Find out where long distance/endurance riders stopped to sleep, from spot trackers?

If you look at the riders who do well in these events, of course they don't sleep much, but beyond that (and not wasting time*) they don't have so much in common though I can think of a few examples where the winner skipped a night early on and kept that lead. Some sleep sooner but shorter. Crucially they only sleep when they really have to, and know enough about what they're capable of to understand how much sleep to get, so:

Planning for a good spot isn't relevant (except basic safety) as you'll want to be too exhausted to care.
Trying to go as far as last year's winner before the first sleep takes no account of different riders or differing conditions (riding conditions e.g. headwind, and sleep conditions  e.g. shelter/not freezing).
Trying to go as long (time) might be better but you won't find that on a map and it still doesn't help with rider differences.
You don't want to nod off on a bike and wake up by crashing hard (though drifting off the road and waking up propped in a hedge seems fairly common).

Of course your sleep kit is inter-related with your sleep strategy - is it almost instant to use? good enough for every night but heavy? only fit for emergencies and catnaps?
Successful riders' own words probably help more than the data. A few examples I've come across that discuss the sleep aspect in some detail

Where there's a will by Emily Chappell (TCR '16 first woman).  Award-winning and recently released in paperback.
I've heard Ian Walker (North Cape 4000 '18 winner) talk about it, probably in this lecture
I heard an interview with Fiona Kolbinger (TCR '19 winner) but can't recall where.

*One I've heard in various versions - if you're not riding, sleeping, or eating you're wasting time.


How to narrow down choices when finding a new bike?

As someone who has recently done the same thing, I'll think I can help with this.
The biggest trap I fell into was overthinking it.

Some of this might sound a little backwards but it's my thinking at least.
As a starting point, you need to work out your budget.  No point considering anything that's outside that.
Sounds like you already have your intended use sorted, but that's a pretty big thing to nail down
Next thing I would suggest is pick an pick a bike shop that seems to know what they are talking about and not just flood you with marketing jargon.  Find out what sort of follow up service etc they have.  As a starter, you're probably going to need some help with setup & maintaining the bike so pick one who will.
After that, take a couple of options from that store in your budget for a ride, see what you like.
Then buy the bike.


Possible to utilize magnets only to spin a bike front wheel for a longer duration (less drag)?

sadly, no.
You cannot use permanent magnets alone (it's a physic impossibility, a consequence of Earnshaw's Theorem). You need to lawyer your way out of it, which you can do either by removing "permanent" (i.e. employ active electromagnets also; this is what is commonly done with magnetic suspensions for lamps etc.) or by removing "alone".
it has been pointed out to me that Earnshaw's Theorem only holds with ferro- and paramagnetic sources. The addition of diamagnetic materials does allow stable configurations with permanent magnets alone. Werner Braunbeck's trick, though, only holds with diamagnetic materials, and those have a strength that's whole orders of magnitude below high-flux rare earth ferromagnets. So, unless the wheel is large enough to support a half ton of diamagnetic bismuth shield, I'm afraid passive levitation isn't a thing for bikes.
Earnshaw's Theorem actually applies to a whole class of forces, so you can use no combination of those to wiggle out of "alone". No electrostatic fields, no gravitational fields. You're pretty much left with superconducting pinch-effects and, again, mechanical bearings (you can replace a mechanical bearings assembly with permanent magnets as long as you keep at least one bearing).
You could have a spokeless, hubless wheel where the weight is borne by magnets between an inner rim and the tyre, with mechanical bearings to keep the two rims aligned (the bearings would only be subject to lateral forces). This allows the magnets to spread out the weight and thus exert a minimum force.
And at this point you need to keep grit out of the space between the magnetic poles. You need a seal, and that's going to need to be mechanical, and problems with friction will resurface. Also, the magnets will be heavy. A toroidal N41 magnet, circularly magnetized (north pole in the hole, south on the periphery), 4cm wide, 2cm thick and 5cm of inner radius, weighs about six kilograms; you need another wider segment to stay above, and that will probably weigh two to three kilos; this will get you a repulsion of around 200 kg, i.e., unless you thrust 2000 newton of force downwards, the magnets won't touch. One advantage is that it will double as suspension. A big disadvantage is that anything magnetic will be attracted to the hub with great force (you can harm yourself pretty severely with those kind of babies).


I'm going to point out the features that make it a 70s bike.

Cottered cranks.  They went away in the late 70s.
3-leg spider in the middle of the cranks - that's old looking, but the thin cranks imply a racer.  Do get it off the ground, you're damaging the big chainring like that.

And these are the aberrations:

The cable stops on the top tube - most bikes used a full brake cable housing with clips, not an exposed inner cable.
No lugs - at least none visible in the photo.  This looks like a smoothly welded steel frame.
Down tube derailleur seems to have a thing under it - is not overly clear in the photo.

The saddle is too new, and there appear to be no wheels, but its very close to being complete and rideable.  You need a new chain and new brake pads too.


How long should a bike last before the wheels wobble?

It is normal for a wheel to have an initial break in period.

As you ride the bike, each spoke has its load released, and retensioned each time it passes around the bottom of the wheel. Since some parts of the wheel are aluminum, and others are steel, the aluminum parts compress. This means that the spokes are not under as much tension as they need to be.

Since not every spoke will compress exactly the same amount, it makes some spokes looser than others.

A wheel's strength comes from having the spokes act like the wires of a suspension bridge. As long as they are under the correct amount of tension, and the tension is equal on each spoke, the wheel will stay straight and strong.

A single loose spoke will allow a wheel to detension, and come out of true. If you ride the wheel in the detensioned state for any length of time, you can damage the rim, and make it impossible to make the wheel perfectly straight, round, and strong again.

This process of break in takes different periods of time for different wheels and different riders, but most bike shops recommend a service on the bike within 30 days of riding it the first time. That should include a wheel service.

Six months is too long to expect them to fix it free, although they might do it to build good will with a customer of theirs. I would not go in and complain, but do go in and ask them to explain why it happened. Make sure you speak to a professional mechanic or manager, and not the high school apprentice mechanic.

Be friendly about it, and a good shop will likely fix it, if possible, without charging you. At the very least, you will get an idea of what kind of shop they are, and a real idea of it is repairable or needs to be replaced.

I hope that helps.


We found it!  Somehow it came to Marlyand by way of Barcelona! http://www.barcelonayellow.com/bcn-transport/78-bicing-city-bikes


Is it necessary to reinforce a carbon fiber steer tube?

There is absolutely nothing about requiring a compression plug inside the carbon fiber steerer in Trek's owner's manual.

Given the plethora of warnings embedded throughout that document, I'd say such a lack is definitive.  So, despite it being impossible to prove a negative, umm. no:

In general*, carbon fiber steer tubes do not need to be reinforced with a compression plug.

The myriad of compression plugs available support this assertion.  There are plugs that cover the entire inside of the tube from just a few mm under the cap down well past the stem.  There are plugs that reach down only a few mm total.  There are plugs that "hang" down inside the steer tube several cm from the cap before a short plug grabs the steer tube for a cm or so.  If the plugs were in general needed to support the steer tube, they'd all be longer than the 3 cm or so length that stem clamps onto the steer tube.  And user manuals would have warnings not to put too many spacers on the top of the stem that would prevent the compression plug from being located properly.  The Trek user manual linked above has no such warnings.  It only states that there must be at least one 5 mm spacer above the stem.

* - because there's going to be one out there somewhere that does say it's needed...


Bug Repellent for Mountain Biking that won't melt my gear?

Check if icaridin (Wikipedia) protects against disease vectors in the region you would like to bike at.

Icaridin is less damaging to synthetic materials, less sticky, and repels many types of insects (and arthropods).

Icaridin also has down sides, for example, it may not be adequate for some disease vectors and a single application does not protect as long as DEET does.

Please note, that these draw-backs are particular relevant for 7% solution of icaridin. Most comparative tests that find an equivalent effectiveness of Icaridin to DEET use a 20% solution. The latter may not be available as a commercial product in your country.

The topic effectiveness of insect repellents is also covered on (travel) stack exchange.


It's a little hipster-ish and affected, but tucked between your belt and your back/hip is actually the most secure & reliable U-lock carrying solution of which I am aware, and is actually much more comfortable than it sounds.  Just push the loop side down in between your belt loops, and the lock bar will prevent it falling through if you just cinch your belt up a little bit.  It's a quick and easy solution that won't wear out until your belt does.


It is most likely a carbon crack.  Either way, do not even ride it down the driveway.
The awesome news is that trek warrants that and you can expect a replacement.


What is the cost saving from manufacturing bikes in China vs USA or Taiwan?

I think my rough estimate would be 10 to 15%, although an argument might be made for less taking into account markup.  Cannondale was one of the last big manufacturers to produce all their frames in the US.  We carried them in a shop I worked at during the time they transitioned over.  Basically, one year all their bikes were ten to fifteen percent more expensive than their comparable counterparts (Trek, Specialized and Kona at the time in this particular shop) as it had been since I worked there.  The next year the prices were more in line with the other manufacturers and the frames had "Made in China" stickers.

I have checked in the last few years, but some manufacturers used to still build their highest end products in their home country.  Beyond the big manufacturers there are still many smaller or custom builders active and alive in the US.  If you look at the pricing differences between a litespeed, seven or lynskey and a major manufacturer, you may get an idea.  But you may also choose simply pay that higher price and get a bicycle that was for sure designed and made here in the US.


Can and should one install rivnuts into an aluminium frame?

I would recommend you not do this.  I have first hand experience with drilling holes in frames, albeit only one hole.  Although it was a success, the situation was different.
The short version...on two separate bikes, I drilled into the seat tube to allow for a dropper post routing.  I have had no trouble.
I did my homework, considered pros and cons, and most importantly considered the cost of ruining the bike.  After drilling, I would ride it and then inspect it, gradually increasing the amount of rigor of the test, to the point that I was going over jumps and landing flat.
Other posts suggested that there could be cracks that I don't see.  It is possible, yes, but based on the amount of abuse this bike has gone through, I feel like if it were going to fail, it would have failed by now.
Your situation is different, you would need two holes, and they are proposed on the downtube, where there is more stress.  If you have a butted frame, the material is thinner in the middle, right where you would want the holes to be.
I do not think the rivnuts will add strength to any holes you drill.  This might be the case if it were a perfect fit, and welded in with no voids.  But that is not the case.  They are not designed to add strength to anything, just to add threads to something that is already plenty strong.
You will not be able to figure out how think the material is without drilling into it, at least not that a layperson can do.  I expect someone scientist with the right xray or ultrasound could do it, but practically speaking, your guess is the best you can do.
I would suggest a similar approach to what another user mentioned.  But here is how I would do it.  Cut a strip of old inner tub, about 2 cm wide.  Wrap it around your frame once or twice where you would have wanted to drill the holes. If you want to glue it on there, you can, but you don't need to.  I'd suggest Barge Cement, just do it outdoors, that stuff has some pretty serious fumes.  Now just zip-tie the water cage on there, nice and tight.   If the zip tie slips of the spot on the water cage where the bolt would go, just bend a little lip into it.
Lastly, I get the hunch you are the kind of guy that likes to tinker with stuff.  Me too.  In this case, I would suggest your tinkering skills with drill bits would be best applied somewhere else.


The jagged and uneven edges you are seeing around the straps are merely cosmetic. At best they are at the minimum tolerance for manufacturing quality and at worst are an isolated case of tolerances going wrong during production.
Either way, as long as the integrity of the foam in the helmet is not compromised (by virtue of crashing or the like), then it is safe to use. Happy riding!


Regarding the picture: in the comment I said the rider isn't going high because of not trying hard enough, but on second thought the main reason for not being able to get proper air from such jump is that the lip is not steep enough; in fact the entire transition of that jump is rather mellow and not suited for height, you'd almost have to bunny hop out of it to go higher. The second jump on the pic seems better in that regard though it is hard to tell. For reference, something like this will launch you in the air no matter what:
(sidenote: it takes a lot of practice to be able to build jumps like that, almost as much as it takes practice to be able to ride them:)

Now, the optimium between height and length can probably mathematically be derived but I don't know how. I do know in the end it is irrelevant: once you practiced enough sometimes you'll just want to flow through lines without going particularily high while other times you'll try to really boost it. Another thing to realize is that pure distance at itself is almost never the aim: you'll rather want the perfect distance to nicely clear the jump. And not much further than that or you'll land too deep into the transition of the landing which makes it hard to maintain speed.

As for the actual answer (finally): as said I cannot explain it very well, but to go heigh (on jumps as pictured above) you basically push the bike against the transition, somewhere in the center so well before the lip, using mainly (at least for me) legs and arms. Doing that pushes the bike somewhat in more in front of you and forces it to follow the an upwards direction of the jump, and your body follows that. I don't think there is any pulling up on the handle bars until you are airborne. On the contrary, pushing the bike into the transition means extending limbs. This is a pretty good illustration you can also check the rest of the explanation there:

Final note: I rode/ride quite some dirt and met many people and when talking about it is usually in rather vague terms like 'push the bike' etc. It is just hard to break down all steps because they happen so fast and as a consequence it is hard to explain it to others. Best thing you can do is watch fellow riders or watch films, eventually in slow motion to see what exactly happens. But even if you do that you'll need practice, practice and then some more practice and one day you'll realize you suddenly know how to do it. If you can then explain exactly why, please report back here!


Mountain bike forks will normally direct mount to fit a 160mm rotor. The 180mm adapter you purchased will add 20mm to rotor size - so should (might) work with a 160mm rotor. You would need an adapter to increase 40mm rotor size ir you want to go to a 180mm rotor.

You could try a 203mm adapter or drop back to a 160mm rotor - either might work but I have not had experience with this setup.

Looking at the post mount, I would be a little concerned the mounts are up to the forces a 180 rotor could generate and would be checking the specs from the fork manufacturer.


Bicycle Computer Mount for Small Diameter Handlebars

Most computer mounts come with plastic spacers that can be placed between the hard plastic mount and the handlebar. If yours didn't come with that, I have used Athletic tape to build up the bars to the point where the mount will grip the bars adequately.


Compatibility for old Sram 7-speed shifter

Edit: Just checked an old copy of Sutherland's Handbook for Bicycle Mechanics (6th edition), and the SRT300i is actually Shimano-compatible, pulling 2:1 ratio. I've updated the comment below to correct that mistake.

Many SRAM shifters, are only compatible with SRAM "1:1 Actuation"* derailleurs. Shimano shifters and derailleurs use a "2:1" ratio of cable pull to actuation - the MRX you linked to at REI is one of the few SRAM models that are designed to be Shimano-compatible, like the SRT300i you have now.

(The SRAM ratio is actually closer to 1.1:1, while the Shimano ratio is about 1.7:1, but the common terminology rounds these values. The spacing between cogs in 7- and 8-speed systems is 5mm. In practice, this means that one click of a SRAM shifter pulls about 4.5mm of cable to move the shifter over 5mm, while each click of a Shimano-compatible shifter pulls only 2.9mm of cable to do the same.)


I've had many sets of painted rims.  All of them were painted by a professional whose day job was cars.  I have no idea what the prep and such involved was, but all of them looked great until I cracked the rims, had large rocks take chunks out, whichever.

Paint is certainly not going to hurt your metal rim, and it may offer it some protection.  Whether or not the paint stays on (which doesn't actually seem to be your question) is a matter involving far too many variables (prep, materials, care, conditions) to answer.  Unless you are planning to use some frightening type of paint I haven't heard of, you won't damage the rim by painting it.


Rack (& Pannier) for a bike with disc brakes

2019 Update

Racks specifically designed for bikes with Disc brakes have become much more common. It shouldn't be hard to find something now.

Original 2011 answer

I think the LBS is partially correct, that bikes with disc brakes aren't generally designed to hold a rack.  That said, I think there's a few solutions (other than getting a bike built to have disc brakes and a rack):

Get a seat-post (or similar) mounted rack.  Downsides: very low weight limit, often not good at holding panniers, and probably prone to spinning around.
Use "p-clamps" instead of the built-in holes.  These are rubber-covered clamps that would go around the seat stays to give you a hole for a rack up above the problematic disc brake stuff. This is more usually done on bikes that simply don't have a place to bolt anything on. Downsides: may put the rack too far up, may put the rack too far forward, may slide, may not be as strong.
Spacers and a longer bolt with a somewhat wide rack. So that the rack's stays run to the outside of the brake hardware.  It seems to me that too much weight would tend to try to bend the bolts down and the holes up.  Would be much better if you could find a rack that could use both holes.
I don't know the right term, but it might be possible to find a metal piece that screws into both of those holes and gives you a new hole behind that location.  I've seen some racks mounted like that to get the rack back further for more heel clearance.
There are racks made to go on bikes with disc brakes.  The one I found first ( http://www.topeak.com/products/Racks/ExplorerTubularRack_discMount ) basically has the spacer I suggest in #3 built in.  The second one I found ( http://www.tubus.com/en/rear-carriers/disco ) basically comes into the holes from behind instead of directly above, like I suggest in #4.

A rack specifically designed to mount on a bike with disc brakes would be best, of course.  The other options might be cheaper.


Cyclocross frame size vs. road bike frame size

Bicycle sizing may vary by bicycle type, region, manufacturer, and material. And measurements typically are of a length of the frame (usually bottom bracket to top tube: How do I measure the size of my bicycle frame?). So it would not be surprising if this statement was true.

Depending on the geometry of the frames, two bikes may have different "sizes" but actually fit the same size rider well. It is possible that cyclocross frames tend to have a smaller measured sized.

Here is a post that goes in depth... and is ultimately inconclusive: http://www.bikeforums.net/archive/index.php/t-138316.html


How to tell what length of chain to get?

If your old chain was 114 links (assuming it was the right size to begin with) then it's a good idea to take a couple of links out of it. It'll still work with two extra links but shifting may not be optimal and the chain will fall off more easily. Keep in mind that one chain link is composed of an inner and outer link, so a link is actually two pieces with a hinge in the center. This means that to remove two links, you'll actually remove four pieces of chain with three hinge points.

If the old chain was 116 links and you're trying to replace it with a 114 link chain, you'll run into problems. A chain that is too short can jam when shifting and puts puts too much strain on your rear derailleur.

To determine the correct length, wrap your chain around largest chain ring in the front and the largest rear sprocket, without running it through the derailleurs. Make sure that the chain is long enough for one full link (again, inner and outer) to overlap and you'll probably be spot on.

You can read more about it here: http://sheldonbrown.com/derailer-adjustment.html#chain


Cyclemeter is my favorite ride tracker.  If you are a bike commuter, you will appreciate seeing your splits and daily times.

Endomondo is also a nice app, and runs on a variety of other smartphones.  It's free, but more web-based, whereas cyclemeter is more phone-only.


How to fix a rim, that bent vertically inwards?

Vertical adjustment of a wheel is exactly the same as adjusting for wobble, except you loosen the nipples going to both sides of the hub rather than tightening one side and relaxing the other side.

Wheel truing is an art that can be explained but not learned without doing.

Most wheel truing stands have a way to measure "out of round" as well as left/right wiggle.

Depending on what happened to the rim, it may be stretched or dented in that spot, or it may require ridiculously spoke tensions to pull it back to "round"

You have to make the judgement call about how bad it is and whether replacement is required.


How should an unattached SunRace R90 bar end shifter behave?

Found this on Rivendale Bike works regarding the R90 barend 9sps:

  Use: They click but don’t index. Out of the package and not on a bike, they click about 18 times. In the span of shifting over a 9-sp cassette, they click about 13 times. This sounds trick or confusing, but it isn’t at all. Like a with a pure friction shifter, you move the lever til the shift is made. With these levers, the first three clicks coincide with the small three cogs. After that, it takes two clicks to get the subsequent cogs.
  Now, I totally understand if this weirds you out, but don’t run away so fast—nobody on Planet Earth has shifted these levers even 1/20th as much as I have, and I’m telling you, it is a cinch. In the mid and upper range, one click isn’t enough, but two clicks are.

Source: RIVBIKE.COM


What is the difference between a road bicycle tire size 700 x 23c and I 700 x 23

700x23 and 700x23C and 700C x 23 and 700x23c and 700x23c all mean the same size of tire.


For the same reason you can't have a fixie with a chain tensioner.

The load on the chain when slowing a fixie is too great and in the wrong direction for a derailler or tensioner to hold. The cage will be pulled forward and your chain will skip make a nasty noise and most likely come off or break something expensive.


What 70's/80's freewheel threading is most common in central or eastern Europe?

Suzue is a Japanese company. The threading for the freewheel is ISO for the Suzue Sat. No. 6.

In general, its quite easy to measure these things by just measuring the thread pitch. Aside from French and Metric BMX freewheels, the rest of the freewheel standards (English, USA, ISO, Italian) are all 24 TPI and about 1.375", and are effectively interchangable.


What is the cheapest way to send a bike from Australia to Germany?

Check with the airline you are flying with. Airlines generally have a small surcharge for taking a bike along, since people frequently travel with sporting equipment.

I looked into flying with a bike from Canada to France last year and it was only a $30 charge on the airline I was flying with (they even accepted tandems). I can't guarantee your airline will be as reasonable, but it's definitely worth looking into.


Is there anything special about rotor bolts?

The Torx heads are generally lower in profile than equivalent bolts with a hex socket. This solves clearance problems in some fork-wheel-disk setups.

Torx heads can be made shorter because the star pattern of the hole provides more contact points with a screwing tool, thus allowing reaching the same torque values without risk of stripping the bolt head. An equivalent sexagon head would have to be higher to reach the same torque value.


Can you take apart rear derailleurs, and how do you put them back together again?

In my experience the metal caps are mated to the wheels, and while the jockey wheels look the same they are not. Every time I have found the wheels not spinning it has been a simple case of having the wheels in the wrong position or being mated with the wrong bearing cover plates. If you have both wheels not spinning then I think you probably have bearing plates swapped; if one turns and one does not then you might have the plates on correctly but the wheels swapped causing the thicker wheel to be clamped tight while the thinner wheel is barely touching the cage.

I have never used loctite when reassembling bike parts, just care in assembly and a checkup tensioning after a couple of rides. In fact I often dab a little grease on threads to avoid rust binding.

It is probably worth buying jockey wheel replacements if you are servicing a 10-year-old derailleur. If it's a Shimano or something else relatively common chances are you can buy original replacements or even fancy anodised aftermarket parts.


Tim Paterek Manual for Bicycle Framebuilders contains the chapter on geometry. Very old version of this manual can also be downloaded for free.


Is it a problem to have tires of different width?

37mm / 1.4" vs 40mm / 1.6" is not a very big difference. There should be no problem for casual riding.

I'd keep the larger tire on the back as the rear wheel supports more rider weight.


Front wheel shifting left on braking with new front shock and fender install

First thing to do is check if the wheel is actually moving in the fork, or that the fork has slop or play in it.

Stand next to the bike, hold the bars, apply front brake and try to move the bars side-side and front-back. If you feel slop or play, don't ride it and take the bike straight back to the store that did the installation and have them fix it.

It may be that braking is causing the fork to bend slightly and move the wheel left. You could also take the bike to the store, show them the problem  and ask them to check their work.


What is the actual cable pull of brake levers?

A long pull lever (i.e. for V-brakes, mountain mechanical discs) pulls the cable about twice as long (but about half as hard) as a short pull lever (caliper, cantilever, road discs).

This is determined by the distance between where the cable ends and where the lever pivots. According to this thread, its significantly lower for short pull than for long pull with some variation (it seems like under 30 mm is a cutoff for short pull to long pull if you're picking a lever out of the bin). Park Tool states that the distance from cable end to lever pivot is around 21 mm for short pull (around 42 for long pull lever), and with a 20 degree movement (think the cable end to lever pivot distance as a radius of a circle - with this radius, and the angle at which the lever bottoms out, you can calculate the total possible cable pulled), you pull about 7 mm of cable for short pull (versus 15 mm for a long pull lever).

Obviously, there is some flexibility in this parameter, allowing different manufacturers to design different cable pulls to get different sorts of lever feels. This can also be adjusted on the fly with systems like Avid's Single Digit line of brake levers. Someone claims the adjustment on the Avid Single Digit levers is enough to run short pull (YMMV). Usually when you buy a brake (or lever) from Shimano or SRAM, the manual specifies an "optimal" lever (or brake) to pair with.

If you run long pull lever with short pull brakes, it will be easy to pull the brake, but very hard to apply braking force with a hard lever feel. If you run short pull lever with long pull brakes, you will likely bottom out the lever before stopping (or lock up the wheel) with a soft lever feel. So, make sure to match the pull of the lever with the brake for your safety (obey the manual, except at your own risk!).

You can switch between the systems with a travel agent. Some levers also have a switch which can work with both types with the flick of the switch (Shimano ST-EF65 shifters+brake levers, for example).


Does leaving a flat for months damage the wheel?

Leaving a flat for months won't damage the wheel assuming the flat is the only factor in the equation.
If the tire going flat was part of a chain of events there might be damage.
If the tire was sitting in a half inch of water, the tire went flat and the steel wheel was now sitting in water the rim might rust. Even in this example I doubt the rust would be bad enough that the wheel would be unusable.


Did I purchase the correct brakes for my Huffy bike?

Firstly you need to confirm the material of your wheel. If your wheels are carbon fiber, you need to use the professional brake pads made of cork which are normally labelled as "use for carbon rims".

If your wheels are aluiminium/alloy or steel, use pads made of rubber.

Secondly you need to confirm the brake type of your wheels. The mountings for V brake pads and caliper brake pads are different.

Your photo shows pads for an older bike with caliper brakes.

Please take a picture of your brake and add it to the question.


Burley Flex Connector, square tube vs round tube, does it really matter?

These trailer hitches are interchangeable and I have no issues.  I'm using the round connector in the square tube since it physically fits.  I have put some miles on it on it hauling kids bikes, pulling kids in sleds (recommended to keep the rope out of the tire and carry a spotter), and a 90 mile weekend camping trip.  I have had no issues with it.

As a bonus here I took a round connector out of another trailer that really has some miles and years on and put it on a new trailer (Trek branded Chariot).  The tongue was squared tubed and too small for the connector but I was able to take a stone grinding wheel to the connector and re-size and shape to get it to fit.  No issues found in it at all.


Modded folding bike and strange chain skipping on most gears

With reference to the new/used bits of your question, note that using worn consumables (chain, cassette etc.) on a bike is never a good idea, largely because you're in the dark as regards how much life is left in them. So my best guess is that the chain or maybe both chain and the cassette needs replacing for new parts.

Assuming that these parts are actually ok, then the problem becomes one of poor mechanics. Two things spring to mind:

(1) the chain you used as a replacement is the wrong length, and/or
(2) you did not adjust the derailleurs correctly after your chain/cassette changes.

And are you sure you have fitted things to this bike which are compatible with those you removed?


How to know what size bottom bracket to buy

More than likely it's a 68mm wide English threaded BB shell on the frame. You may just want to wait until you get the frame to verify that. The Tech Specs on page for the crankset actually do say that it's designed for "103mm bottom bracket" and "JIS Square Taper". Those should be all the measurements you need (assuming the frame is 68mm English): 68/103/JIS.

If you want a matching Sugino BB, here's one: https://www.ebay.com/b/Sugino-Square-Taper-JIS-Bicycle-Bottom-Brackets/177805/bn_5810397


How practical are clipless pedal shoes on a long bike tour?

They are nice to walk

Proper fitted MTB shoes with SPD cleats are quite comfortable to walk in, at least for non-marathon distances (say, less than 10 km a day). They are still less ideal when compared to normal walking/running shoes, however, for these reasons: 1. They are stiffer than regular shoes.
2. They have less gripping surface because the metal plates do not grip at all.
For really long tours (weeks) you will want to have an additional pair of comfortable camping shoes, crocs or "slippers" which you put on at the end of the day of cycling.

They are robust against weather

There are even MTB boots with SPD mounts, meant to be used while fatbiking in snow and well into freezing temperatures. You will have to strike a balance though: 100% waterproof things will be extremely hot in any other non-rainy day, and vice versa, breathing shoes will become wet in a thunderstorm.

The cleats on the shoe are robust (I'm going to be in areas without a proper bike shop)

Cleats are not coming with shoes, they are bought separately or with pedals. You can have a pair of spare cleats with you if you are concerned with their reliability. Do not forget to take spare cleat mounting bolts as well: it is more likely to lose a bolt than to break a cleat.

The pedals are robust too

SPD pedals are organized the same way as regular platform pedals, with a couple of extra springs and pieces. They are therefore as robust in their construction as the platform pedals. The locking mechanism can of course fail or become damaged. If you are concerned with such a possibility, pick a pair of SPD pedals with a small platform (compare e.g. Crankbrothers Candy and Eggbeaters; the latter are very minimal, the former ones have platforms), so that you can continue using them even if the spring fails. Alternatively, there are two-sided pedals that can be used as regular platform pedals on one side and as SPD pedal on the other. This way, you'll always be able to continue the journey.


Difference between Shimano HG and XT cassettes

XT is shimano's MTB line - and its second below the XTR line.  It weighs a claimed 275 grams, and can be split in the middle to remove a medium cog and add a larger one on the end.

HG is also a MTB line, but ranks somewhere below XT.  It weighs more at around 430 grams, and therefore is more solid.  It cannot be tweaked, but will be more robust and less prone to breaking.

In 2016, the Shimano MTB group lineup is something like this:

Lowest TOURNEY, ALTUS, Acera, ALIVIO, Deore, Deore LX, Deore XT, XTR Highest

By comparison, the road groups are

Lowest A050, Tourney, Claris, SORA, TIAGRA, 105, Ultegra, DURAACE, Highest

A further breakdown can be found at http://productinfo.shimano.com/#/lc/1.7

To clarify - here's shimano's current line up, according to shimano, from the link above, which is dated 2016 and titled "Product lineup"

Note this is from the PDF linked from that page.

Answer My advice would be to get the cheaper heavier cassette and a new chain at the same time.   They are wear items, and should be replaced periodically.  Some indication that the light one was perhaps too light for the amount of power some riders were generating.


What is the the difference between the new MTB Altus, Alvio, Acera?

In increasing quality (and expense) is Altus, Acera Alivio.

In real world conditions, there is not a lot of difference between each set. Experienced riders will probably notice that Alivio is better than Altus, but other factors such as shifters, cables and drive train wear make a larger difference

General advice I give to  people is buy the right component - i.e. that matches the number of speeds and cage length - that's on the largest discount but still in your budget.


Sand + Saltwater and unsealed bearings are not a good mix.
Some things to consider depending on the value of your bike and cost for replacement parts are:

Upgrading your bottom bracket to a sealed bearing. Sure there is some frictional loss there but even road cyclist use it on training bikes for bad weather riding

Upgrade wheel bearings to sealed bearings/rebuild them more frequently

I assume your bike is either aluminum or carbon not steel. If it is steel washing it to prevent corrosion from salt would be a must and touching up paint chips to protect the steel is a must too.

Clean braking surfaces after each ride whether rim or disc brakes to avoid sand wearing them out prematurely.

Use a proper lube on the chain and clean your chain frequently. I personally would use a wet lube, but if you consistently find yourself in powder sand, then perhaps a dry lube would work and avoid having sand stick to it. However, I have found that dry lubes tend to lose their functionality even after 1 splash from a puddle so chose carefully there. Some suggested lubes that I have used (WD40 Wet Bike Lube and Finish Line Ceramic). I find 100 - 200 mile chain cleans work well for me on road conditions. If I rode on the beach and had a lot of sand stuck to the chain, I might service the chain more often like after each long ride, etc. Here is a link to a typical chain clean service -


How do I compare seemingly equal wheelsets?

The Hed wheels may be slightly better in an objective sense, but the absolute difference may be small. Additionally, as a consumer, it may be hard to tell where they're better, and by how much, just from the specs. As outlined below, a lot of differences may appear in areas that consumers can't see on their own.
You might get a general sense of quality by asking around on internet forums or in bike stores, but these responses will inevitably be prone to the responder's own confirmation bias, placebo effects, and other subjective issues. I recall a podcast (Marginal Gains) where the author (Josh Poertner, who's worked at Zipp wheels before) relayed a story: he was working with the US Postal Service team, and the riders complained that his carbon wheels were too flexy (that is, they flexed side to side when ridden hard). Josh had tested the wheels' lateral stiffness, and they objectively measured up to competitor wheels. He got in touch with an aluminum anodizing company, and asked them to anodize a batch of the hubs for the wheels in a very bright red. He swapped out the hubs ... and lo and behold, everyone said the wheels were now very stiff and fast. Most responses on the internet will be plagued by issues like this, and the fact is that the Hed wheels could be prone to this because they have a very nice finish (see below). This response tries to outline objective factors that might differ from rim to rim in general.
I’m not able to see a price attached to the Specialized wheels, and I suspect they’re OEM wheels (I.e. they come stock on a lot of Specialized bikes, and aren’t usually sold aftermarket). I suspect that a $250 price might just be for a front wheel, but I could be wrong. Either way, the Hed premium may or may not be worth it.
Tolerances - rim, hubs, and build quality
All components have some manufacturing tolerance. For example, a manufacturer's site might say that X rim weighs 450g. In reality, that means the mean weight is 450g, with some standard deviation or variance around the mean. Good rims will vary less. Poor quality rims will vary more. The rims can be more or less round. Relevant to tubeless tires, their internal diameter may be on the high side of the industry-specified tolerance, or it may be right on the tolerance. (Side note: aluminum rims are extruded from a die, but the die wears as time goes by. Hence, a rim's mean weight actually creeps up over time. All manufacturers are likely tempted to understate their mean weight, but perhaps the poorer ones might have a greater incentive to do this.)
I have not patronized November Bicycles, which builds custom wheels, but I trust their analysis. They have spoken very highly of the tolerances and overall quality of Hed rims in general. Here’s their review of the Eroicas.
In contrast, the Specialized wheels are likely to have a rim from a generic Taiwanese manufacturer, e.g. Kinlin or Alex. By itself, this is not a detriment. In fact, if you go through November’s blog, you’ll see they’ve spoken favorably of many Kinlin rims, and they’ve offered some in wheel builds. Many companies selling wheels are in fact using some combination of Taiwanese rims and hubs. In fact, I've had wheels with Kinlin rims and generic Taiwanese hubs before, and I've been quite satisfied. The potential issue with the Specialized wheels is that we don’t know what rims and what hubs. Their rims might be lower quality and higher variance in various tolerances than the Heds. In practice, this might mean that if you buy a pair of Specialized wheels, the probability that the rim wasn’t as round as it should be is higher than on the Heds - albeit the chance of an issue should still be low, and we consumers can't estimate that chance reliably. The same issue with manufacturing tolerances applies to hubs.
The issue with tolerances also applies to the build quality - that is, how true and round (I.e. lateral and vertical tolerance after building) the finished wheels are, and how even the spoke tension is. This affects the wheel’s lifespan. Most mass-produced wheels are machine laced, and finished by hand, and the build quality varies. The issue is, there’s no reliable way for us to estimate that tolerance for Hed and Specialized wheels. I note that you said the Hed wheels are built by hand. In principle, I think that a skilled wheel builder can achieve better results than the usual mass production technique, but I don’t necessarily know that what the average skill level is at Hed, and I can’t confirm from their site that all wheels are built by hand.
Some other places to look for differences between wheels are as follows.
Spokes
Type
The Specialized site says that they use DT Competitions, which are 14/15 gauge, or 2.0mm/1.8mm butted spokes. The Hed site isn’t informative, but they said round steel spokes, and they’re very likely to be similar to the Competitions. It’s possible that Hed used a super light butted spoke (e.g. DT Revolution or Sapim Laser, both 14/17g, where 17g is 1.4mm), but they would have said. Many wheels at the Hed price point use a bladed spoke, which results in a small aerodynamic advantage (November bicycles calculated the advantage at 11 grams of drag at 30mph, which is about 1 watt; comparison was a 38mm carbon rim with 20 Sapim CX-rays, which are 14/17g bladed spokes, vs the same rim, 20 Sapim Lasers, 14/17g double butted round). Wheels at lower price points may use straight gauge spokes (e.g. 14 gauge, or 2mm, through their whole length). These are heavier, and possibly less durable, than butted spokes.
Count
The Specialized wheels are 24 spokes front and rear, and the Heds appear to be equal. Heavier riders may want 28 spokes on the rear, or both front and rear. Fewer spokes are lighter and more aerodynamic, but the differences should be small.
Other spoke and related characteristics
Related to the spokes, many wheels use alloy nipples. These are a minor savings over brass nipples. Alloy nipples have a slightly higher chance of corroding and breaking, particularly if ridden in poor weather. It's also possible to round out an alloy nipple when truing the wheel. With the best quality alloy nipples, I believe that these issues are minimal. An issue might present if you're on a wheel that uses poorer quality alloy nipples. Otherwise, brass is a durable choice, and will penalize you by a mere 20g per wheel (or less).
Rim characteristics
Internal width
Another point of differentiation you need to pay attention to is the rim internal width. The Eroica is designed for big tubeless tires. I have no personal experience yet, but I think you would need at least a 28mm tire on that rim, and the Eroica is really a gravel rim. The Specialized rim is more typical in width, and can support road or gravel tires. Also see what November wrote about the Eroica’s bead lip, which is designed to improve tubeless tire retention.
Side note: for someone buying aerodynamic carbon wheels, you want to make sure that your tire width is a bit less than the rim's external width. If you want to run relatively wide tires (e.g. 25mm or 28mm nominal width, which may stretch to 28-30mm when mounted and inflated on a 23mm+ internal width rim), then you will incur an aerodynamic penalty if you exceed the rim's width. The average user might quite fairly ask, what do I care? However, if you've gone and bought an aerodynamic carbon wheelset, then you do want to at least consider this - you've gone and offset some of the aerodynamic benefit you just bought, so you may not want to do this unless you've got a good reason (e.g. the race course has some gravel sectors that are better handled on 28mm tires).
Depth
In general, rim depth may be a point of differentiation. Both these wheels are roughly equal in depth. In general, alloy rims tend to go up to about 30mm deep. Generally, the deeper rim, the more aerodynamic the wheel is. However, between 20 and 30mm deep, I believe the aerodynamic differences are small.
Construction
Cheaper rims may use a cheaper means of construction, e.g. a sleeved joint on many entry-level wheels versus a welded joint on more premium wheels, maybe even a pinned joint on a really cheap wheel. There's some discussion on rim joining methods here. NB that it's possible to produce high-quality pinned wheels. Cheaper rims may not be as smooth at the rim joint, so if those are rim brake wheels, the rider might feel a pulsing sensation each time the brakes pass the joint. Altenatively, cheaper rims might have the sidewalls more poorly machined, so rim braking doesn't feel as smooth. Obviously, this doesn't apply to disc brake wheels like the ones in the original post.
Last, more expensive wheels may use better alloys. I recall that aluminum alloys with niobium were slightly lighter and stronger than some other alloys - although, in 2017, niobium alloys were used by only one Taiwanese manufacturer, Kinlin. There are likely some points of differentiation between other aluminum alloys. However, I'm not familiar with metallurgy, so I can't provide further detail. In principle, if we were talking carbon wheels, similar differences would exist between both the carbon fibers and the resins used. Again, I'm not familiar enough with carbon wheel construction to give an opinion here.
Tubeless issues
Both rims in the original post are certified for tubeless use. However, at the time of writing, tubeless industry standards are still evolving. Not all tires may play perfectly with all rims. Reading November's blog, Hed's other rims seem to have good general compatibility. It's possible that other rim brands will not play as nicely with some tubeless tires, or even that one brand might make a few rim models that don't play as well. If the wheel's manufacturing tolerances are loose, especially around rim diameter and the diameter of the center channel in the rim, it's possible that some rims of a particular model will be on the loose side of the tubeless specifications, and they won't seat tires properly.
If this happens, you could be more vulnerable to burping your tires unexpectedly - this is where one of the beads comes loose from the rim temporarily, and you lose pressure and sealant. This is not good on gravel. If you are running road tubeless, this is really bad. Road tubeless is run at high pressure, so you will lose air much faster than on a gravel tire. This can cause people to crash. At speed.
Again, this is something that's hard for consumers to know and to measure. At best, you could ask mechanics if they've had problems with a wheel or rim brand or model. One possible issue with asking about that Specialized wheelset is that in the US, many shops will mainly sell Specialized bikes, and thus they may have an incentive to play down problems with the brand. Or mechanics may simply not have had enough experience with that wheel to give you a good answer.
Finish
Last, the finish of the rims is one area of differentiation. Rims might be done with a more polished or a matte finish, but either way, the good finishes should have consistent color across the rim and from rim to rim, as well as more durable clear coating. Additionally, good finishes will just look better. November has said previously that Hed wheels tend to have very nice finishes, and that the prices for the rims and wheels reflect that! In a purely objective sense, there is no point paying a premium for finish. November has commented elsewhere that there are rims that are high quality in other aspects and that are cheaper than Heds. But not everyone makes decisions purely on objective factors, and you are not obliged to do so either.
Hubs
Some name-brand hubs are known to be high quality (e.g. White Industries, Chris King, DT Swiss, Industry9). Some of these are quite expensive, but some are relatively good value for money (e.g. DT Swiss 350 or 370, although NB these versions are made in Taiwan whereas the 240 is made in Switzerland; a number of OEM wheels use DT Swiss 350 or 370 hubs, and I suspect these tend to be good value for money). Some premium hubs are also available in pretty anodized colors, but I won't focus on that because it's a purely subjective consideration.
I can't confirm, but I suspect that both the Specialized and Hed wheels have generic Taiwanese hubs, as I alluded to above. Many Taiwanese hubs are decent, but some are lower quality. It's impossible to tell which is which just from sitting here. Better quality hubs will tend to have better tolerances in their bearing bores, and better quality bearings. They may also have wider spacing between the wheel bearings. These should lead to longer bearing life. Additionally, bearing spacing, and other geometrical aspects of the hub (e.g. spacing between flanges) may affect the stiffness of the wheel. Remember that many generic Taiwanese brands are fine; in particular, I've heard that hubs made by Novatec and Bitex are good, as are the DT Swiss hub models made in Taiwan.
Elsewhere on this site, I've suggested avoiding hubs with particularly small bearings (especially 688 bearings for front hubs), as these aren't big enough to bear the sort of loads you take on bicycles, and will quickly wear out. That doesn't appear to be an issue with the wheels in the original post.
On the other end of the price range, one might encounter hubs with ceramic bearings. Good ceramic bearings may have lower rolling resistance than steel, and ceramic bearings are frequently used in industrial applications. Many bicycle ceramic bearings also have relatively low-contact seals, so these might be vulnerable to contamination. They'll need more regular maintenance than you might otherwise do to your hubs. In addition, they may need or may benefit from special low-friction grease. Objectively, the price per watt gained here is very high, and many of us won't notice the gains here. That said, I suspect ceramic bearings are more sensible in hubs than in the bottom bracket (hubs rotate faster than your cranks).
Degrees of engagement
The Hed hubs have 3 pawls, and the Specialized hubs have 4. Chances are that you will have to turn your cranks a smaller radius before your free hub engages with the Specialized wheels. That is, the Specialized hub may have more points of engagement than the Hed.
I would not care about this unless you are riding very technical gravel. Cyclingtips has a good discussion of points of engagement here. It does objectively matter for mountain bikers. They frequently have to stop pedaling, reposition their feet, and then pedal, perhaps while on a very steep hill. In that scenario, you obviously want your freehub to engage immediately.
Roadies will not objectively benefit from this. In fact, more points of engagement may mean more drag while coasting. Many gravel riders will not benefit either, unless they're on very technical terrain. There are some gravel bikes that have geometry similar to mountain bikes and that can handle terrain approaching what MTBs can handle. The OP's wheel choice and comments suggest that he's using these wheels on a gravel bike, so this might be something to consider.
The Gestalt
Overall, wheels will vary in their claimed weight. Lighter rims, hubs, spokes, and nipples will all reduce the wheel's overall weight. Some words of caution apply, however.

Small reductions in weight will only minimally reduce your time on a
given climb.
Furthermore, manufacturers often under-state the claimed weight on a wheel. It could be that the smaller, less well-known manufacturers have more of an incentive to under-state their weights. After all, weight is easily measurable, and 100 grams sounds like a lot of weight. It is not; see the first point. You will naturally be able to feel a 100g difference between two sets of wheels when you lift them with your hands, but almost all of us are not pedaling our bikes with our hands.
It's possible to sacrifice durability if you go too lightweight on some components. For example, a manufacturer might build their hubs with small bearings that aren't sufficient to take the load. They might use an axle that is too light and gets bent in regular use. Rims that are too light can be prone to cracking.

Wheels will also vary in their lateral stiffness. In the worst case, it's possible to actually (i.e. not a placebo effect as discussed in the introduction) flex a wheel side to side when you pedal hard, such that you rub the rim on the brake pads. Stiffness is a complex phenomena affected by the rim, the geometry of the hub, and the gauge and number of the spokes.


How to read the traffic light at this German intersection?

You're meant to cross the crossing in two steps (you'll need two traffic light cycles to turn left, not like cars who manage in one cycle).

I took the road names from here, which is, I think, the crossing you were photographing.

Starting from Jahnstraße, you go straight (on the right of the lane) along with the cars coming from Jahnstraße. Arrive at the holding line I marked in red . (And see all the cars with the same destination as you, cruise off over the river while you wait). Now you're standing in front of the cars going along Berliner Straße facing south.

For the second step, the small traffic light you highlighted is relevant (and the way these crossings are meant to be used, from this position it should be visible, but they are commonly misadjusted, don't know why, but it seems they see less maintenance). It's purpose is to give you a small head start ahead of the traffic queueing up behind you in Berliner Straße. This is why it's so short green, it's only for the few people getting packed in this short term "parking spot", it is not meant to be caught by flowing traffic. In addition to the headstart, it's meant to tell you when Berliner Straße has green - there's no way you can see the main signal.

EDIT: as top view (image from google maps)

you arrive on the black line
wait until the green traffic light turns green
continue on the green line
wait until the red traffic light turns green
continue on the red line

EDIT: for the benefit of those who want to take another look at the concept: similar bike-left-turn solutions exist in other towns, here in geneva, with streetview

with two of these small wait-spaces to wait for green on the next leg:

EDIT (adding some points raised in the comments):

This way of turning left is typically a safe and easy way to turn left on crowded crossings, even if you're not very familiar with roads. The biggest danger is cars turning right and running over you when you go straight on the first leg - that's the same as when you go straight and unfortunately omnipresent in Germany, not only on crossings like these. If you're confident to do it, you can probably also turn left on the car lane - it might be a bit of a hazzle to reach that lane, I'm not sure how legally evil that is, but it's probably not too problematic if you know the crossing. I cannot judge how much of an obstacle you'll become for cars turning left - I think it's two lanes turning left in parallel.

In my experience you're meant to do the 90° turn before coming to a stop in Germany, and after the stop in Switzerland; such that in your case you just accelerate straight once the second traffic light turns green, that's the position for which the traffic light should be adjust.

PS: on the top view you can also see similar waiting places for coming from the south on Berliner Straße and turning left into Im Neuenheimer Feld; and with lane marking, the way to go from the north into Jahnstraße to the east.


will Shimano Shimano Dura Ace 7700 STI Flight Deck work with Rear Derailleur Shimano XT RD-M771

Yes, all nominally 9-speed Shimano mountain RDs will work with ST-7700, and all pre-11-speed road FDs will work with ST-7703, except for FD-4700 at present and any future 10-or-fewer groups that use the 11-speed actuation ratio.


The compression ring is a wedge.  There will always be space and movement here, until the headset is assembled and adjusted.

It looks like you're missing a part. There should be another hoop with a wedge shape and a split. It's the split ring on the upper left in the image below. This part is what grips the steerer tube tight and will eliminate the clonking you're experiencing.

If you are confident that all the parts are there, and assembled in the correct order, then you have 3 likely reasons for movement:

The first is that there is damage to the bearing cartridges.  This can show as movement when adjusted correctly, although usually on a headset it will fail first by being rough or crunchy feeling.
Secondly, there may be movement between the frame and the headset cup, which can mean that the frame is in need of replacement.  This can't be fixed via adjustment.  There are ways to attempt a fix, but it is best looked at by a qualified mechanic, first.
Last, there may be no movement in the headset, but you could be feeling movement in the brakes, depending on how you are checking for movement.  Try checking for movement by standing the bike on the rear wheel, turning the handlebar all the way to the left or right, and checking for movement with your hand around the headset.  That way if it is in the headset, you will feel it directly.

I hope that is helpful.


stiff gears and chain coming off while pedalling forward (hub gear)

There could be a few different issues:

It your Rear wheel is sliding around in the rear dropouts and you wind up loosing tension on the chain or screwing up the alignment of the rear wheel. It's really a common thing on bikes with horizontal dropouts, which I assume your bike has.  When you start to pedal, if the rear wheel bolts or quick releases are not tight, then the wheel can slide forward in the dropout, the chain comes loose and falls off. Try tightening bolts or quick release tighter or use a chain tensioner or tugnut to help prevent the axle from slipping.
Your chain is really worn and/or your cogs are very worn, this causes the chain to skip off the front chainring or rear cog. See Sheldon Brown's site about chain wear to diagnose this issue.
You have a bad chainline.  Instead of going from the rear cog on the wheel to the front chainring in a straight line, it bends the chain diagonally, causing it to hop off the cog or chainring easily.  This may be due to spacers incorrectly placed on either side of the rear axle. Credit @DanielRHicks
The chain could just have too much slack, try pulling the wheel back and resetting the tension tighter.
Bent chainring causes chain to jump.  Spin the chainring without the chain and see if it 'wobbles', if so this could be causing your chain jumps and the chainring should be replaced.


Old chain still shifting perfectly, should I change it out?

You didn't mention what gauge you used, but there are many kinds. Take a look at that link; it is worth reading, as is this thread.

The current smoothness of the shifting isn't usually the deciding factor regarding when to change, but rather the cost of the other components that wear faster when the chain is worn: the cassette, and the front chainwheels. The idea is to replace the chain (relatively cheap in comparison) before it starts to damage the more expensive cassette and front chainwheels.

In my experience I get about 2,000-2,500 miles out of a CN-6701, and I'm riding in near-ideal conditions (Southern California weather). I'm pretty careful about keeping my chain clean and properly lubed. I typically replace the cassette about every three chains, and the front chainwheels (Ultegra as well) are still OK.


Spinning bike speed vs outdoor ride speed

Based (very roughly) on this calculator here, I'll guess 28 km/h or less.

Using a 0 weight rider and bike with no wind and 200 watt output you get roughly the speed you are getting on the trainer (the weights are used for rolling resistance).  Leaving the power the same and changing to 80kgs, a 9kg bike and 15 km/h wind it gives 28 km/h which is a significant drop.  I am not sure about all the formulas the calculator is using, but introducing rolling resistance and wind resistance will surely take big chunks out of that speed.

I am not sure what kind of spin cycle you are using, but depending, it may be introducing some sort of resistance that it equates to rolling/wind/mechanical resistances.  However, it's likely much less than what you would encounter out on the road.


What are the Pros/Cons of a 2.1 vs 2.3 wide Mountain Bike Tire

From Tom J. Stokes excellent article on choosing tires:

Wider tires tend to grip better during cornering and over rough terrain, at the expense of increased rolling resistance and weight. Wider tires will also float better in sandy conditions and are much more resistant to pinch flats when riding over sharp rocks or off of drops. For moderately rocky cross-country use, the sweet spot is between 2.0″ and 2.3″. If you primarily ride smooth hardpack or travel at a leisurely pace, choose a 2.0″ or even a 1.8″ tire. Likewise, if you tend to corner hard on the downhill and ride rough terrain, lean toward a 2.3″ tire. For downhill mountain biking where pedaling efficiency is less of an issue, look for a tire between 2.3″ and 2.6″. Tires up to 3.0″ wide are available, but rolling resistance becomes very significant past 2.6″.
The front tire is typically subjected to more cornering forces than the rear tire. Likewise, the rear tire is usually loaded with more weight while pedaling. Consider using a wider tire in the front with a slightly narrower tire in the back to get the cornering benefits of a wider tire with the rolling resistance advantages of a narrower tire in the rear. I’ve had good luck with a 2.5″ tire up front with a 2.3″ tire in the rear on my downhill bike.
Also note that widths are approximate. I’ve got a 2.3″ tire which measures 2.5″ wide with my calipers, and a 2.4″ tire which is actually only 2.25″ wide. Make sure that your frame and fork have enough clearance to support the width of the tire. Maximum tire sizes are listed in the owner’s manual. If you ride through mud often, allow for even more tire clearance to keep mud from building up between the tire and frame.

Honestly though, the difference between a 2.1 and 2.3 is very small - I would just get the highest quality tire you can afford that is between those measurements.


Am I correct in thinking (based on your PinkBike comment) that you've never personally participated in a DH race?  I would very highly recommend you compete in a few before trying to put on one of your own.

There's a ton of things you'll need to think about, and the best way to get a good list is by attending one yourself and looking around with a critical eye.  Off the top of my head, other things you need to prepare

Bathrooms/porta potties
Race bibs
Food/water
Course marshals
Parking
Prizes

Other suggestions from comments
Insurance - @Daniel R Hicks
Medical support - @Jahaziel
Course preparation @Jahaziel
Race Categories - @Jahaziel

Competing in a race would give you a chance to look at all these things, and how they can be done well/poorly.  It would also give you a chance to speak to the race organizers in person (although they'll likely be quite busy, you may need to wait until the end) and pick their brains.

If going to a different race isn't an option, you might still try to contact organizers and talk to them over the phone.

In response to your specific questions, I know there are websites to handle registration; you might check out http://racesonline.com/, they've done a few races I've been to.  Or you could probably get all the info you need with a Google Drive Form, but that might be a little hard.  On the upshot, it would be free.

As far as timing, there are companies that will rent/come out and operate chip timing equipment (I don't know any off the top of my head), but the budget way to do it is to start two stop watches at exactly the same time in the morning before the race, then send one to the start and one to the finish.  Then you have a person at the top recording the starting time of each bib number, and a person at the bottom recording finishing time.  At the end of the day you go through and subtract all the start times from the finish times, and presto!  This is very cheap, but it's imprecise, and it means you don't get results until the end (unless you have more people with radios communicating times back and forth, which is doable but requires extra hands).

Practice runs seem like they're more or less up to you, and could probably be handled with a chalk board.


Inner tube size and can you feel the slime in inner tubes?

I see this as a two part question.

A 1.5- 2.125 width tube will fit in a 2.4" tyre fine.

I carry 2" wide tubes in my seat pack when I go cycling as a spare tube for my 2.35 tyres. I do so purely as it fits nicer in my pack and my tyres are tubeless. So if I get a puncture, I put the tube in and fix the tubeless when I get home.

You won't notice the weight but Slime might not work as well with over streched inner tubes.

When you fit a slimmer inner tube in a wider tyre, it streches more. So if you get a puncture with a slimmer inner tube, the slime has to work harder (than with a correct size tube) to plug the hole as it is more likely to burst bigger due to the over streching.

Personally I would rather invest in a more puncture proof tyre than in using Slime.


My MTB tires say "Inflate to 50 PSI". Can I inflate them a little more for commuting?

How wide are the tires compared to the rim? Wide tires at high pressure put stress on the rim’s sidewalls which can result in sudden, catastrophic failure. If the tires are relatively narrow it’s probably okay to over-inflate, but I doubt you’ll see much benefit. There are diminishing returns for rolling resistance.

See for example this test of 56mm wide Vittoria AKA tires https://www.bicyclerollingresistance.com/mtb-reviews/vittoria-aka-2015 which have a very high rolling resistance to begin with:

Rolling Resistance Test Results (Speed: 29 kmh / 18 mph / 8 m/s, Load: 42.5 kg / 417 N)
Inner Tube  Conti MTB 29 (225 gr butyl)
Rolling Resistance 55 psi / 3,8 Bar     35.6Watts
CRR: 0.01067
Rolling Resistance 45 psi / 3,1 Bar     36.3 Watts
CRR: 0.01088
Rolling Resistance 35 psi / 2,4 Bar     38.0 Watts
CRR: 0.01139
Rolling Resistance 25 psi / 1,7 Bar     40.7 Watts
CRR: 0.01220

As you can see, the effects of pressure on rolling resistance are surprisingly small (though I guess for a tire of this width 1.7 bar is already a relatively high pressure). Going from 45 psi to 55 psi for this tire saved only 0.7W per wheel when measured at a relatively high speed of 29km/h. At the same time you’d start to feel every tiny bump in the road and you’d have decreased grip on pebbles or debris.

I dimly recall an experiment where high pressures even started to increase rolling resistance on rough surfaces above a certain point.

As others have said in the comments, getting some good, slick (i.e. treadless) tires will improve rolling resistance much more.


The details depend, but as a guide expect to install pedals and wheels and attach the handle bar to the stem (2 or 4 Hex bolts). Unless you are DIY challenged, the most time consuming part will be removing the packaging material from frame, handlebars, wheels.

The disc brakes will (should) have packers that will needed removing. There might be plastic spacers in the forks and "plugs" to remove from the cranks where the pedals go in.

Once assembled you need to tune the gears and check the brakes are working an aligned correctly. Check all the bolts and nuts are tight (use a torque wrench if you have one, else be careful - tight as in firm, not tight as in done up by a 600 pound gorilla holding a spanner)

If you have any doubts, your LBS will be able to assemble it for a about 1/2 hour labor charge.


That chainring doesn't look particularly worn from this angle. The wear would make the teeth look less symmetrical and more like shark fins. That shorter tooth allows the chain to leave that ring more easily when you change gear.

Ensure the chain is not worn out using a gauge (see http://www.bikeradar.com/road/gear/article/bicycle-chain-wear-explained-46015/ for what types of gauge are available and how to use them). If you grab the chain at the front of the chainring and pull it away from the crank spindle, you shouldn't be able to get more than about 1mm of gap between the chain and the dips between the teeth.


I'm not sure you know what tubular tires are (they are relatively rare), but I'll describe the 3 basic tire systems for bicycles:

The most common is the good old clincher tire.

(Image from Wikipedia: Bicycle Tire)

The tire (4=bead,6=casing,7=tread) hooks into the rim (1) via the bead (4). The air is held through an inner tube (5) which is protected from the spoke nipples by a rim strip (2).

Theres a lot of reasons for using this:

If you have a flat, you can easily swap the tube and/or tire, no mess required.
Tubes are repairable. Tires sometimes repairable.
Everyone knows how to deal with them and stocks them.
The rim doesn't have to be anything special.
Cheap, cause everyone's been using them forever.

However, there are some disadvantages:

Tubes do have some weight to them.
At low pressures, you can pinch the tube and get a flat.

A tubular tire is basically a tube wrapped in the casing and then glued onto the rim. A picture is given below:

(From this question)

According to Sheldon Brown:

Lighter tires and rims than similar clinchers
Less likely to pinch flat
But on the other hand,
Hard to repair
Expensive
Can roll off the rim if you don't glue them properly
Higher rolling resistance
Not always as round/true as a clincher.
Rare -- pretty much only certain racers use them (road, cyclocross).

Finally, we come to tubeless. The mounting system is the same as whats given for the clincher tire, except you don't have an inner tube (5) or rim tape necessarily (2) [Depending on the rim, you may need some tape to make it airtight]. We can distinguish between tubeless rims+tires and tubeless-ready rims+tires (the latter requiring using a liquid sealant with the tire+rim in order to seal the tire, while the former it is optional).

The good things are:

You can run lower pressures since theres no tube to flat (better traction)
Lower rolling resistance
The sealant provides some puncture protection for sealing

The bad is:

Installing the tire is a lot longer than a tubed tire (Schwalbe notes that it may take up to 3 days for the sealant to seal the tire)
Messier to replace a tire since you have to clean out the sealant
You may need to carry around a spare tube anyway, if something happens to stick in the tire and keep moving.

One may argue that tubeless are lighter or heavier than clinchers, but that depends on the system of tubeless tire, so I've left that out.

These things are primarily advantageous for mountain bikers. For road bikers, not so much.

The big reason why I think a lot of people still ride clincher tires is cause they're easy to maintain, cheap, and everybody knows how to deal with them and has the parts. Mountain bikers see real advantages with tubeless, while road bikers don't really see advantages, so they do ride tubeless fairly often, but still, the tube is not leaving us any time soon.


Is it worth it to get a bike computer with cadence?

I also think the answer is "it depends", but for slightly different reasons to Daniel. I think it depends on why you're cycling.

If you are training, then measuring cadence can definitely be useful. In fact, there are training programmes that are based around cadence. (You're basically looking for a high value, and a steady value.)

Otherwise, the information has more-or-less interest value only, although you could still argue that the "steady" side of the value could be used just to improve your technique.

As regards accuracy, cadence is measured using a magnet, just like speed and distance. So there's no reason why cadence should be any less accurate than speed and distance. It depends on the hardware of course but I'd expect computers these days to be pretty accurate.

As regards your reservations regarding wireless technology, again its going to depend on hardware but wireless is the way all the high-end computers have gone, so there is certainly not any inherent problem with this technology. It is possible to measure things like speed, cadence, power and heart rate, even I believe gearing info, all simultaneously, all wirelessly and without interference.


Good fit vs. Best fit - Lower end of the fit range (Difference of 1 cm). Is it OK? or can this tiny difference still cause pains?

The sizing chats provided by manufacturers are only really a guide. One should never pick a size based on them alone.

The only way to select a correctly sized frame is to test ride bikes of different frame sizes. As mentioned in comments, body proportions make a big difference.

Don't approach a possibly too-large discounted bike with the mindset of 'can I make this work?' Get the bike that is right in the first place. There will be other deals that come along. Also, remember that with a used bike you'll be doing maintenance and replacing wear items such as the chain and cassette sooner than with a new one.


How much air loss over time is considered normal / acceptable for a hybrid tire?

Tyres will always lose pressure over time, I would say that for cycle tyres 1-2 psi is closer to the norm for most including me. This is mainly due to the microscopic pores in the tyre/tube which air molecules escape through over time.

However don't forget that the air in tyres also expands and contracts with temperature, so on colder days tyre pressures will decrease slightly, and vice-versa on warmer days pressures will increase, it is considered that roughly 1-2 psi with every 10 degree increase/decrease in temperature is the norm here.

Natural deflation also occurs more rapidly the higher the pressure so as you reach a tyres max pressure it will deflate quicker, and thus to keep your tyres at max pressure you'll need to inflate them every couple of days due to the higher pressure loss rate.


Can I use a 27.5 fork on a original 29er (2015 Cannondale Tramount 3)?

The key to swapping forks is the axle to crown measurement - the distance from the center of the front axle to the seat of the crown race that is the lowest part of the headset. You want the replacement to be as close to the original as possible, to preserve the designed geometry. There are forks that can take either a 27.5 or a 29er wheel.
The suspension fork is heavy, if your goal is light weight then you should consider the correct length carbon rigid fork. You will need to balance weight, cost...and what is available. Remember that you need to find a fork with the same steerer diameter - you can't put a tapered fork on a bike built to accept a standard 1 1/8" steerer.
The difference between a 27.5 and a 29 can be large or small, depending on the tire size you choose - if you put a 27.5 wheel on the front with a 27.5 plus tire (3 inches wide) then the out diameter is nearly the same as a regular 29er tire, with a rigid fork you would have some suspension, too, without the weight.
Good luck!


Minimum chainring gap for front derailleur

If you look at the design of a Shimano FD, you will find a channel in the middle
https://www.renehersecycles.com/trouble-with-sti-triples/
Your FD will be similar to this one

If you review the Shimano triple FD specification, then you will find "Applicable Top-Mid tooth difference ", which for MTB type (FC-M) is typically 10t, and for trekking type (FC-T) typically 12t.
In your case you have 28-38-44t, which is a 6t gap.
This will not work well because the channel is positioned for a middle ring 12t smaller than the upper ring.
In the case of FC-T4010, there are two offerings - 48-36-26, or 44-32-22. A derailleur such as FD-T4000 which you might have fitted, is specced to work perfectly with both - they are essentially the same thing, just 4t further down.
A 6t gap is not in spec at all. Here it seems like you might do well switching to 48-36-26, but that would mean three new chainrings.
https://si.shimano.com/api/publish/storage/pdf/en/ev/FC-T4010/EV-FC-T4010-3661.pdf
Note that the chainrings are sold in sets, in that the 36t chainring is designed with ramps & pins which will pick up from a 26t ring.
In the past Shimano made 8-speed 48-38-28 chainsets such as FC-M361, which you could also use, or switch the chainrings from those onto your bike. But you won't get 44-38 to work well.
Note also that if you have an 8-speed drivetrain and a 9-speed chainset (which T4010 is) then the 9-speed chain is narrower, and the FD cage would be narrower  also. So depending on the FD that you have (8 or 9 speed), you would want to use:

9-speed FD with 9-speed chainrings and 9-speed chain and 8-speed cassette (RDs have no 'speeds')
8-speed FD with 8-speed chainrings and 9 or 8-speed chain and 8-speed cassette

It's not clear which chainrings you have purchased, but if you purchase a 48t chainring for a FC-M361 chainset, then it will pickup well from a 38t chainring, however these are 8-speed chainrings which are possibly not ideal if you otherwise have 9-speed chainrings fitted. However you'd want to replace the FD for a suitable '10t top-mid' type, such as FD-M313 (which is 8-speed cage)
Instead of replacing with a 10t-type FD, you could also fit a whole new chainset; in this case note that you have an Octalink BB (which is essentially an obsolete system Shimano introduced to save weight over square taper, and replaced with HT2), and e.g. T4060 is HT2 (new BB required), and T3010 is square taper (BB also required, but good-quality cheap square taper BBs are going to become harder to find, so this is not ideal).  If your BB is reaching the end of its life than you might go for HT2 as a replacement; if it's not, FC-T4010 48-36-26 would be a straight swap with no BB change needed.


SPD SL Cleat Cover, are they supposed to be attached all the time or removed on rides?

The whole point of cleat covers is to protect the mechanism while not riding, which requires that the cover covers the clipping surfaces. So, they need to be removed while riding. With Speedplay the covers are more important because the mechanism has most of the sensitive parts in cleat instead of pedal.

The Speedplay covers linked in comment do not actually cover the mechanism but provide a relatively walkable rubber sole over the metal cleat. Newer models have that part built into cleat and a separate plug for protection.


Where do I get this part for my v brake?

You're probably not going to find this part without cannibalizing a similar enough brake arm.

The parts you can find replacements for without having a sacrificial arm for V-brakes (*) are:

Noodle
Boot
Mounting Bolt
Brake pads/cartridges

If you need to replace/repair any other part of the V-brake, you're better off (and likely going to be) buying a new one.

(*) for most V-brakes; check the service manual for your particular model, though even if it is serviceable, you're unlikely to find the parts.

That being said, you might be able to make a suitable replacement on your own for the part in question with a bit of PVC tubing or some other plastic tubing cut to size and shaped appropriately.


How to improve my performance on a commute?

I posted a comment

  Slick tires would make a difference, if you're not using them. Maintaining 24 kph on a hybrid that you ride one day a week is pretty good. The next two increments after slick tires would be clipless pedals, riding more frequently, and then a road bike.

... but decided a full answer was needed.

Given that the trip is 24 km, doing it in 60 minutes is 24 kph. Not bad for a lightly built guy riding a hybrid that is reported to be heavy, one day per week. By my figures, you're putting about 150 watts into the pedals to do that. This assumes you're using wide, non-slick tires.

Switching to thinner, slick road tires would gain you 2 kph for the same effort, possibly 3 kph. That gets you there 5 minutes quicker.

But to put 150 watts into the pedals, you have to produce more, because without your feet being clipped in, they will slide a little, and you have to use energy to keep them in place. Lets guess that's 10% of your effort - 15 watts. So you're really producing 165 watts. That translates to about 1 kph faster if you were clipped in. But as the late night TV ads say, but wait there's more. With your feet clipped in, you can produce more power because you can pull the pedals up as well as push down. How much more? The experts argue. Some claim 15%, others 40%. If it's 15%, that's another 24 watts (15% of 165). So after your aerobic system has adapted to delivering that much extra oxygen, you'll be up to about 29 kph. But I think you'd need to be riding three times a week to develop that sustained pace.

Extra training can take you faster, if you are riding regularly. How much is up to your innate abilities and dedication.

And how to go even faster? A road bike. For the same power that drives you at 29 kph on the hybrid, you'll go at 31 kph on a road bike, getting you there in 47 minutes.

So, you said you didn't want to spend much money. I'm arguing that clipless pedals will give you good return. They also support you as you work to increase your strength and fitness.


What range of rotational speed for bike wheel bearings?

Searching for "ndm rotational speed" finds that D and d are outer and inner diameters of the bearing. n is not the usual symbol for speed, but neither is the final unit "millimeters per minute divided by pi" an usual unit. And here we go:

A slightly optimistic approximation for road bike speed would be 10 m/s (36 km/h, 22.5 mph) and wheel circumference 2 m. That gives us roughly 10 m/s / 2m * 60 = 300 rpm. The bearing track diameter is around 50 mm (slightly under 2 inches and yes, the sum divided by 2 is the average of inner and outer diameters).

All together this gives us 300 rpm * 50 mm = 15000 weird units. This is very well inside "very low" category for roller bearings, and you can double the speed or halve the wheel size before you reach the "low" category. For ball bearings, there is no "very low" category, and you need to exceed the approximation by factor 6.66 before you break out of "low" category. You can change all numbers involved in the calculation by quite large amounts, and the result will always stay "very low" or in extreme cases "low".


if you replace the front gear system do you need to replace both the rear casette and the rear derailuer or neither

You can completely change the front setup (shifter, cables, crankset and/or derailleur) completely independently of the cassette and rear derailleur/shifter with no problem.
If it's a used bike it may be worth checking the chain/cassette are not worn in case the do need to be changed (but would be unrelated to the fact that the front setup was changed)

Update -
As per comment from @batman, if the size of the crankset has changed the length of the chain may need to be updated also


What to put on or inside winter-SPD-boots to keep toes warm?

MEC advise, on their web site, that the cheapest way to keep your shoes dry is a plastic bag.

They also sell shoe covers: some for rain and some (with neoprene and microfleece) for winter.


What's your most useful cycle accessory?

Fenders/Mudguards - front and back.  I ride all through winter and these help keep me dry. There's usually only one or two dozen times a year that I'm really riding in the rain for my morning or afternoon commute, but there's a good 3 or 4 months where rain comes through often enough that I'm riding through a lot of puddles.The rear fender prevents the classic skunk stripe, while the front fender primarily prevents splashing onto my feet and ankles.

These also help keep your bike clean and should help increase the lifetime of your chain/gears (or at least give you an extra few days before it's time to clean and lubricate everything when riding in winter).

I don't remember the exact model, but they're basically these fenders from Planet Bike that include a mud flap.


I ride a lot of trails where it is almost impossible to ride up and sometimes not even practical to push the bike up, and it is easier to carry. I've got a full suspension mountain bike with no space inside of the triangle, so it is not possible to shoulder it. And carry a bike on my back, rather than on a shoulder. Bottom tube is resting on my shoulders with rear wheel on right from my head and front wheel on left from my head.

Like that:

It helps if you have a backpack, as the bottom tube rests on it. After some practice you can have both of your hands free, while bike comfortably sits on pack. This way bike does not get in your way and you can hike quite a big distances.

UPD: This position is not the quickest to put the bike up, but I find it the most comfortable when climbing. To get the bike up, stand on non-chain side of a bike, place left pedal (closes to you) in the lowest position, grab with one hand the left crank and fork stantion with the other hand. Lift the bike over your head and on your shoulder/backpack.


The most important part of a vehicle light is the optics because you want a beam with a precise shape and distribution in order to illuminate the road evenly, without wasting light into the sky or blinding people coming in the other direction.

These optics are very difficult and expensive to design. It is easy to make a circular lens which will throw half the light into the sky and blind people coming towards you. A proper beam, which results in even illumination of the road regardless of distance, has to distribute light in a special way which is very un-even: low power at close distances, high power at long distances, a sharp cutoff to avoid blinding other riders, and it has to have the proper pattern in the horizontal direction also:

This lamp costs € 189 which is quite expensive. These beam shots tell the rest of story. It is very difficult to do a sharp cutoff without wasting light.

Important: beam accuracy depends on the ratio between optics size and light source size. The smaller the light source the better. A tiny point light source would be ideal, and it has to be positioned accurately at the focal point of the optics. A larger light source can work, but the size of the entire optics assembly has to be scaled up proportional to the size of the light source. If the optics size is constrained (ie, you're not riding with a 8 meter wide telescope) then the larger the light source, the more inaccurate the result.

Now, you mention laser lights. The reason these are interesting for car lights is not the efficiency. No-one cares about the efficiency of headlights when the car burns tens of kilowatts just to move. Besides, I found a 160lm/W efficacy figure for laser headlights. LEDs can do that already. The interesting bit is that laser-excited phosphor lights can create a really tiny point source, which is what makes these excellent optics possible.

But do you need that on a bicycle?

If you travel at 250 km/h in a fancy sports car, you'll need a light that illuminates the road very far away, at least several hundred meters. But a bicycle is a bit slower, so most people will be happy with a light that allows them to see, say 50m ahead, maybe 100m going downhill, and that can already be done with LEDs at a much cheaper price than laser.

There is also the fact that an optic that can aim a beam at long distances has to be aimed where the beam needs to be, which means a computer and several precision actuators. Since a bicycle leans in turns there would have to be extra actuators to compensate for that. It gets silly very quick.

Conclusion: even if laser-excited phosphor lights get cheap in the future, their advantage is enabling fancy optics you don't need on a bike, not efficiency. LED efficiency is driven by very strong economic factors (ie, the lighting industry) so LEDs will get more efficient. I don't think you'll get laser bike lights anytime soon.


If you are doing this to get a better Enduro and a Better DH bike, I believe this is a really bad idea.  If you are doing it because its fun and you want to play and learn about bike building, dive on in, but be prepared fro less than stunning results at higher than expected prices.

Given the manufacturers are fully aware most people have an S ( refer  Rule 12 ) of 2 or 3, they spend a lot of time producing a wide range of bikes that in their range, there is one that will as close to a perfect  compromise of price/performance/style for everyone. Unless you are a very skilled rider, and a skilled bike builder (not assembler) I believe it's bordering on arrogant to think you can do better cheaper.

The other issue is the bike components them selves.  Would you rather have a $500 enduro fork and a $500 Down hill fork, or a single $1000 fork. My money is the single $1000 fork will do both jobs better. Same applies to wheels, gear sets.....

If you have done all that, and still feel the bike is the limit factor of your riding, you probably need two bikes.


Modern Retro-design (Peugout-mixte) bicycle for girlfriend

The first thing to do is find the local bike shops (preferably locally owned, not large multinational chains) and look around and ask around there. Try to check multiple shops, not just the first one you find, since they may specialize and you may find some easier to work with. Try chatting with the staff; if they don't carry what you're looking for they may know who does or be able to order it.

Since I don't speak Portuguese (or Spanish), it's difficult to see which bicycle companies distribute widely in your country. When I can figure out which ones have some kind of distribution into the general area, it doesn't necessarily mean that specific models make it into the country or into the local shop.

All the major bicycle manufacturers make "women's" bicycles with a step-through frame, fewer of them make ones that are a true "mixte", however.

But here's a few attempts at mixtes that may be available in Portugal:

Globe Live Mixte -- their website looks like they distribute in Portugal. Globe is a sub-brand of Specialized.
Giant Via 2 -- that's from the site for Spain, so likely also available in Portugal
Trek Belleville WSD -- Trek does seem to distribute into Portugal. This one's my personal favorite mixte of the big manufacturers that I found.

If you can afford it, another option would be to talk to a local framebuilder and have a custom bicycle made. I expect that almost any framebuilder could make a mixte (but they might have to special order some parts they don't keep stocked).


Bike derailleur, keeps flicking back when I pedal

I think we can rule out the chain being too long. The OP replaced the derailleur but does not state the chain was replaced. Also, that does not look like a clean and shiny new chain.

The chain is threaded through the cage correctly, it's just that the derailleur had rotated 90 degrees rearward so that the cage is sitting behind the sprockets rather then underneath them. If the derailleur was rotated back it's possible to see that the chain would run in front of the top jockey wheel and behind the lower one.

Here is my theory: the cage is not tensioning the chain, it should be trying to rotate clockwise under spring tension but is not. I think the cage was somehow rotated clockwise before the chain was threaded through it, unloading its spring.

To fix, remove the chain, rotate the cage anti clockwise so that its spring is wound up, rethread the chain through the cage and rejoin. The chain should be under quite a bit of tension when you join it.


I'd consider going back to square taper a bit of a downgrade. And buying a crank to suit the bottom bracket is a little bit backwards in thinking. That crankset you linked to would be fine assuming you want to keep the BB. FSA has been pretty good in my experience, but I can't say that with certainty for your case because I've only dealt with their more expensive stuff.

The thing you'll have to watch out for is getting the right chainline. If you have the wrong length spindle, you'll end up shimming something, which I never recommend unless absolutely necessary, or just buying a new one anyways. Without more information I couldn't make an assessment of the right length spindle for your bike. I didn't have any luck on FSA's website in finding their suggested spindle length to produce the standard 43.5 mm chainline, or whatever is appropriate for your case.

I would go order the correct BB if I was you, as long as you're willing to keep your crank for a little while longer. A new crank AND BB might be in order if you can afford it and want a smooth new setup. I don't know what you're doing though if those FSA BBs are only lasting 3000 km, though. I've had that exact same one, and it lasted so long I sold the bike before it wore out.


What road bike tire pressure is best for speed?

I generally agree with Angelo's answer. Tire diameter and your weight will determine the optimal pressure. Beyond that, this is actually a controversial subject.

Let's assume that you want to minimize rolling resistance. "Rock hard" isn't necessarily the best approach. One widely cited opinion is that above a certain pressure, there's no benefit in terms of rolling resistance, and the target is a 15% "drop" (vertical deformation under load)—it is argued that even with less drop than that (i.e., higher pressure) you do not see an improvement in rolling resistance, so all you're doing with that extra pressure is making the ride harsher.

Here are a couple of articles (pdf) discussing pressure, rolling resistance, and tire drop. You can see that there's a diminishing-returns curve in terms of power savings at higher pressures. The second one includes a graph showing how much you should inflate a tire to get a 15% drop depending on how much load there is on that wheel and how wide the tire is.

I should point out that this opinion is not universally held. Jobst Brandt, for one, is skeptical, but I'm not sure what he recommends.