and use a pump, or do it for her.


My SRAM X3 rear derailleur will only shift to the lowest gear but won't shift back higher

Highly likely that friction or pinching of the cable in the housing is preventing the derailleur spring from pulling the cable when shifting from large to small sprockets.

Remove the cable from the derailleur, With the wheel out and the cable detached check that the derailleur moves freely.  Pull gently on the shift cable (you may need pliers to hold on to it) and work the shifter, on upshifts the cable should pay out smoothly with little resistance.

Check the shifter cable housing run for kinks, tight turns etc.


Stopping is relatively easy - the rearmost foot is pressing back/down on the pedal to operate the brake, the other goes on the ground. If you're used to two feet on the ground when stopped you'll need to practice stopping with one foot first. You probably need to swap anyway, so the foot on the pedals is ready to push down when you move off. It's vaguely annoying but you'll get used to it.

To shuffle the pedals around while stationary you need to be pushing gently as if you're trying to pedal forwards, while rolling the bike backwards. Again, it's annoying. When I ride a bike like this I quickly get a little system organised so that I stop, rotate the pedals forward to disengage the brake and get ready to move off, then roll back a little until the foot that's on the pedal ready to start is in the right position.

I do think you should fit a front brake of some sort just for safety. Braking with the rear wheel is less effective, especially in an emergency stop situation. Even a cheap caliper brake is better than nothing (and often that's all those bikes are set up for).


The CAAD10 disc frame uses 700c wheels with standard hub spacings (135 mm rear, 100 mm front). The width of the rim  you should choose depends on the size of tire you intend to run (which is limited by your frame). It looks like the bike was originally spec'd for 700x25 tires. Based on other Cannondales, I'd guess this is somewhat tight to begin with, but if you're lucky you might be able to run 700x28's. So, pick the rim width accordingly (likely 13-17 mm).

I'd suggest buying complete wheels (or getting a wheel made by a competent wheelbuilder, who should work with you on selecting appropriate rim+hubs+spokes for your needs). Note that you need disc brake hubs on a CAAD10 disc, and your rotors have to be compatible with the hub (or you have to use an adapter).

Often, you can't get the exact parts spec'd from OEM's (there are lines of parts specifically for OEMs). But its not hard to find equivalents or improvements for around the same price (even if you can get them).

Note that a decent number of wheels (especially cheaper ones) need some adjustment before they're ready for the road (even if they're brand new) -- you'll likely want to use a bike shop for this.


Wrapping alloy brifters for cold weather

Do you care about originality ?  Consider changing the brifters for something made from plastic or carbon because as you've noted, they don't suffer the same issue.  Likely to be an expensive solution.

So, can you paint your brifter's outside surfaces with an acrylic enamel paint?  you'll need many thin coats to build up a thick layer that won't abrade easily.  Sand between coats and add some clear coats as the top layer.  Avoid painting "under" the brake lever where it faces the gear change lever.

Instead of paint, you might choose to use a product called Plastidip, which historically was used for dipping tool handles, but more recently comes in a spray can and has been used for car wheel rims, etc.  This stuff comes in multiple colours.

You can also get sticky-backed cork tiles/sheet which is under 2mm thick.  Some creative pattern work and you should be able to put some heat-insulating cork between you and the cold bits.  Do apply sealant/varnish to the cork to protect it from the cold.

Leather is another valid alternative to cork.

Finally, you wear gloves already, so assume they are full-finger.  You could add heating wires to the gloves and run them off a small USB battery in your back pocket, or add heating wires to the brifters themselves and mount the battery on the bike frame.

If you do get a choice of colour, I'd suggest black, or as dark as possible to increase heat insolation from any sunlight.


Can l add more gears by replacting the cassette on my mountain bike?

To do that you need to change the shifter and derailleur as well.
Different brands, and different numbers of cogs on the rear require different amounts of pull on the gear cable to shift one gear, and the cogs, chain etc are all different sizes. This also means that the total cable moved to get from highest to lowest gear is generally also different. Note that it's usually specified in tenths of a millimetre (0.1mm), so everything has to be quite precise. Otherwise the bike won't stay in gear.
While you can change everything over like this it's generally more expensive than selling your bike and buying a newer or higher spec one with the new groupset on it. If you can find a damaged bike with the necessary parts intact that's likely to be the only cheap way to make the change.


Most of your chamois creams/"butt butters", such as Paceline's "Chamois Butt`r", are fairly conventional combos of standard skin cream ingredients, with a heavy emphasis on lanolin.

I've never tried petrolatum (though many swear by it), and I'm a bit skeptical as to how it would fare compared to the more skin-cream-like concoctions.  Plus it would make more of a mess of the chamois and be harder to launder out.

I'll admit that the commercial concoctions are a bit expensive, but a little goes a long way, so it's not that big of an investment.


Cycling traffic signs and rules in Germany

You might consider contacting the ADFC (Allgemeiner Deutscher Fahrrad-Club). It is an association specifically for people who cycle as a means of transportation (rather than as a sport - though of course the two are not mutually exclusive).

They are part service organization, part environmental organization. They have local groups (Kreisverband / Ortsverband) in almost every city, which usually have regular meetings. Contact your local group (or just go to the local meeting); they will be very happy to give you hints, share local knowledge etc. (even if you are not a member yourself).

Many local groups even have explicit meetings for people new to the area, or new to cycling in general, where they try to pass on useful knowledge.

For a list of local groups: ADFC vor Ort

They also have a lot of general information on their website. See e.g. Sicher unterwegs.

Note: Most stuff is only available in German, but I hope basic German is enough to read it. Local groups will be German as well, but many people will speak some English.

Disclaimer: I am an ADFC member myself, and have been active for several years.


Because you are buying new brakes - the best thing to do would be to store your old brakes in the same manner you receive the new brakes.

And that would also be re-using the existing packaging.

I'm sure the logistics in getting newly manufactured brakes from the production line to the retail counter / customer involves many months of transportation and storage. So you should be absolutely fine mimicking this.


Is it possible to replace a 1 1/8 steering tube with a 1"?

I'm going to recommend that you NOT do this.

There were in the past manufacturers of 1" steerer suspension forks - though I'm not certain that they're are still sold. It is important to note that bicycle frames built to accept solid steel forks have different geometry than those built for suspension forks. The frame is designed for a fork that doesn't have suspension travel - the head tube is taller, the down tube and top tube are welded to preserve the set geometry of the bike. Installing a suspension fork would lift the front of the frame up and slacken the head tube angles - overall, I suppose it isn't a huge deal...HOWEVER...

If you're having a hard time finding bike parts, will finding a 1" steerer tube, a suspension fork that has a brazed steerer tube, a bushing that is machined to fit precisely and a machinist to make your bushing, and someone to braze this all together be any easier than finding a more modern bike frame or a used 1" suspension fork?

You might be able to remove the steerer from the suspension fork if it is brazed in, but retrofitting a new steerer tube will require a bushing machined to VERY precise tolerances to allow for heat expansion and brazing filler flow. Any valves, adjusters, stanchion caps...anything not brazed or welded to the fork crown will have to be removed to prevent any damage while heating. You'll want this done professionally because a failure while riding would be regrettable.

With the amount of work involved, it may be more cost effective to track down a mountain bike frame with a 1-1/8" suspension-ready head tube or just have someone replace the head tube in your existing frame.

Also, it may not be too difficult to find an affordable bicycle in Argentina. Here is the distributor for Giant bikes in Argentina. You can email them at: info@giant-bicycles.com.ar. You can locate Giant vendors by province here. If Giant is represented there, you'll likely find other companies and reputable bike shops who can order you frames, parts, bikes, you name it.

Added info:

Here is a forum thread detailing fork building. The most important point is the fit of the steerer to the crown. If it is too tight, the brazing filler won't flow evenly and consistently, too loose and the integrity of the braze is compromised. If you do decide to do this, definitely try it more than once. The first two or three you should cut up to inspect the brazing filler flow (cut lengthwise and try to pull the pieces apart. Bubbles, seams, and burnt flux are all signs of a poor joint.) There is a comment about brake bolts and wedges being used to prevent steerers from pulling out of the crown, but I wouldn't risk it.


Converting 3x7 to a 1x7. Is it possible with only existing parts?

You have a zero cost solution, which is to keep the front derailleur but remove the cable (and shifter if you like). Then use the FD limit screws to fix it in the right position to act as a chain guide.

You don't need a 1x chainring, in fact using one with a 7 speed chain is probably less than ideal, so you're actually better off sticking with an existing chainring. You may not be able to get rid of the big chainring, or you may need to get shorter chainring bolts if you do, depending on how the big and middle rings are mounted.


How to avoid or reduce back-pain by adjusting the handlebar and seat of 19.5" MTB?

I'm 6'2" and my Giant XTC 29er XL (22") fits me perfectly. I would definitely upgrade. There's more to the geometry than just the height of the saddle that could affect the way your body fits (or contorts to) the frame.


Chinese carbon clinchers - cheap but safe?

First of all, you need to rid yourself of the idea that "It can't be top-notch if it's made in China". Don't let all the cheap junk that comes out of China make you think they don't manufacture top-quality products.

When you buy Zipps, you're not just paying for the decals... free-market competition sees that this doesn't happen, at least not much.

Name-brand stuff is generally a bit more expensive, not necessarily because the brand can get away with charging more, but because the product generally passes through more middlemen, partially due to said name-brand being less specialized.

If someone is selling "just like Zipp" wheels for $500, corners are obviously being cut. But if they are asking $1500, chances are they're probably just about as good as the Zipps.

If there's no brand name at all, that's a bad sign. They're trying to avoid accumulating a reputation. I would never buy anything new if they didn't at least have an (English) website.

So to sum it up, if the wheels are significantly cheaper (like $500), they're either heavy or dangerous. Or both.

If the price is believable (more like $1500), it may be worth it if you do a bit of a background check on the company.


What parts do I need to use Di2 wireless shifting on a road bike

You require these items, all DI2 compatible:

rear derailleur mechanism
di2 controller box (normally strapped to the bottom of your stem)
di2 brifters, or di2 shift buttons that strap to your handlebars, but mean you can keep using your brifters as plain brakes.
battery (one for a wired system, or several for a wireless system)
wiring harness, and secure method of holding wiring on/in the frame so its protected.
wall charger (maybe USB based, maybe a separate wall charger)

You probably require

front derailleur mech unless you want to make it a 1x bike

For your testing, you really will need a road bike too.  The derailleurs will try to calibrate themselves and may go into fault mode if there's not a cassette or chainring detected.   So that means a modern cassette with 11 gears, maybe 10 (I'm unsure on this point)

Generally speaking, the whole groupset will cost about the same as a bike with that groupset fitted.  Used bike gear drops in price very fast too, so don't think you'll get your money back by selling it on after the testing, even if its never been ridden.

An alternative suggestion might be to make contact with the Shimano distributor in your area and see if you can get access to test/demo kit for your purposes.  As long as you're not cutting out a reseller, they might be happy to talk.  Or involve a LBS


There is a front-end trike conversion system called the Newton that has been used for tandems. I have no direct experience with it.

There are a number of rear-end trike conversion systems that are all similar in design: the Trykit and Longstaff. I know that Longstaff has built tandem trikes from the ground up, although I don't know if their conversion kit is suitable for tandems.

You may note that these companies are all in the UK. Triking is much more established there.


Are there penny-farthings with an internally geared hub?

Yes, there exists at least one which was made/improvised with a Schlumpf Innovations bidirectionally-fixed internal-gear unicycle hub.  If I recall correctly, it had a 36 inch unicycle wheel, giving an effective diameter in high gear of around 54 gear inches, fairly typical for larger penny.
The structure and silhoutte of course were odd, with the relatively small physical wheel it might be termed a "mini-penny", the actual fork was an old Nimbus Nightfox unicycle frame squeezed to fit the 100mm bearing spacing of the Schlumpf hub vs the 125mm spacing of the Nimbus Unicycle hub it was designed to hold.
Edit: build description from the creators, alas, no pictures.
There also is/was the "bicymple" which has a fairly small difference in wheel size for a "penny" but does have the bigger wheel up front. It freewheels, but one of the models incorporates a freewheeling version of the Schlumpf hub.


Carbon frame that is designed for strength and durability rather than lightness?

Why produce a heavy but durable carbon frame if one can have a heavy and durable steel frame that is cheaper? Apparently there are no (mass) buyers for such technology.

The bicycle industry is mainly driven by the competitive cycling needs, whether it is good or bad for a regular consumer. The choice of frame material is driven by the material properties and many adjacent tradeoffs, such as durability/weight. The resulting product price is closer to the end of the list in competitive disciplines. The product will not be initially mass-marketed in any case, which would drive its price even higher, but who cares.

At any point in time, current technology advancements dictate the sport's favorite frame material. Movement from steel to better steel, then to aluminum alloys and then to carbon was caused by that. If tomorrow someone invents how to make a frame from weightless forcefields, it would quickly replace carbon in sport.

The consumer market is more driven by a mixture of price and fashion trends, in no particular order. What is deemed to be well sold, will be produced. What does not look like a marketable thing, will only stay at bike expos and end up in museums. Apparently there is no need for carbon frames that are heavy — there are already steel frames. Besides, what's wrong with modern consumer grade carbon anyway? Its advantages and weaknesses are well known, and, if used properly, carbon has no life length limitation.


Get yourself some Clean Streak degreaser and a dental pick. Gently work the pawls until they snap back into place firmly. Then use the compressed air to clean it out and put a drop of thin chain oil onto the pivots. That should get you going.


Should be perfectly safe.  I actually did a similar thing on my road bike to allow a little more cushion in the rear, for my rear.  The only hassle I can see is if you have to carry two different tubes.  Can't remember off the top of my head if you can get some that span those two sizes.


Can tire sealant be used in anti-decubitus cushion?

I'll do my best to help with my knowledge of sealant, and this was too long to comment.

Sealant MIGHT work.... but it may cause more issues than it fixes.

My main concern would be getting it from cell to cell, as in a tire or tube it is easily distributed along the entire tire/tube, whereas this look would take some work to get it all the way to the other corner from that of the valve. Also it depends on the size of the hole or puncture as sealant is made for relatively small holes. (1/4" to 1/8" depending on brand)

Also it may impede air from getting to some of the cells if it gets clogged up, it's hard to tell how large the airways between the cells are from the image.

The other kicker is sealant does not last forever, in a tire or a disposable tube it can be removed if it begins to clump or harden, or the tube can be easily and cost effectively replaced. Where as this, you have said is semi-expensive so if the sealant clogs some of the airways and cells no longer inflate you are kind of stuck with a defective cushion that will then put more pressure on certain areas.

Further more there is not much to get it to the top of the cells, so it will collect in the lower regions, and if there is a puncture near the top of a cell, may or may not do anything.

If you have an older one you can try it on without losing too much i would try that. Otherwise it may cause more frustration than it fixes. Hope this helps.


Can i use a XT 8000 crank instead of GRX crankset

A single ring is quite easy because there is no front derailleur to worry about.
I assume you have FC-RX810-1, which has 110mm BCD, and uses the same chainrings as FC-RX600-1
Wolf Tooth go to 36t https://www.wolftoothcomponents.com/products/110-bcd-asymmetric-4-bolt-for-shimano-cranks
There are some Chinese 34t chainrings as well
https://www.aliexpress.com/item/4000620134076.html
If you want to swap a XT crank you can but you will need to remove (or replace) your BB and fit 3x 2.5mm spacers  https://si.shimano.com/api/publish/storage/pdf/en/dm/MBFC001/DM-MBFC001-01-ENG.pdf
Then your XT crankset will have slightly (0.23cm) wider chainline and substantially (2cm) wider q-factor


How do you wrap a bicycle frame with used inner tubes?

I tend to use zip ties - they're very strong but can be replaced/moved without damaging the tube.  Also for extra damage prone bits (chainstays, BB tube, etc.), I sometimes use the tyres.


Total brake failure - trying to understand what happened

Since recovering from my crash, I've put a bit more thought into this.  I replaced the calipers, rotors and pads, with Avid BB5s - so very similar to the Promax ones that were essentially copies of the same design.  The Avid ones make it slightly easier to tweak the fixed pad, and this turns out to be a good thing.
Fixed pad wear makes other issues worse: One thing I've since noticed with BB5-style brakes is that they're quite sensitive to the fixed pad position, and therefore to fixed pad and rotor wear. This makes other issues worse, and unlike getting them filthy, gets worse the more you brake.  Riding in mucky conditions it's important to check and set the fixed pad clearance fairly close periodically.  This certainly wasn't the only cause of my crash, as seen from the melted material in the rear rotor, but I think it goes some way towards explaining the uneven moving pad and rotor wear at the front.  On brake with only one moving pad, the rotor is bent to contact the fixed pad.  If the fixed pad and/or rotor (in my case, certainly both) are worn excessively, the necessary bend increases, meaning two things: more of your braking effort goes into bending steel; the contact between the moving pad and the rotor is concentrated nearer the axle, producing the uneven wear in the photo above.  With slow wear this should be a small effect as the pad will take on a small taper, but if things wear too fast (or you somehow back the fixed pad off instead of driving it further in) this either won't happen fast enough, or it will wear down to the backing.
On the Promax brakes, adjusting the fixed pad with the wheel in was tricky - there was a knurled plastic part to turn by hand but the adjustment was too stiff (so I was used to thinking the adjustment had bottomed out when it hadn't), meaning using a less than ideal screw in an awkward place.  The BB5s adjust in the same way but nicer.  I'd checked and tightened earlier in the day, in daylight, but everything was wearing so fast (though I didn't know it) that I gave the fixed pads another tweak not long before the problematic descent, this time in the dark.  At the front it still wasn't enough.
Conclusions:

I'm personally not going near "ceramic" pads again: this bad experience; they seem to wear rotors very fast; and the description is fundamentally not to be trusted if they can melt.  For some people they might work.
Check the fixed pads frequently.  If braking seems soft, stop and tighten, perhaps also cleaning the rotor (pre-injection isopropanol swabs are good for this).
If you run out of travel, fit new pads immediately.  Wear is very dependent on riding (weather/surface) conditions as well as road surface and load, so you can run out fairly suddenly.  Range of adjustment determines when the fixed pad wears out, so it can look like there's plenty of material when the pads are no good (much more than for the moving pad). I always carry a spare set (since an earlier issue which in hindsight offered hints about pad wear) and have changed them at the roadside, mostly recently coming back from a 2-day 200 km tour with rain, mud, steep hills, and gravel (and a record 4 punctures in 2 days).