What's the point in a freewheel/cassette with incrementally sized rings?

The point is efficiency.

Cyclists actually have quite a narrow optimal power band. Most of us can bang away at a cadence of 50 rpm, up to about 90 rpm. Some of us pedal faster - 90 to 120 rpm. At those lower cadences (50) it feels like we're producing lots of power and at the high cadences it feels like we're just breezing along. But that is confusing torque with power. The optimal power band is where we produce most power most efficiently.

How narrow is that power band? Take me as an example: 50+ years of road cycling, leg muscles well trained to buzz along at 100 to 120 rpm. My optimal power band is 105 to 115 rpm - on a flat ride I can do that for hours. If my cadence is dropping on a rise or into a headwind and I'm starting to grind, I know I'm down around 100. On a hill, after I run out of gears, if I can maintain a cadence of 90 or above I'm happy. But it's not as efficient.

So there are three factors to consider: the rider, the terrain, and the wind.

Terrain. On a flat road, close spacing gives us scope to choose the optimum gear. On a hilly road, we might want wider spacing at the bottom of the range to help with climbing. For MTB, AFAIK such a cluster would be unsuitable, but I'd welcome input from an MTB rider.

Wind. On a circuit, wind is like hills. Except that we always seem to have a headwind. Whatever. In wind a cluster with wider spacing helps.

The Rider. You. Where is your power band, and how wide is it? With training it will change. You'll hear many riders say that they "top out", meaning they couldn't pedal any faster (look at the tables below and see what that means). More factors come into it now: training and pedals. Pedaling fast takes practice, not just to pedal, but to do it smoothly so you don't bounce uncomfortably. And you have to be "clipped in" - no flat pedals.

But I digress. A general purpose 10-speed road cluster for a strong rider might be

  11, 12, 13, 14, 15, 17, 19, 21, 23, 27

The difference between each gear at the top end (11 to 15 teeth) is between 6% and 9%. At the bottom end, the difference is about 10%, except for the "granny gear". Taking our narrow power band into consideration, and assuming we have 39x53 front chain rings, that means we'll be able to find a comfortable gear at a wide range of speeds.

On the 39T chain ring, at 90 rpm (as an example; it's the ratios that matter, not the exact cadence):

  19 kph on the 23T sprocket
  21 kph on the 21T
  23 kph on the 19T
  25.8 kph on the 17T
  27.5 kph on the 16T
  29.3 kph on the 15T
  31.4 kph on the 14T
  34 kph on the 13T
  37 kph on the 12T
  40 kph on the 11T

And still on the 39T chain ring, at 110 rpm:

  23 kph on the 23T sprocket
  25.5 kph on the 21T
  28 kph on the 19T
  31.6 kph on the 17T
  33.5 kph on the 16T
  35.8 kph on the 15T
  38.3 kph on the 14T
  41.3 kph on the 13T
  45 kph on the 12T
  49 kph on the 11T

So, if you were riding at 30 kph, you could choose from the 15T cog, the 16T or the 17T. One of them will (in my case the 16T) be closest to your optimum cadence.

Switching up to the 53T chain ring, at 90 rpm:

  26 kph on the 23T sprocket
  28 kph on the 21T
  31 kph on the 19T
  35 kph on the 17T
  37 kph on the 16T
  40 kph on the 15T
  43 kph on the 14T
  46 kph on the 13T
  50 kph on the 12T
  54 kph on the 11T

And still on the 53T chain ring, at 110 rpm:

  32 kph on the 23T sprocket
  35 kph on the 21T
  38 kph on the 19T
  43 kph on the 17T
  46 kph on the 16T
  49 kph on the 15T
  52 kph on the 14T
  56 kph on the 13T
  61 kph on the 12T
  66 kph on the 11T

So now, considering that we have both chain rings available, you can see that at 30 kph you have 2 more possible gears. So depending on the terrain ahead, you would choose the big or small ring and the appropriate back cog.

For even stronger riders, the bottom gears are only 21 and 23, or maybe as low as 25.

Hope that helps!


The brake pads on this kind of brake (V-brake) are adjusted with the screw above the one you've circled. The screw at the end of the pad adjust the positioning of the pad relative to the rim. It's one of the jobs where you ideally need 4 to 6 hands to get it right.
The screw that you circled adjusts the symmetry of the pull, or the timing of the pads touching the rim by adjusting the tension of the springs in the pivots.


Why would a bike computer calculate distance accurately but average speed inaccurately?

Okay, this actually requires some knowledge of how these little computers work internally. Bicycle computers need to be extremely low-power, so the easiest way to do this is to make them very simple. Normal computers are able to use non-integer numbers. An integer is 1,2,3,4, etc., non-integer means for instance 1/2, 0.5762 or pi. Computers use so-called floating point numbers to represent non-integer numbers.

However, floating point numbers are very hard to use for these small computers compared to integers. So, they don't! They only use integers to do all necessary calculations, and with very little exceptions they are all limited to 8-bit integers. An 8-bit integer can store a value of 0-255. So, any calculation will (a) not be more precise than a whole number (e.g.: dividing 8 by 5 will yield 1 instead of 1.6 because you cannot represent numbers behind the decimal point) and (b) cannot exceed beyond the range of 0-255.

It's even worse: most bicycle computers can't even do math. Well, they can usually add and multiply, but they cannot divide or subtract. They are really super bare bones stuff, because they have to survive for a couple years on the juice in a single coin cell.

So, how does this affect the calculation of distance, speed and eventually average speed? Well, a bike computer has only 2 inputs: a very precise timer (usually outputting between 1024 and 32768 pulses per second) and a pulse input from a magnet on your wheel. It also knows how long the circumference of your wheel is. So, in order to calculate your current speed it does the following:

wait for a pulse from your wheel
start a timer
when the next wheel pulse arrives, stop the timer
divide your wheel circumference by the time and use a lookup table to convert this into something human-readable.

So, let's say the timer runs at 1024Hz and your bike wheel turns at about 5 rotations per second (36km/h or 22mph). This would mean that you would count floor(1024/5)=204 timer ticks per wheel rotation. In the little processor is a lookup table that relates those 204 ticks to your specific wheel size (which you programmed in) and then finds what speed needs to be displayed on your screen. It doesn't actually calculate it, because it's very hard for that processor to do such things. Besides, this table only needs to be a couple wheel sizes by a few tens or maybe 100 different time values. For instance a 5x100 table, pretty small in computer terms.

Distance is very easy to calculate: just multiply wheel circumference by the number of rotations. Then use another lookup table to relate this to something displayable. This too only requires a small lookup table.

However, average speed is not something that can be put into a reasonable-size lookup table. There are just too many possible trip distance and trip time values that can occur. So these computers have to cheat somehow: either they need to use the very limited math capabilities they have, or they need to round some things down or look for the nearest average value. This is exactly what your bike computer is doing.

There are more advanced bicycle computers, especially nowadays. With older designs, you could really see this lookup table-nature of operation: it could display for instance 22.3 km/h and 22.5, but not 22.4. Why? It was not in the lookup table. No matter how hard you would try to ride exactly at 22.4 km/h, it would never actually display this value. Also, older designs would only allow you to enter the inch-size of your tires, not the actual precise circumference in mm.

Nowadays, there are actually bike computers that can handle more 'complex' mathematical operations and use better number representations (either 16-bit integers or floating point numbers) to get to a better estimate of your speed and averages.


4 year old alivio 8 speed rear gears - compatible chain

No, all 8 speed chains are not compatible. For that matter, neither are all 9 speed chains. But for practical purposes, they will be within tolerance to work well enough. Ideal shifting is best obtained with all components being of the same design, in good condition, and good adjustment.

The chains you linked to: There are 2 types of Shimano 8 speed chains. The common one, HG or Hyperglide and IG, or Interglide chains, which are not designed to work together.

If you have HG, and buy a shimano chain, you should get an HG chain.

SRAM chains have looser tolerances, so any 7/8 speed chain will do as well as any other.

I am not saying you can't use any 8 speed chain. Only that some will shift better than others.


It's probably fine, especially if it's 4130 or something similar, as opposed to a heat treated and/or air hardening tube.

From one picture and without hands on it I wouldn't necessarily recommend this, but such damage on steel frames can often be more or less repaired by putting in a stout seatpost of the right size, wrapping the area in a rag, and going to work on it with a rubber mallet. One good reason to do this would be if the deformation was partially bulged inward and the seatpost wasn't moving very freely, or making bad contact and tending to slip.

It appears that there would be room to cut off the end and extend the slot, but since the deformed part in the picture isn't at the top anyway there probably isn't much point. If you were finding that a seatpost goes in rough because the whole top part of the seattube is bent backwards, then this could perhaps make sense. It's critical you preserve a long enough slot in order for it to be able to clamp. Framebuilders have a minimum slot length worked out; I've seen it mentioned but I can't find it right now.


Here's a photo of sealant failing inside a tyre.  These are the latex molecules lumping up together rather than staying in suspension in the carrier liquid which is glycol-based but varies by brand.

These have the glorious name of "boogers" and are a sign the sealant is not going to work very well.  This tyre should be cleaned out completely and a new serve of sealant added.

This is what should happen at the hole when a tyre punctures.

The carrier is either a water-based glycol/propylene with cellulose and thickener agents like aramid/ceramic fibres, or non-water based latex mix which doesn't need extra thickeners but does have a limited effective life.  Latex also has some level of Ammonia which can contribute to corrosion.
Either product will distribute around the inside of the tyre while you ride.  This leaves a thin layer waiting just inside the area where the puncture forms.

The lighter-weight carrier fluids exit the hole along with the escaping air.  This leaves a visible wet spot on the outside.

As the carrier flows through the hole with the air, the heavier/larger suspended particles get stuck and form a blockage, which slows the air leakage and eventually seals.   In theory, the plug will flex and more air will leak, but the sealant will do the same, continuously packing into the weak spots and stopping the leak.

This only works if the sealant is liquid.  The carrier is volatile and will bleed out through your tyre over time anyway, leaving a dried mess in the tyre.  If your bike is not ridden much, the sealant will pool at the bottom and that's not a lot of use plus it will unbalance the tyre.

Many sealants can be re-energised by adding more fresh product, but mixing brands is an unknown because the chemistry will vary between brands.  Best to dismount the tyre and do a complete clean before changing brands.  Some riders recommend changing tyres every 12 months regardless of wear.


If You are DH racing, then we are talking about racetracks and trails that are known to the rider, assuming that the rider is practicing and getting used to the track, picking best lines for each section and generally speaking, creating/refining a race strategy.

In that context, a gear is to be selected according to the particular needs of each section, taking into account:

The entry speed for the specific rider on the section.
The needed exit speed for the section. (Next section's required entry speed)
Length of the section.
Roughness and slope of the section's terrain.
The "tiredness" level of the rider upon arrival to the section.

Let's elaborate a little:

Entry and exit speed define whether you need to accelerate, sustain speed or decelerate. With that in mind, To accelerate you need a gear that gives a slightly slower than ideal cadence, because when pedalling the ideal cadence would be reached and then surpassed. This assumes only one gear is needed for the section. If more gears are needed, then the shift should be made as soon as the cadence is felt to be over the ideal. (The purpose is to be near ideal cadence as long as possible.) If speed is to be sustained, then select the gear for the rider's ideal cadence at entry speed.

Length of the section dictates if pedalling is even possible or if it means pedalling so long that XC pedalling technique is better suited. It also influences the number of gears needed.

Roughness also defined by whether it is possible to pedal or if it's better to focus on guiding the bike. Generally, the rougher the terrain the lower the gear. "Long" gears are better suited for smooth sections. The slope ash an obvious role: the steeper (downwards) the slope, the higher the gear, the steeper (upwards) the lower the gear.

Roughness and Length of the section together may also define if a "Pumping" or "Milking the terrain" technique is better suited for speed gain/sustain.

Pumping is pushing down the bike over small descents in the terrain and pulling up in the small ascents. If the sections has many of these ups and downs, then you "pump" the bike up and down as you pass over the undulating terrain.

Milking the terrain is a more broad term that implies taking advantage of terrain irregularities to gain speed. For example, instead of rolling over a rock, use a previous rock to jump and land on the "descent" part of the next. The energy from the landing combined with the slope will push the bike forward.

(I know for sure that you can search videos for "pumptrack" and you'll find deeper explanations on these techniques).

Finally, the tiredness of the rider while arriving to the section play a major role on gear selection, even if overlooked. A DH race strategy has to deal with rider's energy dosage. Sometimes it is better to "rest" on a smooth section, to have arms and legs ready for an oncoming rougher section. Also, for some riders it is true that they pedal better on high gears when tired and better on lower gears, high cadence when fresh, for others, it may be the opposite, so, it is not the same if the "flat" section is at the beginning or at the end of the racetrack.

In my particular case, I tend to begin on a mid range gear, to accelerate faster on the race start, and sometimes keep a rather low gear because it is more likely that the pedalling section will have a slow entry speed. As I go trough these sections I progressively shift to higher gears and let it stay there, because I happen to pedal better on higher gears when I'm tired.

Of course, each trail or racetrack is different, so when I'm practicing, I note the gears I use, and try to decide whether each particular section is doable on a different gear. If I do my homework correctly, the race day I have cleared which gear should I use for each section. I do not memorize gear numbers, instead I recall what gear I decided was better for start and memorize the parts of the track where I have to upshift or downshift.

Almost forgot! Type of pedals may play a role too: I started to race DH on a XC bike with cleated pedals, I had been using them for XC for years, but when I got my DH bike, It had Platform Pedals. After some doubt and several races, I installed cleats on that DH bike and my times got a lot better in part because they allowed me to pedal faster (higher cadence) than the platform  ones. Also allowed me to pedal on rougher terrain and generally allowed for better bike control.


Suitable rear mech for Megarange cassettes

It will probably work.  The one thing you need to look at is the length of your derailleur cage.  With that really large cog, you might have to adjust your chain length, and then your derailleur might not be long enough to properly tension the chain.


Steel road bike with frame that hides cables

I wonder if you were looking at the macho man disc, which has a steel frame and only comes in white/red:

http://allcitycycles.com/bikes/macho_man_disc


Why do rear pannier racks have a raised "nose"?

I think you are correct that it’s only to prevent items from sliding forward and falling off or colliding with your legs/hips. This is only really important if you use the spring loaded clamp. A lot of racks (I think all of them without the spring loaded clamp) don’t have this “nose”.

Since there is still another horizontal bar right below it I don’t think removing it will affect stability. Just make sure to cut it cleanly, remove any burrs, plug the hole and apply some paint to prevent rust.


Yes, this is no problem, though I would suggest practicing once before you have to use it on a flat. The first couple of times I used an inflator I had trouble inflating my tire fully.
No, but I've found that once I start a cartridge it will leak slowly, so it doesn't last forever. In my experience it doesn't last more than a few hours, certainly not more than a day.
You can buy inflators that handle both threaded and unthreaded. For example, this one -- http://www.amazon.com/gp/product/B00278XO0Q -- can take any 16g CO2 cartridge.


How do I reduce slack in the chain of a single-speed bicycle?

If you have horizontal dropouts (the wheel axle slides into the frame from the back of the bike) the dropouts have long slots which will allow you to pull the rear wheel back and take slack from the chain.  Be careful to ensure when you torque the wheel nuts down the wheel doesn't slip from being aligned straight, or the chain is running at a slight angle.

If the chain is so stretched to the point where it's falling off, you really should consider replacing the chain.  You can get away with removing a link to remove the slack but a worn chain will be prone to sticky links and popping off unannounced.


How do I determine the correct position for my bicycle seat?

For a quick fit, the general goal is to keep the seat high enough that you can get a nearly-full leg extension, without 'locking' the knee.

Over a long period of time, if you find that you are having knee, foot or hip pains, try making small adjustments with the saddle, about 0.5-1.0cm at a time, either up, down, forwards or backwards. If the pain gets worse, try the other direction. Give it some time, and eventually you should find a painless position.

A tip I recently got from a friend having a similar problem proved interesting: Those of us who are males typically 'dress' right  or left. For him, aligning his saddle with the nose turned slightly off-center (away from the direction of 'dressing') alleviated all of his knee discomfort!


What causes and how to fix wandering bite point on Shimano hydraulic brakes?

Originally I gave a tentative answer to this question and proposed the solution without actually trying it (next three paragraphs), and now that I have tried it I expand the answer with a report on the results (last two paragraphs). Spoiler: as already verifed in the meantime, the solution works perfectly.
Firstly, this is not a bleeding problem. I verified this by thoroughly bleeding the brake using fresh original Shimano mineral oil, after first draining the system to make sure I really do use the proper fluid in good condition. I also took the opportunity to clean the pistons and "lube" them a little with the braking fluid, just to eliminate dirty/sticky pistons as a possible cause of the problem. The bleeding was done at room temperature and the results were excellent; great lever feel, sharp engagement, consistent bite point position. However, after I took the bike for a test ride through the neighbourhood, with the outside temperature just around freezing, as the system cooled to the outside temperature the wandering bite point reemerged, i.e. the lever would "pump up" (engagement would begin earlier). The corresponding effect, to a smaller extent, emerged at the front brake as well.
Given this test and the information I have gathered at various places on the web, I conclude that the cause of the problem is the high Shimano mineral oil viscosity at low temperatures (viscosity being, in layman's terms, the resistance of fluids to flow freely; water has very low viscosity and flows easily, while e.g. honey has high viscosity and oozes slowly), combined with the small orrifices of the Shimano levers' inlet and compenstaing ports through which oil flows between the master cylinder and the brake fluid reservoir. Namely, instead of the oil flowing to the reservoir through the compensating port as the pistons are retracted after braking, the oil stays in the main line, so as the lever returns the pistons do not yet retract fully, meaning that on the next braking they are extended closer to the disc and therefore bite sooner, with lever further from the handlebar. If given more time, the oil slowly flows back in the reservoir, the pistons retract fully, and the bite point returns to its usual position. Hence, the bite point wanders to the outside by amount dependant on how often you engage the brake; at low temperatures, you can pump up the lever so that there is almost no free stroke before engaging.
The solution I have read about and intend to apply is to swap the original Shimano mineral oil  with a low viscosity oil that has small viscosity variation with temperature (i.e. a high viscosity index or VI; Shimano's VI is pretty low, apparently, meaning it gets "sticky" at low temperatures). I believe this nullifies the warranty, but I have found there are many people, especially in Germany, who have been doing this for years using one particular motorcycle fork oil. In fact, this is so widespread that this oil, Putoline HPX R 2.5, is considered a benchmark on their forums, and if you try to buy it on German Amazon, at the time of writing 7 of the total 8 reviews rave about its use in Shimano brakes, the eighth also lists this as one of the uses it is good for, while Amazon auto-suggests Shimano bleeding funnel as an additonal item to buy with this moto fork oil (!).
After I actually try this, I will update this answer with a report on the results.
UPDATE: Roughly a month ago I finally bled my rear brake with Putoline HPX R 2.5. The bleeding was as easy as usual if not easier, as the less viscous Putoline fills the lines more quickly. Since then I have had several snowy rides at temperatures well below freezing, down to under -6 °C (under 21 °F). The wandering bite point dissapeared completely and the bite point became perfectly consistent, i.e. the lever neither pumps up nor sinks. I cannot even reproduce the wander deliberately by successively puling the lever as fast as I can while standing over the bike, let alone while riding. For comparison, I still use regular Shimano mineral oil in my front brake, and now that the rear brake is completely wander-free, even the small „pump-up“ I previously felt in the front feels huge. As for the performance at warmer temperatures, the highest in the last few weeks were about 15 °C or 59 °F, and the brake felt great. Apart from achieving predictable and consistent bite point in the entire range of riding temepratures, I could not really feel any difference compared to using Shimano oil; the lever action on both sides feels firm and safe. As for the seals, there are no indications of any adverse effects of Putoline whatsoever, let alone leaks.
Given this experience, which has now also been confirmed by others (see answer by Gareth D), and the fact that Putoline is also cheaper than Shimano mineral oil, I can only recommend using Putoline HPX R 2.5 as a solution to the wandering bite point problem to anyone not worried about the warranty of their Shimano brakes. Come next bleeding, I will start using it in the front as well.


What are the pros and cons of panniers vs messenger bags?

A messenger bag is great when you:

Are not transporting a heavy load
Have to put items into the bag, or remove items from the bag very often.
Are doing short trips, or having to leave your bike a lot as part of a longer trip

A rucksack is great when you:

Wish to be able to easily carry the load while off the bike
You have to walk a long way after your bike ride, or use public transport
You wish to have both hands free when not the bike, e.g you need to carry the bike up stairs at the start/end of your trip

Panniers are great when:

You care more about the “on bike” part of the trip than the “off bike” part
A pannier can have a solder strap, but it still takes time to fit and remove the strap or tie it up so it does not catch in your wheels.
(You will need some sort of rack to fix the Panniers to)

A basket is great when:

You wish to transport a normal bag (or rucksack) on your bike
You like the fact your the bag can be removed quickly by you (and don’t mind that it can be removed quickly by others.
You think being “practical” is more important the being “cool”.

A luggage carrier / rack is great:

When you wish to fix a bag or box onto the back of your bike
Unlike a basket you need to use straps (sometimes build into the rack) to fix the item to the rack.
You are less likely to get laughed at with a rack then a basket.
So it takes longer to fix something onto a rack then put it into a basket, but also it is harder for someone else to remove the item.
(Panniers are fixed to a rack; this is covered under the pannier section)


Getting started with carbon fiber DH/XC wheels

For XC you can find a myriad of wheels that are now carbon.

For DH, you can find some examples but they are big money.

They're typically more expensive than their aluminium counter parts, but a little lighter. Rotational weight is typically reduced, which will make the bike turn more quickly and feel "snappier".

Since you're new at mountain biking, I wouldn't recommend getting top spec stuff right away. You're going to have "oops" (e.g., wrong trail, endo, rip a dérailleur off, etc) and it would put a serious dent in your pocket book to replace carbon wheels. You can get two decent bikes for the cost of some carbon hoops.

Carbon typically isn't as forgiving in crashes because of the nature of the element. It's more prone to damage from impact than aluminium or steel counterparts, and the failures can be much more difficult to detect. Just my 2 cents.


Yes, it's a known problem, at least to me. The work-around is not to signal, or to use head-turning and lane positioning as a signal.

What I do is very dependent on the situation. In the worst case, fast moving traffic on a busy, multilane road with no bike lane/bus lane/parking that would allow me to slow down out of traffic I will overshoot and just pull in at the next opportunity. If I knew about it in advance I'd avoid that road. My experience of signalling and slowing down, forcing the moronist behind me to also slow, is that it doesn't help. I get signals back, shall we say.

Cyclists in Melbourne do signal more than they do in Sydney, but rarely to motorists. The most common is the right arm out "I'm pulling out in front of you" which when done assertively works almost all the time for persuading motorists to let you turn. (left arm/move left for countries that ride on the right hand side of the road). The slowing down signal I don't recall ever seeing except in primary school.

Signals between cyclists are much more common, but that's because they're safer, easier and the following cyclist is more likely to notice them.


In that context, Top sprocket is the smallest one on the cassette, which gives you the Top or highest gear.  (You would think they would match terms Low and High or Top and Bottom.)


If the bicycle has a rigid fork now and this fork is not marked as having "suspension-corrected" dimensions, in particular, axle-to-crown length, then this bicycle is not officially compatible with any suspension forks. Simply put, installing such a fork will either raise or lower the front of the bike, which will affect its steering properties and ground clearance among other things. There may be other problems, like the new fork's crown touching the downtube when turned.

If the current fork is "suspension-corrected", then it should be possible to replace it with a suspension one. Bikes of the era rarely had suspension travel more than 100 mm. There are other compatibility parameters to consider though, like steering tube diameter and shape, wheel axle type, brake system etc.

A bigger issue is, however, that 26"-wheels and accompanying components are (unjustly IMHO) considered obsolete by the market. It is hard to get new good parts for them, as most of new MTBs are sold with either 27.5" or 29" wheels. Those few cheapest new bikes with 26"-wheels out there are coming with OEM forks (i.e. those cannot be bought separately), and those forks are not especially known for their stellar damping properties.

The dirt jump bikes are however fixed to the 26" wheel size. It should be possible to get an aftermarket fork with 80-100mm travel for them. However, as I mentioned before, they tend to have modern "standards" elsewhere, such as through axles, tapered steering tubes and disc brakes, things not known in 1990's.


Painful Feet: Might be related to pedal-foot positioning

Definitely open to debate. Steve Hogg has some good information about cleat position.

http://www.stevehoggbikefitting.com/blog/2011/04/power-to-the-pedal-cleat-position/

and arch supports.

https://www.stevehoggbikefitting.com/blog/2011/02/foot-correction-part-1-arch-support/

I suffered from something called hot foot and using corrective insoles relieved me of all pain.


Cannondale CAAD12 headset proprietary or replaceable?

The CAAD 12 uses sealed cartridge bearings which are replaceable and not proprietary.

You shouldn't need many special tools to service the headset bearings, especially if they are new - you should be able to tap them out and remove the necessary parts with a screwdriver or wedge.

However, if you are asking the question because you are concerned with home serviceability, you will need a press to do any work on Cannondale's BB30 and BB30a (CAAD12) bottom brackets, which need service more than the headset.  There are videos out there of people doing it without a proper press, but it's risky.

Below are some pictures of a sealed headset bearing removal, similar to the CAAD.  Also, there is a picture of a makeshift press that you could use for servicing the bottom bracket, if you don't want to spend an exorbitant amount on the park tool BB30 press.

Bottom Bracket Removal Tool and Press:


Old Man Mountain sells a kit (PH-SH-F-THRU-BLUTO) for mounting their Phat Wide Sherpa Rack on the front with a RockShox Bluto fork (which your bike has).

To quote the page:

  Phat Sherpa Front with 15mm Thru Axle (For Rockshox Bluto). Comes with Robert Axle Project replacement thru axle and all other parts needed for installation. Part Numbers included in this compilation: PH-W, FK-5F15, AX-15BL, QRXLR170, EX6, CL1.5

Alternatively, you can look at their selection of rear racks.


Yes, very nearly all, if not all shock pumps certainly do use a schrader valve.


What kind of crankset to get for this bike?

Sounds like a poorly assembled bike to me - I reckon its a warranty job if it came with pedals installed.

If you installed the pedals yourself, then you didn't do them up tight enough, and they've stripped the threads.... though a month is quite quick for that to happen.

Are you sure the pedals and the cranks had compatible threads?  Not a 9/16" and 1/2" mashed together with force?

To answer your question - you need a ruler.  It looks like a 175mm long alloy crank with a 5 leg spider.  If the warranty doesn't cover it, you'll need to remove the crank, and take it to a LBS.

Tools you'll need:

Crank Puller
14mm socket to get the nut/bolt out of the middle.
Whatever fitting the five chain bolts have - possibly a hex head/allen or maybe torx.

Or get the LBS to do the job, and to give the whole bike a once-over for safeties sake too.  I see in the Amazon link comments like "returned, pedal wouldn't thread in the hole."


You just need to use a thin layer of grease to prevent bonding between steel and aluminum. Also if you’re having great difficulty when removing the crank arms, spray some liquid wrench in there and wait. Make sure that the puller is fully screwed onto the external crank arm threads to avoid stripping as opposed to partially screwing them on. Finally, remember that force over time means that applying less force over a greater period of time is equivalent and often greater than a large amount of force applied all at once I.e. strong arming. What that means is that you can set up some tension on the puller and leave it, and just keep applying a little more tension if it still won’t budge. Almost like magic, it will give way eventually.


Can I upgrade to Synchro shifting on a 10s Di2 bike? (Ultegra 6770)

I just installed a Di2 6770 10spd front and rear derailleur with a BT-DN110 internal battery.

I can confirm that once I update firmware on all the components, eTube does NOT allow me to set up synchro shifting.

Very disappointed considering the battery has all the hardware necessary to support it.


Mixing 9-speed Tiagra and 9-speed Deore XT

Yes, that will work just fine. I have a similar setup on my touring bike, Tiagra shifters and an LX derailleur.


Gatorskin Wirebead vs Folding (Which gives a smoother ride)

Folding bead alone will not affect your ride in a notable manner.
Here are some things which will affect the ride a lot more than whether it's folding or wire bead:

Tyre width (bigger = smoother)
Tyre pressure (lower = smoother)
Rim width (wider = smoother)

The difference between folding and wire beads are not really about comfort.
You could argue that the sides of a folding bead tyre are a bit softer than one with a wire bead, so if the tyres are the same or similar price, go for folding. Personally, I have not noticed the difference between my folding and wire Gatorskins.


Are there any major drawbacks to using a track frame as a frame for a fixed-gear or single-speed commuter?

Real track bikes don't have brakes. You need brakes for commuting, especially in a city, and at least 2 independent braking systems. Not all frames and forks have brake mounts. You also won't have fender or rack mounts which are nice in wet weather.

Ergonomics and geometry can be an issue, given that track bikes tend to be a bit twitchy and aggressively positioned.

A lot of people use them in an urban environment, probably because of fashion and some sort of bike messenger fantasy.


Converting road hydraulic disc brakes to flat bar : Possible?

The official answer from Shimano as of now is no, as per their road hydraulic systems compatibility chart.

Someday there may be flatbar road hydraulic levers that make their way onto a new version of that chart, but for now bikes like that just come with conventional MTB/hybrid systems.

There may be combinations that work acceptably, but they will be hacks in an area not a lot of exploration has generally been done in at present.

Matching fluid displacement is not simply a matter of the new lever moving at least as much total fluid as the old one. To perform correctly, the lever has to move fluid at an appropriate rate per distance of lever travel. Hydraulic brakes have a similar version of leverage (aka mechanical advantage) considerations as cable actuated brakes, or at least they would if in practice they weren't mostly black boxes in terms of observing and comparing displacement numbers.

In other words, if you hooked the caliper up to a lever that moved a bunch more fluid, the brake would feel firm and positive at the lever, same as hooking a v-brake lever up to a sidepull, but it wouldn't be generating correct leverage, and stopping power would suffer.

If you go the other direction, less displacement, you get a brake that generates a ton of leverage but the pad movement will be less than what it should be, so it will be prone to issues with the lever bottoming on the bar prematurely, and will feel mushy.


This is a fixie that was most likely built from a diverse set of components.

Frame and fork look like an road bike from before 1985.

The handlebar was most likely not from the same bike. It is typical for old roadsters a generation older.

Rims have eyelets and a trapezoid cross section. That would fit to 80s to 90s. The hubs have those peculiar high flanges with holes to reduce weight. That looks very much like early 80s.

Not enough detail in brakes. The style was used from 70s onward. Brake pads are new. Brake bolt seem new as well.

Brake cable outers look as old as the frame. That speaks for a home built fixed gear conversion. Shops would likely replace parts that are cheap and ugly (and possibly unsafe) to make it more attractive on storefront display.


TdF: How does putting one team member in a break away help the rest of the team?

The full answer depends exactly on the teams involved and the composition of the break but, in general, the key to understanding this isn't physics as much as it is game theory.

In a race like the TdF, there are many separate competitions being run simultaneously: not just for the overall General Classification but also for stage wins, the (green) points jersey, the (polka dot) mountain jersey, the (highest ranked rider under age 25) white jersey, the team with the lowest cumulative time, and so on. Not every team has a GC hopeful, but every team has a goal or goals. If your goal is a stage win, or to get one of your riders a particular jersey, getting someone into the break can allow the rest of the team to shelter in the peloton, conserve their effort for the entire day, and prepare for the next day's stage.

A more complicated case is when you do have a GC contender and also someone in the break. Depending on the composition of the break, your break rider can be threatening some other team's goal of a jersey. In that situation, you're playing a waiting game (a game of "chicken"), to force the threatened team to chase the break, while your team shelters in the peloton, conserving their effort for the entire day.

Sometimes a GC-contending team will put a rider in an early break with a set plan to drop the rider out of the break later in the race to help the team's leader. It's like caching supplies farther up the road that they can draw upon if needed.

Sometimes you have a GC contender but no one in the break, and the break composition threatens the secondary goal of another team. If so, you can wait until the other team starts to panic and initiates the chase, then shelter in the peloton, conserving your effort.

Teams will always look at the riders of an early break to determine whether its composition fits their goals. If not, the team will chase early to absorb the break, then wait until a different, more acceptable, break forms; in which case they will allow the break to continue while they shelter in the peloton and wait for someone else to panic and initiate a chase.

As the stages count down in one of the Grand Tours (the Tour de France, the Giro d'Italia, or the Vuelta a Espana), teams that still haven't yet won a stage become more and more desperate to get someone into an early break. There can be several re-shufflings of break compositions as the directeur sportifs try to get at least one rider into a stable break. That can be miserable for already tired riders as they accelerate again and again to claw back unsuitable breaks.

There are 20 teams on the road simultaneously each with different goals and skill sets, with many different sub-competitions. In terms of n-person game theory, cycling allows (encourages) temporary coalitions, collusion (as when members of different teams in a break work together to stay away), side payments (not only of money but also of agreements not to contest a sprint or mountain point), prisoner dilemmas, bluffs, feints, and tops it off with reneging. Then they have to do it again the next day, remembering whether a particular team carries through with its promises. This is the reason why mass start bicycle racing is, from both a strategic and tactical perspective, so much more complex than sports that feature only two teams facing each other on a field.


Rear bike stand attached to the axle bolt: safe?

They're totally fine because you only use the stand when the bike is stationary. That way the stand only exerts a force on the bike when its stopped and parked.

There are possible issues:

If the stand acts as a washer under the axle nut, it can possibly interfere with proper seating of the nut.  Notice many nuts have a serrated or textured edge to help bite down a bit better.  A hard steel washer will reduce that bite.  This will permit the rear wheel axle to move causing brake/frame rub.
Rear weight - the stand adds weight behind the rear axle, so it contributes to unweighting the front and adding that weight to the rear wheel.
Trailer interference.  Most trailers clamp to the rear axle somehow.  A rear axle stand will interfere with any trailer clamp.
Pannier clips - your rear panniers will probably have a low clamp.  The rear stand may obscure or shrink possible hooking points.  On the other hand, the rear stand may offer additional new hooking points.  Deploying the stand may be difficult with a left-side pannier fitted too.

There are positives.  Your stand is near the panniers so it is closer to the Center of Mass when the panniers are loaded.  By comparison, a BB stand is more centered on the bike.

Personally if you don't care about weight, look for a dual-leg stand.  They're a lot more stable for loading the bike.  Downside they're heavier, require a chainstay bridge with a mounting hole, and can interfere with the cranks or lower chain stretch.


I want to replace 52/36 chainrings with 50/34 chainrings on a Praxis Works

Looking at the road Praxis chainrings page, 52/36 through 48/32 ring sets are all offered in 110mm BCD. All the roads cranks seem to have an evenly spaced 5 bolt pattern.

Without knowing exactly what crank you have I can't say for sure, but it seems likely you can fit smaller rings.


Shimano Nexus 8 internal hub skip/clacking noise when under torque

There are some Nexus and Alfine bikes that have made it out into the world with a spec mismatch between the over and under style cassette joints and the shifter.
The cable pull sequence works in reverse order between the two shifter types. Because the cable pull for this system varies with each click, everything gets screwed up if you then use the setup marks. Something like what you're experiencing can result.
To check this, get your exact cassette joint and shifter models and make sure they're listed as compatible on si.shimano.com.
If that checks out, test it with less belt tension.
If that's not it, get oil dunk gear and the Nexus/Alfine notchy tool, pull the core, wipe, inspect for anything out of place or prematurely damaged or worn, dunk, grease, reassemble, and see if that fixes it.
One perfectly likely explanation is that the pawls that drive the shell are having engagement problems. If one or more is under-lubricated, deformed, or out of place, it could cause a partial engagement problem, which also fits the symptoms. This can lead to a situation where the tips of the pawl(s) get damaged and the problem gets worse. This is easy to inspect for once the core is removed. Note that despite the ostensible complexity of the hub, the pawl system in question is the most exposed part of the whole deal, being the interface between the drive ring inside the hub shell and everything else. If it does the same behavior with the cable disconnected completely, I think this pretty likely is what's happening.
It is true that everything about this should be covered under warranty. Between parts shortages and the usual awkwardness of getting warrant support to happen for mail order bikes, it may get hairy at the moment.
Also check dropout alignment slash sync up slider fore/aft if applicable, all of which can in theory cause hub badness.


Daily commuting - are dietary supplements recommended?

The canonical recommendation is for "a complete and balanced diet". Whatever 'supplements' you might need depend on what your current diet is. The recommendations I've been given (I'm 50 and commute 24 miles/day) from a dietitian are vitamin D (because I live in Canada - I suspect that recommendation is obsolete currently while I'm commuting 2 hours/day in summer) and (based on blood test results) perhaps a bit more iron (I'm vegetarian). Some of the important components to consider, IMO, include water, salt, carbohydrates, and, rest/sleep. In summary, perhaps you should talk with a doctor or dietitian.

If you want to discover what your current diet is (which is presumably one important question before deciding how to supplement it - an alternative might be physical exam, blood tests), I quite recommend DietOrganizer.


3mm is definitely not enough, especially with plastic fenders!

A good rule of them is your fenders should be at least 10mm wider than your tires. I run 42mm tires on one bike and it has 58mm fenders. On my other bike I run 32mm tires and 45mm fenders. You also want at least 12mm between the inside of the fender and the tire. Ideally, you should have 20mm between the tire and point on the frame the fender bolts to (to account for fender thickness, protruding bolt heads and mounting hardware).

Keep in mind poorly fitted fenders can be a safety issue. If an object gets kicked up into the fender it can cause a crash.

Some good articles on fenders: https://janheine.wordpress.com/category/components/fenders/ (Jan probably knows more about fenders than anyone in the cycling biz!)


Can I install a gears cassette on a regular bike?

Converting your single speed bike to geared one is probably not worth the effort, for several reasons:

Cassettes and hub gears both need different kind of wheel hubs than single speeds. You will need to change the whole wheel.
Single speed bicycles usually have narrower rear fork spacing (distance between rear fork dropouts) than geared ones. Your rear fork might not be wide enough to accommodate any geared hub.
Being single speed, your rear dropout most likely doesn't have hanger for a derailleur. Add in parts, and derailleur than can be mounted on the axle do exists, but it adds extra layer of trouble for the whole enterprise.
The frame of your bike probably doesn't have any cable guides either. You will have to either find add in guides, or use makeshift solutions.

In short, I wouldn't try it. It might not be possible at all, due to rear fork spacing. Even if it is possible, it's going to take money, special tools and quite some time put functional gears on your bike.


Can we use a 9 speed rear derailleur on a 8 speed bike?

The pull ratio, which is the important bit, is the same for nearly all Shimano 6,7,8 and 9 speed derailleurs.

Other things to look for when changing derailleurs are the capacity, minimum and maximum cog size. These will be fine for the swap you are proposing.


Why is it safer to bike with traffic, instead of facing oncoming cars?

I found this article which has some statistics on accidents involving wrong-way cycling:

  Table 4 shows that all categories of bicyclists traveling against the direction of traffic flow are at greatly increased risk for accidents—on average 3.6 times the risk of those traveling with traffic, and as high as 6.6 times for those 17 and under. This result is readily explained: because motorists normally scan for traffic traveling in the lawful direction, wrong-way traffic is easily overlooked. To give only a single example, a motorist turning right at an intersection scans to the left for approaching traffic on the new road, and cannot see or anticipate a fast-moving wrong-way bicyclist approaching from the right.


Advisable to switch from 38 mm tires to 28 mm?

Two things to take into account.
Firstly, 28mm tires lower your bottom bracket by one centimeter when compared to 38mm tires. If your bicycle was designed with 38mm tires in mind, it probably has a quite large bottom bracket drop. With 28mm tires, you can touch the ground with pedals when cornering pedaling.
Secondly, from 38mm to 28mm is quite a large change. Are you certain that 28mm tires are what you want? They require far higher pressure and the ride is less smooth.
Considering that one of the best tires, Continental Grand Prix 5000, is available as 32mm width, I would pick this width in your case. (Don't do what I do; instead, do what I say -- I use the 28mm width of GP5000 but in my opinion 32mm may be even better for people not used to narrow high pressure tires.)
The rim width may also limit your tire options. A 28mm tire requires a rim at most 622 x 19C. If the rim is 21C, you should not use 28mm tires.


Will slightly slimmer seatpost make a difference?

According to Sheldon Brown's site, there are 1987 Peugot Versailles with 23.8mm seatposts (and I have heard of other french bikes with 23.8 mm seatposts, so it is probable that you've measured correctly). The measurement should be done with calipers or a seat post measuring tool, though.

One solution I've heard of is buying a 24 mm seatpost and sanding it down until you shave off 0.1 mm. Another is starting with a smaller seatpost (bmx for ex.) and trying to shim it in somehow (coke can or whatever). Of course this is all ymmv, but its quite difficult to find 23.8 mm seatposts.

I'd probably just get the 23.4 mm one and hope for the best.


If I don't use a torque wrench, how do I tighten to the approximate torque? What can go wrong?

You can't approximate torque by feel. Loctite, grease, carbon compounds can all alter the 'feel' when you are tightening down bolts and if there was anyway to 'approximate the feel' these variables render it fairly impossible.

If you use ti/aluminum bolts, carbon components, high end aluminum do not cheap out, get the torque wrench.

If you tend towards stainless/steel bolts and less expensive components, you can forgo the torque wrench and just ensure you are working to even torque. For example, if it is a faceplate make sure that the gap between faceplate and stem is even all the way around.

Saying 'too tight is better than not enough' is not true. Too tight can create stress risers in a component (specifically I am thinking handlebar) that can lead to catastrophic failure down the road. Too tight on a square taper crankset (specifically the fixing bolt) can cause deformation of the taper fit and eventual loosening of the crank.

Hopefully that helps.

Noticed I didn't answer the question fully.

Faceplate/Bar interface
Stem/Steer interface
Crankset (whether pinchbolt or square taper style BB)

Those are areas where I would ensure proper torque. Seatpost is dependent on style of bike (ie. Madone seatMAST, or carbon post/carbon frame) as to whether torque is super important. Rotor bolts, brake mounting bolts etc... but with increasing importance as exotic materials increase.


What tolerances should I use for spoke tension when building a wheel

This blog post (google cache, original gone) on the Park site suggests a range of 20%, this thread has people saying a range of 1 on the TM-1 is fine (edited in some quotes):

I sort of try to finish within a 0.1 mm error radially/laterally and under 0.5 notch (of the tension meter) of standard deviation for all spokes.
I get DS tension under 1 notch on the park tensionmeter.
Average: 14,25 (notches of the park tension meter) Standard deviation : 0,58 notch

That's what I generally use when building a wheel. I'll look up the chart and get something like 15.5 for a 1200N tension, so I'll aim to have all spokes between 15 and 16, and most of them close to 15.5. With a TM-1 I know my repeatability on measurements is only about +-.25 anyway, so if I measure the same spoke several times I'm likely to see 15.5, 15.75, 15.5, 16... and say "buggrit, that's a bit over 15.5". But for any single measurement I could in theory chase the 15.5 target and go 1/4 turn looser or tighter, squeeze a few spokes then re-measure. But that wouldn't necessarily tell me I'd helped the situation, and might not even be accurate to within the tolerance I think I'm aiming for.
The actual process is pretty repetitive:

get the wheel fairly round, focusing more on up-down than left-right circularity (hops are hard to get out later)
run around and tightening spokes half a turn at a time to get the tension slightly under my target (say 14 using my 15-16 target)
get the wheel true to 0.5mm or so
Then I'll run the tensiometer over the whole wheel to see how even the tension is. If there's a big problem I'll back everything off a turn and try again. Otherwise I'll back off any over-tight spokes a little, tighten the loose ones and stress relieve the wheel, hoping it comes right. Then I'll re-true it. And repeat this step. Again and again, until it's all good.

Once you get the hang of it a lot of those steps will happen once at most. Normally I'll hit each spoke maybe twice with the tensiometer, and possibly a couple of spokes more than that. A good build would be tightening by feel, getting it true with a couple of tweaks, measuring and it's done. But that's very rare unless I'm on my third identical wheel in a day. If I'm fixing an existing wheel I might end up working 4-5 spokes 5 times or more trying to get it right.
One test I suggest you do is just to write down the tension of each spoke on your wheel, then put that bit of paper in a safe place. Then do it again, so you're measuring without looking at the earlier measurement. Then compare the two sets of measurements. That will give you an idea of the variability of your measurements of spoke tension. There's no point trying to get more accurate than that with a wheel, because you're chasing a random number.


Fox F120 RL fork mystery fluid - with pics

Sounds like the internal air seals are leaking. This pushes the fluid up and out the upper seals.

The F120's Air forks should be serviced every 50 hours (similar to all quality forks) , with a full service every hundred hours of riding. Its entirelyt possible its never been serviced. If the fork has not been used in a while, again, possible with a used fork, when you start to use it the seals and go suddenly.

Check the stanchions - those Fox were prone to wearing the inside of the right stanchion, just above the seal. If the stanchions are worn a repair is uneconomic, otherwise its a run of the mill fork service (Typically $US100-$US150, but pricing depends very much where in the world you live.  If you want to save money and do it yourself there is plenty of detailed information on the net.


Converting my old mountain bike to a cyclocross

Integrated drop bar shift levers are inherently expensive, so I'm not sure how much you will be able to keep the cost down.  Also, you will probably have a hard time finding 7 speed integrated levers. They would either have to be old, or low end.  And even the low end stuff is quite highly priced.  Based on the searching I've done around the web, it doesn't appear Shimano ever did 7 speed intergrated shifters above the Sora Level.  When Dura-Ace and Ultegra were in 7 speed, they were still using down tube shifters.


How much torque should a threaded headset resist?

Note that the large threaded locknut and top race on the threaded part of the headset has nothing to do with the connection with the handlebar, which uses a stem quill into the steerer tube (See the Sheldon's site for details).  You tighten up the top race/locknut only if you feel "looseness" between the handlebars/fork and the frame.

If you can move your handlebars separately from your fork, you have to tighten up your stem quill  more using that little hex bolt. Sheldon again has a wonderful diagram of the wedge bolt.

An allen key may not be giving you enough torque -- you may want to use a hex bit on a socket wrench or torque wrench. You'd have to give us the specs on the hex bolt for us to look up the appropriate amount of torque -- but it's certainly more than you could get with an allen key. But be careful of using a socket wrench as that may give you so much torque that you snap the bolt or split the steerer tube -- the use of a torque wrench is strongly recommended.

It sometimes helps if you can take the quill stem out, use alcohol to remove any residual oil off of the wedge. You can also rough up the outside of wedge a bit with a file.  Some people also use coarse grit (lapping compound) or carbon-fiber assembly paste to increase the friction and reduce galling risk.

You may want to grease the hole at the top of the stem quill where the wedge bolt enters as well as the surfaces between the quill and the wedge to reduce friction. If the bolt has a habit of loosening itself, you could use blue Loctite on the bolt threads.

But the main problem is that with BSOs, the tolerances are so poor that something is either too tight and galled into place, or so sloppy that no end of tightening will get you solid tight without breaking something else. And sometimes the drones at the factory do something truly idiotic like put a 25.4mm stem into a 26.00 steerer tube.


These mounting points are (also) meant for front panniers. By the time you get to 5kg per pannier it's the handling your have to worry about, not the load. On my tourer I've been known to strap bottle cages above my front panniers for a total of about 6-7kg per side including rack.

The weight of a large bottle of water is tiny compared to the load of a rider, and small even compared to the off-vertical loads of riding. And because the fork is designed for a small bottle the difference of adding a large bottle is negligible.

There are (or were when racing bikes were steel) very light CroMo forks; even then that sort of load wouldn't have been an issue but drilling mounting holes might have been.


should i replace the tires/tubes to sell vintage bicycle?

If it's really vintage (collectible) and has value for being vintage and the tires are original, don't change them.
When people buy vintage (collectible) thing, they want everything vintage, even if not immediately usable; if you change anything thing, it will loose value (as a collectible object)
The best thing would be for you to find good working order original tires.


According to this manufacturer's web site, some shoes can be "heat-molded":

Heat Molding
This cycling shoe is the most heat moldable shoe on the market today. Bont's resin is developed in house and has been perfected over 36 years to be an extremely stiff resin that becomes pliable at relatively low temperatures. The base of the shoe is moldable which means all stiff areas of the shoe can be molded in a standard oven. You do not need to mold your shoes if they fit you straight out of the box. To mold your shoes, remove any cleats, laces or cleat mounting screws and innersole before molding. Failure to remove the innersole can result in it becoming deformed by the heat. Pre heat the oven to 70°C/160°F. Place the shoe in the oven for 20 minutes. Higher temperatures will void your warranty and may damage your boot. Caution: Do not place your feet in the hot shoes or you may burn your feet. Let them cool a little and test the shoe temperature with your hand before placing your feet in the shoes. Tighten the straps and allow to cool. If you have any lumps or bunions on your feet or if there are any areas causing discomfort, while the shoe is hot you can use the round end of a screwdriver to press out any part of the boot. You can heat mold the shoes as many times as you like.

I read some people recommend a hair-dryer, but this suggestion of an oven seems to me more measured, a more accurate temperature.


What does this barrel adjuster do on the rear derailleur (SRAM Apex 1)?

It lengthens or shortens the housing length to adjust the lateral position of the derailleur cage. It's used to adjust derailleur 'indexing' so that the chain sits properly on the cassette sprockets.

Mountain bike shifter units have barrel adjusters, road bikes use this one as well as having frame mounted or 'in-line' adjusters some where on the housing run.

This video from park Tool Company has a good visualization of how it works:


Dura-Ace R9100 Bottom Bracket With A Dura-Ace FC-7900 Crankset?

Yes, all road Hollowtech II bottom brackets and cranks are cross-compatible.


Alternative replacement cable for classic sturmy archer 3 speed shifter?

If I was on a budget I'd go for the combination of the following two products (I'm not affiliated with this particular webshop):

Elvedes: 6451-3M - derailleur cable, €1.15
TOM adjustment nipple Sturmey Archer - adjustment nipple, €1.25

It doesn't look as nice as the original, still remains functional.

For US customers:
Cable anchor - $4.25
The cable itself still needs to be found.


Is it typical for the front and rear gear levers to be reversed?

Gear shifting has historical lineage, not always "logical" or intuitive by modern logic as observed by newcomers to the activity.

Originally, cables actuated the pulling of a mechanism, and release meant relaxing the tension, which mostly then let a spring return the mechanism to its lowest state.

This translated to pulling = lifting/pushing the system up, against the gears, so moving the chain from smaller, up onto bigger sets of cogs. Dropping = the easier task of letting the chain fall from big to smaller rings, which the internal spring could handle. When indexed shifting arrived about 30 years ago it just aligned the clicks to a particular gear; then, first in mountain bikes, then road, the integrated levers made one lever for up, the other for down.

The issue you're asking about relates to the fact that "bigger" gears up front do increase your gear, but in the rear they decrease, or lower your gear. The release of most thumb levers relaxes the cable, which drops the front to a lower gear, but drops the rear to a higher gear.

With a few unsuccessful exceptions that tried to use the spring to push the chain onto bigger sprockets, this is still the general pattern - EXCEPT Now, I understand Electronic systems can be programmed entirely different, even mixing left and right signals front to back, an exceedingly confusing idea in my opinion.

Learning to shift the traditional logic is easy enough to master in a couple weeks, so don't get worked up about something thousands have managed to cope with just fine.

Grip shifts are my preferred MTB choice, but again the tension/detension concept applies relative to which way you rotate the barrel.


How to fix a broken dura Ace shifter( body)?

Due to the critical job of your brakes in helping you race safely, the wiser action is to replace your equipment rather than try to fix this type of break.  The shifting and brake system may work now but the system is compromised and can fail at any time regardless of how you patch it up.  It's hard to swallow, for sure, but you are putting yourself and those you are racing/riding with at risk by continuing to use broken equipment.

Depending on the age of your shifters, Shimano equipment can be mixed and matched so if the price of replacement at the highest level is too much you can look into replacing with Ultegra or 105 without noticing a great dip in performance.


New freehubs are quieter, because they have a thicker layer of grease between contact surfaces in the freewheel. The grease will eventually be pushed away from the surfaces, and the hub will develop the trademark sound in few thousand kilometers.


Do I need to replace cranks after newly installed pedals torqued out along with some threads in my crank?

Your cranks are pretty much toast, and even if you try to fix them, you'll always be suspicious of them and won't be able to ride hard without worry.

Toss them in the trash and get new ones, and be more thorough when reinstalling your pedals.


How to remove completely stuck saddle post from frame

Penetrating oil (Liquid Wrench).
It may take a few days as it needs to work its way down.
Or it may free it up in a few minutes.

The risk you take with a lot of force with a pipe wrench is you bend the bike or brake off the post or get the post out of round.

You should grease the seatpost to help prevent this.  If you don't bend the post then I would reuse it.

It is most likely rust.  You cannot hammer in an over sized seatpost.

If you do sacrifice the seatpost and use a use a lot of force with a pipe wrench then don't have the pipe wrench close to the bike as you could get the post out of round and really jam it in there.  That may have happened when you got it to move a bit and then jammed.

You have a couple comments of use heat and I don't disagree but I would hit it with penetrating oil for a couple days before I resorted to heat.  Not just once.  You need to hit every few hours with oil.  If you do go heat then heat gun before torch.


What are the disadvantages of "puncture proof" (or puncture resistant) tires?

Though there no doubt are "puncture-resistant" tires that seek to accomplish that end by means of extra-thick rubber, for the past 15-20 years the standard for puncture resistance has been Kevlar belted tires, which look and ride like ordinary tires and weight essentially the same as ordinary tires (maybe a few grams more).

The Kevlar belt under the tread increases puncture resistance by at least a factor 10, eliminating most common glass/thorn punctures, and also reducing the tendency of the tire to "bruise".

Price wise, my recollection is that they are about 30% more expensive than standard tires, but they likely last that much longer (plus save a lot on tubes), so the cost is pretty much a wash.  (The odd thing is that Kevlar-belted tires are so hard to find.)

Some people apparently confuse "Kevlar belted" tires with "Kevlar bead" tires.  The latter are "folding" tires and are supposedly desired because they are a hair lighter than metal bead tires, plus they can be folded and stuffed in a pannier.  But you can buy Kevlar belted with a metal bead (my preference, since folding tires are a PITA to install), and Kevlar bead tires are not necessarily Kevlar belted (in fact, most often not).

Update:  Last Saturday I had my first puncture in maybe 5 years (maybe 2000 miles), while finishing up a 35-mile morning.  Just got around to fixing it because it's been ungodly hot and humid. (Hitched a ride home the last two miles, since there was no way to fix the flat in 95-degree weather on a 4-foot shoulder in the sun with traffic whizzing by at 70 MPH.)

The culprit was apparently a construction staple that had pierced the tire just outside the belt, gone through the sidewall of the tube, and then punched a bigger hole in the inside diameter of the tube.

I do notice the tire is wearing a bit thin, so I'll probably have to replace it within a year or so.  I'm dreading trying to find a 700/35c road tire with Kevlar belt, though -- the catalogs are now full of off-road tires and cater even less to the touring market than they did 5-10 years ago.

OK -- To make this into a direct answer to the question, the main disadvantage of Kevlar belted tires is that you forget how to change a tire, you do it so rarely.


What does "SRAM Custom" (front derailleur) mean?

If you look closely at the zoomed photo on Specialized's site, you can see that the label on the "custom" front derailleur says only "SRAM" and "2x10".  The regular ones made by SRAM say "X0" or other model names on them, e.g. here: http://www.competitivecyclist.com/sram-x0-2x10-high-direct-mount-front-derailleur-srm0437

It appears that the style of mount is readily available, but perhaps not the precise model with no labeling that Specialized is using.  Maybe that means they're using something "between" the regular SRAM grades, or maybe a different surface finish, or....  But this shouldn't matter if you simply need to buy a replacement.


Is it a good idea to sand off the rotor when exchanging disc brake pads?

Unlike car disk brakes, there is not a lot of spare "meat" on bicycle rotors. "Machining" the rotors is not really feasible. If they are worn to the point grooves are causing performance issues, the rotors should be replaced.

Sanding them down evenly (without expensive machining tools) will be next to impossible to remove scoring and maintain a uniform rotor thickness. It is likely to cause pulsating or even the brakes to grab or lock up.

A light sanding probably will not hurt, but is unlikely to make any significant difference.


If it's not broken, don't fix it. The act of folding ourselves onto a bicycle, (especially one with any kind of aerodynamic advantage over a mountain bike) is not a natural-looking position for a human body. We're built to be more or less upright, which is not an aerodynamic position on the bike.

So, if you're comfortable on your bike and feel like you're ok with the amount of wind-resistance you create for yourself, and your bike is properly sized for you, there's not much you'd really want to change.

A couple of general bike position loose guidelines (yes, general and loose are a bit redundant here, but these are not hard fast rules):

If you look down at your front hub while riding, you want it to be somewhere in the vicinity of being hidden by your handlebar.
For a commuter bike, you want to be able to look forward (with your head more or less erect) without feeling like you're craning your neck.
In said upright-head position, you shouldn't have to stretch for your handlebar.
Your seat should be at a height such that your leg is mostly extended at the bottom of the pedal stroke, but you should not have to rock your hips at all during the bottom of the pedal stroke.
Your seat should be situated fore/aft such that you can do the following:
a. Tie a weight on the end of a string.
b. Hold the non-weighted end of the string in the slight hollow on the outside front of
 your knee.
c. The string should fall close to the spindle of your pedal when that pedal is at the
 front of the stroke (3 or 9 o'clock, depending on how you look at it)

If all these things hold more or less true, and you're comfortable when you ride, don't stress what you look like.


Do belts on belt-drive bicycles stretch under load and spring back? Reputedly they don't stretch over their lifetime

Everything stretches under load.  How much is the question.

The belt manufacturers should have technical data, including stress/strain graphs, modulus numbers, or other "hard" numbers.

But, generally speaking, carbon fiber and steel both have a modulus of around 200.  It's not clear now much carbon fiber is in the belts (and the cross-section area times the modulus effectively tells you how much stretch will occur), but when you consider the thinnest parts of a steel chain, and the fact that the pins will tend to flex in tension, it's probably comparable.

In any event, stretching should not be a concern so long as it's not sufficient to cause the belt to skip on the cog, or some other mechanical issue.


Merida Matts TFS 600 original chain lube

Typically, a chain uses a grease lubricant which is applied hot to the chain into every crevase of the chain before the chain is assembled. Its generally the best lube you can get on a chain, but its impossible to apply at home in the same way (contrary to sheldon brown) [aside from the fact that that particular formula is likely not sold]. Some more details from Shimano are here.


Can I use any screw for my derailleur limiters?

I was once quoted by a retail plumbing supplier $16 per "fancy screw" for a shower fitting, and needed 6 of them.  They were M3 grub screws with a pointed end, so not large.

Instead I went to a specialist bolt-and-fastener shop and got 10 of them for $0.48 each.

So your screws have certain parameters that must be met

Length
thickness
thread pitch
thread form

And some parameters that are optional, or variable.

Head format - philips/JIS or flathead or hex head or torx, or a thumbscrew, or a bolt head....   Make sure its some tool that is in your multitool
Head width and depth - doesn't matter as long as you have enough room for it.
Material - Stainless Steel would be advisable, but other steels could be workable too.  Titanium may save a gram or so but would be expensive.  Aluminium is too weak for this application

For a B tension screw, the end that faces the frame is relatively unsupported, and should be approximately rounded off so it doesn't bear on the hanger with a sharp corner.    For Limit screws they press on steel lugs inside the mech.

Other than all that, any competent screw shop should be able to sort you out.  Only downsides are that they may be wholesalers who want to sell by the hundred or by the box/pack.   Also they may not do cash sales, so check first.


Recommended handlebar style for short daily commute?

For a short commute in street clothes I opted for flat bars with bar end extentions. This allows some different hand positions and for me a more comfortable upright position. If you are riding for the first time is several years, bike fit is more  critical than bar type. A bike that is the wrong size will never be comfortable no matter what type bar it has.


My cassette model name doesn't seem to fit the actual cassette description.. (CS-HG50-9 and CS-HG500-10)

There are usually little compatibility problems for nine or ten speed cassettes. You may choose from a large set of cassettes that work for you.

Shimano, SRAM, and Sunrace use the same standards. (The exception are Campagnolo. If there is a a cassette with a 10 teeth cog it would require a specific free hub body.)

The length of your rear derailleur's arm limits your choice of largest cog. You may check the capacity of your derailleur online. Or count the teeth on your present largest cog. Use that count as upper bound.

The lock ring of all these cassettes is interchangeable. We may never found out why yours has a different designation as the cassette. It might be as trivial a reason as a spare for a fumbled original part. Simple consequence: don't rely on it without checking.


Dual water bottle brackets on a single frame mount?

There are lots of clamp-on bottle cages (google link), letting you add bottles wherever you have space on your bike (this is just one design, and not a particularly good one IMO, better to have two clamps):

Or some clamps that let you mount conventional cages:

I suggest grabbing a couple of bottles and trying to fit them into the frame.

Also, Advantages of mounting bottle under frame has a discussion of places to get more bottles onto your frame that might give you some ideas. There are lots of clamp-on bottle cages available, so you really can just screw one on wherever there is space.

Finding a single part that will bolt onto your existing mounts is going to be hard. Putting the bottles side by side will make them too wide for you to ride comfortably, so I'm guessing you were imagining something like this?

That's a long, skinny bit of metal, that has to hold a litre or more of water... weighing a kilogramme or more. It's going to be hard to build.


I haven't been able to use the trainer very much, but it appears to work. Everything seemed to hold fine.


Will 8 speed shifters work on 6 speed cassette?

Easy answer

No, this won't work with 8 speed indexed shifters. The reason is that one click on your shifter doesn't move your derailleur enough to shift to the next cog on your 6 speed cassette.

Explanation
If we check a table of cable pulls, we see that a 6 speed Shimano cassette has a pitch of 5.5mm. Simply said, this means that the distance between 2 cogs on the cassette is 5.5mm.
An 8 speed cassette on the other hand as a pitch of 4.8mm. An 8 speed shifters will thus be indexed to move the derailleur 4.8mm on each click, 0.7mm less than you need.

Complex answer

An 8 speed shifter won't move your derailleur enough to shift to the next cog, lacking 0.7mm on each click.
Pitch however is described by the shift ratio of your derailleur and the cable pull of your shifter. For Shimano 6, 7, 8 and 9 speed, the shift ratio is 1.7 (moving the shifting cable by 1mm moves your derailleur by 1.7mm).

What you might be looking for, if you want to do some hacking are tricks to manipulate the shift ratio. On the bottom of this webpage, a number of alternative routings are described. In your case, you could try if routing #2 or #3 would work. However, fine tuning the cable pull is not very simple, and might need some trail-and-error and drilling (in case the obtained cable pull is too large).


Knees touching rib cage when riding in the drops

In an aggressively aero position, it's not uncommon for your knees to be very close to your rib cage. For example, here is the first image I found on the web of a bunch of pros in the drops. Notice the first rider in particular is just about at the top of his pedal stroke and his knee is quite close to his chest. As long as your pedal stroke is not impeded, there's no problem, although many people find it uncomfortable to ride in such a position for a long time. If your back is not as flat as his, it is possible that your bike is not long enough, which can be remedied with a longer stem.
If you do find it uncomfortable, raising the stem slightly is an easy solution. If you want to keep the aero position, but need more room to have a proper pedal stroke, shorter cranks will reduce the height of your knee. You may also want to experiment with moving your saddle forward (and probably up at the same time to compensate) so that your hip does not have to compress as far at the top of the pedal stroke.


This from an old article circa 1996 it references a Medai floor pump. "Screwed into the base near the compression tube is an air tight steel chamber. This chamber is known as a reservoir and holds a volume of the compressed air to assist in equalizing the pressure of the pumps compression chamber and the inner tube. This feature gives the tire a small assist in time as it "seats" on the rim."


Wider tires offering faster speeds and safer ride?

Depends what you mean by 'better', and under what circumstances. The major tire considerations are, in no particular order:

Drag or resistance
Comfort
Grip
Durability / puncture resistance
Mass
Aerodynamics

What constitutes a 'better' tire for you depends on your preferences and what kind of riding you want to do.

The hypothesis that GCN puts forward in a few of their videos is that narrower tire width and higher pressures do have lower rolling resistance on a smooth surface, but wider, lower pressure tires actually offer less overall drag over irregular or bumpy surfaces because they have less suspension losses.

The idea is that because wider tires don't necessarily have more drag you can run  wider tires and get better grip and comfort without a penalty.

GCN did some relatively well controlled experiments on cobbled surfaces. Here is a video that talks about what they did and the results they got:

Some more experiments on bumpy surfaces: https://janheine.wordpress.com/2016/06/14/suspension-losses-confirmed/


There are two versions of the 2400 series, 2x8 and 3x8. The 3x8 version is usually labelled as 2403, but if the amazon description says that it is 3x8, then that specific product is probably the 3x8 version. Based on the reviews and description, this appears to be the 3x8 version.


Will an 1/8' chain and cogs wear slower than 3/32' chain and cogs for single speed / fixed gear setup?

I don't remember where, but I read once that because a 3/32" chain is more flexible laterally than a 1/8" chain, it is more tolerant of imperfect chainlines.  This makes sense to me, but I haven't seen any numbers to support it.  So with an imperfect chainline you might see faster wear with 1/8".

I suspect the difference in wear is imperceptible, especially with a steel cog.  The combination of a 1/8" chain, imperfect chainline, and an aluminum 3/32" cog would probably be where you'd see the most increase in wear because you add a slight bit of play where the chain interfaces with the cog, but I still doubt you'd notice much additional wear.


Without tubeless ready rims it will be hard to get a traditional tubeless setup to work.

What could possibly work might be a ghetto tubeless setup as described here:
http://www.mtbtechniques.co.uk/MaintananceGhetto.html

Altough this is specific for mountainbikes. On a road bike I would suggest getting proper rims for a tubeless setup.


The problem here is that with a carbon or aluminum frame it will be hard to assess the damage accurately (at least with the tools that we or a LBS is likely to have). The best tool that you've got is evidence of stress on the frame – like the cracked paint in the photos of bike 1.

Add to this the likelihood that aluminum or carbon will fail dramatically and suddenly if they are damaged and it just seems prudent to replace the frame.


What percentage of bike vs. car accidents at night could be avoided by good side visibility?

Summary: very few. Somewhere between 20% and 90% of crashes involve a motor vehicle approaching a cyclist side-on (guess ~50%), and somewhere between 30% and 90% occur during darkness (guess ~50%). Unfortunately 40% or more are the result of drug-impaired driving or riding. So perhaps 60% of that 50% of 50% = 15% could be avoided if the cyclist had bright side lighting.

The wide ranges are a result of small numbers and inconsistent statistics collection. As with anything that is quite variable and happens infrequently, random variation makes it difficult to see trends.

First, modern usage is to talk about "crashes" or "incidents", partly because that allows us to talk about who was at fault.  99% of crashes are caused by people who intended to do what they did but failed to do so safely.

New Zealand publishes something close to what you seem to be after: Cyclist-Crash-facts-2012.1.pdf (pdf link) that includes this summary:

BicycleUniverse has a useful summary with references:

  Cyclist fatalities occurred more frequently in urban areas (66%), at nonintersection locations (67%), between the hours of 5 p.m. and 9 p.m. (30%), and during the months of June, July, and August (36%). (NHTSA, 2004)

Although they list a number of conflicting statistics on intersection fatalities (also 89% and 33%).

It's rare to find that type of incident breakdown in published statistics. This page from the USA, for example, doesn't even separate fatal from non-fatal accidents when attributing fault. And they talk about cyclists breaking the law but not motorists, so (for example) if a cyclist did not have a rear reflector on their bike when a motorist T-boned them the statistics would say "cyclist breaking the law, hit by car". This is regrettably common across all analyses.

  More than 15 percent (16.6% and 60 crashes) occurred when motorists
  made careless turns. Data showed that cars are four times more likely
  to sideswipe a bicycle than vice versa.

The key points there are:

  Nearly 75 percent of bikers were killed between 4 a.m. and 8 p.m. Nearly 20 percent were killed between the hours of 8 p.m. and midnight.
  Alcohol-impaired riding or driving was reported in more than 40 percent of the accidents that resulted in bicyclist fatalities in 2009. In a third of the crashes, either the driver or biker had a Blood Alcohol Content (BAC) level of .08 or higher (the legal limit).
  Bicycle rider fatalities occurred more frequently in urban areas (69%), at non-intersection locations (64%), and between 5 and 9 at night (28%).

The first point is near-meaningless (75% of cyclists were killed during 66% of the day). But 64% not at intersections suggests that side visibility is not likely to be a major issue (at most 36% of fatalities).

There's a big collection of links to papers at the Cycling Resource Centre (Australian site, worldwide links).

Examples:

  Vehicle drivers undertaking a turning manoeuvre posed the biggest threat to cyclists who were generally travelling straight on a carriageway. Those drivers undertaking a right turn manoeuvre posed the greatest threat, particularly those turning across multiple traffic lanes and in peak hour traffic conditions. Young drivers were seen as the group of drivers most likely to be involved in these types of crashes.

There is an excellent, although complex, chart on page 27 of "Road Traffic Crashes in NSW 2011 (Australia)" (pdf link) but it covers all road users and does not break out cyclsis. I suspect what you're looking for is something like this that only covers cyclist incidents.

For non-fatal accidents, BicyclingLife compares three cities (with references) and concludes that motorists failing to give way at stop signs in the most common cause of crashes.


Tips for cycling while pregnant, and is it safe?

This would have to be

one of the most opinion-based questions we could possibly have, and
one of the most important to deal with in a sensible manner.

Firstly, it must be said that what is safe depends on the woman's own behavioral history, and the state of the pregnancy. She certainly should not be taking up new active sports.

Some competitive sports ban obviously pregnant women from participating, not through any risk to the woman or child, but because she has two advantages. She has a greater blood supply, and competitors are likely to "go easy". I recall this was the case when I played competitive squash.

The mother of my children cycled (on a road bike) until month seven in both pregnancies. With her extra blood supply, she would leave me behind on the hills! She only stopped when her belly was hitting the top bar. It should be said that both pregnancies were completely normal. She did discuss cycling with her Ob, who agreed that since she was already a cyclist, she could continue, but that she should be sensible and stop if problems developed. She cycled about 60km (38 mi) in 3 or so rides per week.

She did find her balance changed. By doing the activity continuously, she adapted to that.

My recommendations are

Listen to the obstetrician. You chose this person for their guidance, for a reason.
Only cycle if already a regular, confident cyclist.
Always ride in familiar, safe places, and with a buddy.
Ignore those who use emotional blackmail in their arguments. This is an emotive topic; it needs clear factual arguments to form a balanced decision.
Every activity involves risk, including no activity, and being wrapped in cotton wool.

Enjoy!

PS The great Sheldon Brown's alter ego Carapace Completed Umber also wrote about Riding while pregnant.


Your rear hub would have been manufactured by someone other than Schwinn. Given the age it was probably manufactured by Sturmey-Archer or Sachs (now SRAM). Those links contain links to small parts for both hub brands.

Sheldon writes:

  The axle threading of most SRAM internal-gear hubs is unusual, 10.5mm x 26 TPI, but close enough to that of many Sturmey-Archer hubs (13/32 x 26 TPI) that Sturmey-Archer axle nuts are usable in a pinch.


How to identify a MTB for heavier riders?

Answer: Its all about risk (for you) and liability (for the maker/seller)
A bike rated at for a X kilos will not suddenly fail at X+1 kilos.  However beyond this point, the likelihood of load spikes increases, so the whole bike suffers and deteriorates faster even if you only ever ride in steady state. This might be known as the "knee/elbow" of a graph.
Naturally manufacturers/importers want to minimise failures where they have extra costs, so a weight limit helps them.   This is similar to saying "this bicycle is not for stunt riding".
The risk to you is, what happens if a part fails catastrophically while you're riding?  If you're going slow vs a medium or even a high speed failure?
A simple fall for a heavier person is on average more damaging than the same fall for a lighter person.  Add some forward motion, and the momentum can make a minor graze into a more significant cheese-grater, and depending how you land can transform a bruise into a break.  These are the risks.
Minimising risk   To do so, look for a bike with certain features

Higher-spoke count wheels.  There's a trend to reduce the number of spokes and call it aero and weight saving.  But ideally your wheels would have a minimum of 32 spokes on the front and 36 spokes on the rear.  If possible, 40 or even 48 spokes on the rear would be even stronger, but will cost/weigh more.
Metal frame.  Anything that can be described as having a "sudden spontaneous failure" should be avoided, so that rules out Carbon Fibre as a frame material for your bike.
This leaves Steel or Aluminium as your primary options, with exotics like Titanium as rare possibilities.   Steel would be ideal for your needs because it is relatively elastic, and its failure modes tend to be quite gradual.  A steel frame will bend or tear, but generally will not part completely.  Aluminium would be another common possibility, but suffers from "work hardening" so as an AL frame is stressed and relaxed, it will slowly get harder and more brittle.  That said, it takes decades to "wear out" any aluminium frame so if you're going new, then this isn't an immediate issue.  If you're going second-hand, have a very good look over the whole frame before committing, looking for dents and cracks.
Diameters - In the old days a 25.4mm (1") seatpost was enough for everyone.  Now there are more sizes, and strength goes up as diameter increases.  So look for oversized seatpost of 31.6mm, and handlebars of 31.8mm.
Tyres - you're talking about mostly road, sealed paths, maintained gravel paths, and not-hard trails.   Realistically, these are not challenging surfaces for a tyre.  Aim for 50-63mm (2"~2.5") tyre widths, and look for smoother tyres without aggressive knobs.  A slick tyre would be fine for road usage and would be less effort to ride, while probably being adequate for any pathway.
Suspension - possibly contentious, but IMO you don't need any suspension on the road at all.  It tends to add weight and compromise the bike, and the returns aren't worth it.  This also includes suspension seatposts and suspension stems.  Same goes for simple paths which are really just roads for feet.  The only time suspension might help you is if you're going fast and don't take a good line, ending up somewhere bumpy and going too slow, resulting in a fall.
Upshot - if you can ride the path without your tyres leaving the ground then suspension isn't really needed.
If you DO choose suspension, make sure its rated for your weight, which is not the same as any limits on your frame.  For air suspension you'll need an air-shock pump to add air when setting the sag.  For coil sprung suspension you'll probably want the bike shop to help set it up for you with the right number/grade of inserts.  For this reason, a tuneable air-suspension would be better than a coil-based suspension.
Pedals - decent quality flat pedals are all you'll need.  Avoid clipless/cleats at this point, save that for the next bike.   Flat pedals also help you get a foot down quicker should that be needed.
Saddle - avoid big wide squishy padded saddles - they may look comfortable but they tend to not be.  Instead search here for "saddle width" questions.
Position - Aim for a bike that lets you ride with a more upright-position.  I found that my gut was in the way on a road bike to start with.

Another option for you is to look at a tricycle or trike.  They have an extra rear wheel and will carry more weight than a two-wheeled bike. Downsides are they're wider, and tend to cost more due to rarity.  Overall stability is lower too because they always conform to the slope of the ground, but on flat land its impossible to fall off.  They tend to appeal to the elderly who may have balance issues, so resell value is generally okay.
Speaking of resale value, a well-specced "heavy rider" bike should hold its value and in a couple of years can be sold off once you no longer need it.
"Fat bikes" are called that because of the width of their tyres, not because of the rider.  So don't assume that having big wide tyres means a bike will work for your starting weight.
You can chart your weight over time - I log my weight first thing in the morning, and additionally after significant exercise which reinforces how much good each ride is doing.   I ride mostly to commute, which means I have to ride whether I feel like it or not.
Upshot - yes I would observe the weight limits of manufacturers, but consider it motivation.


Rubber on wall mounted bike hooks is wearing away. What can I use to cover them so my wheels don't get scratched?

@rclocher3's electrical tape is the easier way to go, but I often use strips of old tube to wrap things of this nature.  To keep the wrap in place I dab some vulcanizing fluid hither and thither along the underside.  This saves electrical tape for electrical things, is perhaps a bit more rugged than tape, and also provides fodder for people who would mock me on stackexchange.


Expanding on my comment cos a picture is worth many words - this is the line which is the bearing surface, that the ball bearings "bear" onto.

The slightly bronze circle that is closer to the hole in the middle is important as it provides support for the critical area, but the shape doesn't really matter.  Yes the inside edge looks slightly deformed, but since its not the track on which the balls roll, then its not important.

Here's a modified cutaway from figure 6

If you want to put this to the test, clean your parts and the old balls and then draw on the bearing race with whiteboard/dry-erase marker.  A sharpie might work.  Either way, avoid black.  Reassemble your bearing completely dry of grease and spin it by hand for a couple revolutions to put witness marks into the dry marker-pen.  Only need to do one side of the axle, not both cos its only a test and not for riding.  Use the old balls so you don't scuff up new ones.

I think we were talking about different silver circles in comments.

The other possibility is that there is some artefact you can see directly that isn't showing in the photos. Damage like on this spalled cone may not be visible in the photo, which would be completely different.


Anti-rotation washers (non-turn) washers in non-parallel dropouts?

The torque that the axle sees relative to the frame can happen in both directions as gears change.

For example in the classic Sturmey Archer 3 speed, it's the second gear that is neutral and does not place a torque on the axle.  In third gear the axle will try to twist forwards, and in first gear it will try to twist backwards.

For this reason you really do need an anti-torque washer and you can't leave the gap in the second picture above or below.

I would try to use a normal anti-torque washer against the inside face of the dropout.  This washer will have the square hole to grip the axle.  Then I would try to make a second washer-wedge-combo out of a softer metal (e.g. Al) to go on the outside.  The wedge part of this piece would fill that gap between the red lines in the second picture, but it's strictly functioning as a wedge and can have a round center hole.


Can a 7 speed Derailleur work on a 8 speed cassette

8 speed shifter and cassette, 7 speed derailleur? You'll be fine. There's no "probably" about it.

6-, 7- and 8-speed gear is all cross-compatible in terms of chain width.

The only time you'd hit a problem is if the shifter and the cassette weren't made for the same number of gears, for example you could imagine a scenario (e.g. 7-speed cassette, 8-speed shifter) where you might click past the edge of the cassette. That would negatively impact your day.


It doesn't matter what it's made out of, bike stuff gets stinky. Especially the stuff that goes on your hands and your feet since they're similar appendages that you keep similarly wrapped up and pressed against surfaces that don't breathe well.

There are a lot of active wear specific detergents out there- Sportwash, Sport Suds, WIN, Nikwax, etc etc. I've tried none of them, but probably should. Most of these detergents are supposed to be especially well suited at removing odors from synthetics. I see a lot of folks recommending castile soap or oil soap for leathers. This is usually for larger pieces like jackets and handbags. Given your situation, I think you're probably overthinking it. A soak in warm soapy water using a bar soap that you'd use in the shower followed by a brisk hand scrub and rinse should be sufficient. Air dry them, and if you're really worried, use a light leather conditioner once they've dried.

They're going to get stinky again, and quickly. There's just no way around that. Your hands are just funny looking feet at the end of your wrists that you're pulling these leather socks over and perspiring heavily into. Wash them as necessary with mild detergents and realize that- just as with almost everything else you purchase for the sport of cycling- the gloves are consumables and they won't last forever.


Is there such a thing as 'eBike specific' freewheel?

I agree with you that a hub drive e-bike should not impose any more stress on a freewheel than a conventional bike.  Whichever wheel you drive, the torque supplied by the motor is not going through the freewheel.  The torque transmitted by the freewheel is all generated by you, just as on a conventional bike.  A stretch would be to claim that you can generate lots of torque in short intervals, then let the motor drive you in between, while on a conventional bike you would have to be working all the time so the torque peaks would be lower.


For the ultimate in pizza carrying, you want a pneumatic air suspension, pendulum-based anti-sway bar equipped carrier. This are/were used by ramen delivery bicylists in Japan, although they are getting rarer (people don't order delivery ramen noodles like they used to) and mostly on motorcycles now:

With one of these babies, your pizza (or ramen) will not sway from side to side, bump around, and end up all mashed into one big congealed mess.

Of course, it costs around $400 and you can only get it in Japan. But if you're serious about your pizza carrying, it's the only way to go.