Chain keeps skipping - did I cut it too short? My old chain was skipping a lot, so I replaced it with a new one. The new chain barely skips at all, except for in the highest gears/smallest three cogs on the back cassette. The skipping comes progressively often as the gear increases.
The cassette does not look worn out. The rear derailleur seems to be indexed correctly but curls up very tight in highest gears.
I cut the new chain to be the same length as the old. In order to do this I only had to remove one link in the chain, which makes me wonder if the previous chain was cut too short (or too long).

The cassette does not look worn out

A cassette that is worn does not look worn.
It'll skip anyway despite not looking worn.
I suspect your cassette is simply too worn.
(Interestingly, for chainrings the opposite is true: a chainring can look very visibly worn due to the non-even wearing at different crank orientations, and still work.)

The new chain barely skips at all, except for in the highest gears/smallest three cogs on the back cassette. The skipping comes progressively often as the gear increases.

This is exactly the symptoms of a worn out cassette. The skipping happens at the smallest sprockets. The smaller the sprocket is, the more likely it's to skip.
The skipping always happens when putting a new chain. With the old worn out chain, it won't skip unless it's practically destroyed as the cassette wear matches the chain wear. After a new chain is put in, the wears no longer match and thus the skipping starts.


Very stiff front derailleur My girlfriend has been having problems with her front shifter/derailleur since she got her bike. For some reason, moving the chain from the middle ring to the big ring at the front, is very stiff.

Her left shifter is an ST-EF50-7 (triple) like the one in this picture  and the front derailleur is a Shimano Tourney TX51 (top pull)

This is the cable routing to the front derailleur.

Her bike has been used just a few times, and I have inspected the cables and moving parts and everything seems to be ok. No rust, cables have been lubed just in case, etc. Front derailleur is properly adjusted (both low and high screws are set up properly). As long as you push the lever really hard, then everything shifts properly. Something that I have noticed is that in order to shift into a bigger gear, the shift lever has to be pushed quite a bit before it "clicks" and stays in the next gear.

When the cable to the derailleur is not attached to anything, the shifter lever moves smoothly, so I believe that the shifter is fine. It appears that just for some reason, the front derailleur has a very stiff spring that puts up too much resistance. Can anyone recommend me what to do? I'm believing that changing the front mech may be necessary in order to get it working properly.

First of all, if the bike is new and there is a problem with it, just take it back to the store where it was bought and ask them to fix it. Most bike stores in the US offer some sort of tune up after a few weeks to deal with any problems that crop up, re-adjust as cables stretch etc.

If you need to diagnose and fix it yourself:

You have ruled out the shifter, so the resistance must be in the cable or the derailleur itself. I doubt it's the derailleur spring being too stiff. The derailleur lever mechanism and springs are designed to have approximately constant  return force across the range of movement. The inexpensive Tourney line is has some stamped sheet metal parts, there may be a burr or defect that is preventing the derailleur from moving freely.

To check the cable, disconnect from the derailleur at the pinch bolt. While holding it taught at the end work the shifter and make sure the cable moves freely and is not hanging up at all.

With the cable still disconnected, you can manually push the derailleur cage from the small ring to large ring position to see if there is any resistance. It helps of you can pop the chain out of the cage, there should be a small screw that you can undo to open the cage and slide the chain out.


Freewheel is not making noises Freewheel on my bike is not making any clicking sounds like it used to when I bought the bike from the bike shop.

I got the bike serviced last month due to brake making screeching noises and the rear wheel is wobbling.
I don't know what the bicycle mechanics did to the rear wheel except that he filed the brake pads clean.
I m guessing that they added more grease or sprayed some degreaser on the bearing wheels in the hub and did some adjustments to the rear wheel.

Based on your symptom of the 'rear wheel being versatile" which I take to mean a wobble related to loose bearing adjustment in the hub. If the mechanic completed a complete hub overhaul the axel, bearings and cone nuts would've been removed, examined, replaced if needed and then put back together packed with new grease and adjusted properly so that the wobble was gone.  None of this takes place where the "clicking" is generated. However I often try to get some lubrication dripped into the freehub where the pawls engage to create the drive force of the sprocket. A combination of lubricant and a tighter bearing system can sometimes quiet the pawls. Other times the sound is more distinct as the liquid lubricant loosens the old grease and the pawls move more freely and "snap" through their range of motion.  Obviously there may be something wrong if you're experiencing a slipping sensation or if when you begin pedalling again after coasting there's a sensation of the cranks free spinning and a delay in the normal resistance to pedalling.


What is the minimum tire width for a 18 mm disc rim? I have a Croix de Fer cross bike that I purchased for touring with luggage; for commuting to work, lighter touring and some mild offroad riding.

While it is nowhere stated officially, I can see on this review that the rims are 18mm wide:

What range of tire width can I run? Saint Sheldon says 25-37mm for 17mm and 28-44mm for 19mm. And that it is on the safer side. What can I ride on this rim?

Also, the fact that the rims are for disc brakes and their lack of brake track makes them a tad shallower. Does that change anything to this consideration?

I think Sheldon's recommendations are a good rule of thumb - I might be wiling to go a tad narrower if I were truly compelled to do so, but that's all to be taken with a grain of salt. In terms of rim depth, it should play no part in your tire choice whatsoever as it has no bearing on how the tire will seat into the rim.


Rear wheel wobbles with periodic sound My road bike currently has a nagging wobble in its rear wheel that I've been unable to determine the source of. I probably would not have noticed this had it not been for an unusual (and annoying) sound that appears when the wheel rotates.

The sound is hard to describe, but I'd have to say it has to sound like a low-pitch popping noise - quick, with sudden boundaries. It appears probably every 5 or 10 degrees of rotation and causes noticeable vibration in the frame. It is also worth noting that this is not an issue that gradually built up over time - it appeared after the last ride, so it is almost as if something wasn't squared properly when I reassembled the bike afterwards.

In attempting to find the source of this, I checked to see if the wheel was rubbing up against the brake caliper or if the magnet was making contact with the speed/cadence sensor - both negative. The lateral deviation of the wheel is really too small to be of concern (other than the sound), and the noise seems to be coming from the rear axle/freehub area.

What I most fear is that the wheel may be out of true - the bike, around its last ride, took a few not-so-nice rides to a local park in the trunk of my compact car. While none of the suggested questions really seem to be describing my issue, it seems like a common culprit of rear hub noises is the cone parts.

Given all that, I suppose my question is twofold:

Is there a way to either confirm or rule out the wheel true as the source of this issue?
If it is not the wheel true, what is this problem likely to be caused by and how do I go about fixing it?

If you are getting multiple clicks per revolution wheel trueness (relating to even spoke tension) is not the issue here.  A bumpy ride in a car will not damage a wheel - spoked bicycle wheels are actually pretty strong.

Wheel trueness is easy to check though. With wheel held off the ground spin the wheel and watch the rim relative to a convenient point such as the brake caliper pads. If you have disc brakes s piece of tape or a zip tie on a chain stay works well. Some wheels will have a little lateral or radial deviation, but if the rim isn’t hitting anything it’s not causing this problem.

A loose spoke would create a click once per wheel revolution so that’s not the problem either.

I strongly suspect you have a problem with a bearing. Hold the wheel off the ground, grab the tire/rim and rotate the wheel. If you feel resistance, grinding or 'notchiness' there is a problem. Also try to push the rim back and forth laterally, there should not be any lateral movement or play. You can also take the wheel out and turn the axle by hand to feel for resistance, grinding, notchiness, or play

Next step is to determine what kind of hub you have and how to disassemble it to find out what broke.


I was in a collision the other day. What should I check? I was making a left hand turn the other day when a u-turning vehicle t-boned me.

I somehow managed to land on my feet, but the bike didn't fare as well. It landed on the drive side.

My back wheel was tacoed, and the driver bought me a replacement.

Now that I've had some time to install the replacement, I'm noticing that either my derailleur or the hanger is bent. It looks like it's the hanger, but is there a way to tell?

What else should I check? I've cleaned up the frame looking for cracks and it all looks good. It's a pretty robust aluminum frame, so I'm not surprised. Is there anything else that may be wrong?

I'd recommend not taking a chance you'll miss something and take it by your local bike shop. They have a tool that can correctly re-align a bent hanger...this is much more likely then the derailleur being bent. Also, the mechanics have looked at tons of bikes up close and will notice little things that you might miss. Many LBSs will do a post crash check for free (the one I hang out at will).

That said, here's what I check when someone brings me a crash bike.

Good look over of the bike in it's current state before I begin. I'm looking for signs of how the bike hit, scratches and the like. If I wasn't the rider, ask the rider how the accident happened. This will help me to focus more intently on some areas. Don't let this make you focus to the detriment of the rest of the bike. Before doing anything to a bike that may have legal/insurance claims make sure you document with photos...if appropriate get clearance from police/lawyer to start having the bike put back together.

Frame soundness. With the wheels off, carefully go over the frame and fork for any cracks, dents, bends, or scratches. Scratches are okay, but they can help pinpoint impact areas. Wavy paint can show where a frame is subtly bent. A tiny crack on the surface may be deeper/bigger under the finish. Most of the time we think of cracks in conjunction with carbon, but a aluminum (or even CroMo) frame can get stress cracks as well due to a collision. With metal bikes, bends and dents can weaken the integrity of the frame as much as a crack does a carbon bike. The bigger the dent or the closer it is to a weld, the worse.

On metal bikes, look at each weld carefully. A bad weld can hold for years and then separate due to stress. I haven't seen this on a bike frame, but I've seen it on other equipment.

Steer tube/headset - is it still straight. Often the handlebars will be pushed off straight with the tire. This can be fixed quickly (loosen stem, realign, tighten stem), but is another indicator of stress. If not straight, spend some extra time here. Either way, check that everything moves as smoothly as it did before. The angle/alignment/tolerances within the headset are small and a little bit of being off can cause binding. Loosening the compression nut (top of steertube) and re-tightening can often realign. If you haven't worked on a headset before, get a hand from your LBS to show you torque and order.

Brakes - quick and easy, are they damaged? Do they still work? Scratches are okay as long as the scratch isn't rubbing anything.

Drive train - the hanger (as yours probably is) is often the first casualty. Remove rear derailleur and check (LBS has the special tool). Next look to see if there's any damage (other then cosmetic scratches) on the RD, especially where the shifting cable is routed and tightened. Move up to the front derailleur. This can be bent pretty easily. Usually it can be bent back, be careful though...easiest to have a bike mechanic bend it back into shape if needed. Check the chainrings for missing teeth (note that on some cranks, there are supposed to be missing teeth to aid in shifting) or bends. Check that the bottom bracket is still tight and that the cranks rotate smoothly with no binding. Check the chain, ideally remove it and let it hang - that's the easiest way to see single link bends, it should hang straight...if you leave it on the bike, slowly rotate the cranks while watching the middle of the chain from above, you are looking for any bend - it will present as an angle between two links.

Seatpost and saddle. Saddle may have been turned, but even if not, I recommend completely removing the seatpost (mark the height for reassembly) so you can look for bends or cracks. If bent it won't come out/go in smoothly. If cracked, you need to get a new one and do a careful inspection of the seat tube.

Wheels - check for cracks in the rim, cracked nipples, bent or loose spokes. Take off the rubber and put on a truing stand checking for true, dish, and roundness. Check the rubber for skid wear and/or gashes.

Rider - keep aware of yourself for the next several days. You can miss that you also hurt something else because it doesn't start really bothering you for a bit. My last crash, my shoulder felt fine for a day then started bothering me...it was minor, but if I wasn't paying attention I wouldn't have connected where/how the injury occurred which can be important to the doc if you end up needing medical intervention.


Should I sell a custom built mountain bike as a full bike or break it into parts? I have a bike that I have built up over the last few years. It's a good bike and works as it is, with a good quality components. However, I want to sell it. Is it best to sell it broken down as parts or as a full bike?

It may depend on the overall age of the bike but I would guess that in most cases it's better to sell it as a whole. If the bike only consists of rather standard components that one could easily buy at a LBS, then they wouldn't make high prices and the additional work to break it all down and maybe set them all on on ebay separately may not be worth the money.

I can imagine only two cases where it may be better to sell it in parts or at least to sell some parts separately:

You have one or more high priced components on it that are still nearly new and unused, or
there are some (older) components that are no longer available from the manufacturers but make a high price even when bought second hand as they are required to repair an otherwise still working bike (imagine 7-speed shifters from the former higher priced component groups such as Shimano XT to replace a damaged one).


Help with replacement tire and tube for little girls bike Good Morning,

My 4 yr old received an old bike from one of the neighbors today, unfortunately both tires are flat and cracked and there may be damage to the inner tubes as well.

I am not able to go to a bicycle store to have them replaced. So i figured I would try and replace both myself, as I found some DIY youtube videos on how to do the process.

The challenge I am facing now is finding the correct parts to do it.

On the tire itself it says a size of 18 x 1.95, I was able to find a tire for this size on Amazon (Amazon Link). The original tires on my daughters bike look different though, a little research told me the original tires are mountain bike tires, by the looks of it. But my daughter will only be riding her bike on the road/side walks so I am assuming this tire I found on Amazon will be sufficient.

Now I am trying to find a tube for this tire, but cannot find a tube with a 18 x 1.95 size. I am even thinking that maybe I am looking for the wrong size tube for this tire size.

I have never changed a bike tire nor a tube in my life and would appreciate any assistance in locating a compatible tube for this tire.

Also if someone could tell me if this type of tire that I found on Amazon is suitable for the road/side walks.

Appreciate any help I can get.

Kind Regards,
Andrea

For a four-year old, who will be riding around your backyard or at the park, any tire that holds air will be fine.  There's no MTB-specific tyres that small.

Those tires will be totally fine on pavement and will work well enough on dry grass too.

The tyre specs in your link are for an 18" tyre (that's the measurement across the whole wheel) which is 1.95" in width, which is the horizontal width of the tread approximately.

  18" is unusual - is it possible that it reads  16" ?

Most tires have a ETRTO code - I suspect your current tyres will say something like 47-305 on the sidewall (or possibly 305-47 which is the same thing just reversed.) It means 47mm wide tyre, and 305mm across.

The bigger number has to match your replacement tyre, but the width has some leeway.

Could you please check your old tyres for the ETRTO code, and once you have that,  the replacement must match.   Your Amazon link doesn't show a ETRTO code sadly, but there will be many others that do.

Your other option is to simply inflate the existing tyres and see if they hold air.  Depends if they're just faded, or rotted to useless.   If there are bits of rubber falling off, they're definitely in need of replacement.

As for inner tubes, the ones on your bike now may be okay even if the tyres are rotted.  You will need to add some air and see if they hold overnight.

If you do choose to buy tubes as well, there are similar numbers to match in terms of size, but the tolerances are larger.

You'll need to get two tubes of course, but the box will cover a larger range of possible sizes.  See the front of this one which covers 340,349 and 355 sizes with the same tube.

Lastly you need to have the same type of valve as the old tubes - its 99% likely you will need a Schrader valve, same as on a car tyre.


How to DIY electric bike modification - Schwinn 3-Wheel? I've come across a mint condition 3 wheel Schwinn bike (big tricycle) and I'd like to modify it to be electric driven. My main focus is an efficient electric system and I would like to integrate solar charging at one point.

I'm willing and able to build it myself. I don't need a kit although I'm interested in integrating the most technical advancement within the last few years.

Recently, I spent some time in California and it appears the best and fastest electric bikes have the motor mounted in the front hub to pull the bike. This Schwinn bike has a very large basket behind the seat mounted over the rear axle where I could have larger battery packs.

How can one modify this 3-wheel Schwinn to an electric bike?

Note: It will be used only on relatively flat terrain, in Florida.

Delta tricycles (trikes in which the two paired wheels are in the back) should either use:

A crank-based motor such as a Bafang BBS-HD (these are usually called 'mid-drive' but this designation makes less sense for recumbent trikes). This would take advantage of the rear differential (if available). If the trike doesn't have a differential, it will pull in the same direction as when pedaled. With a powerful crank motor, this can be quite dangerous as it will either you pull you into traffic (left) or off the road (right). So I would suggest you use mid-drive crank motor on a trike only if you have a differential.
A front hub-motor is better given the complexities of creating a differential for the two rear wheels. This has the advantage of not pulling to one side, but the disadvantage that you can easily lose traction, especially when going uphill (and especially if you have your batteries in the rear rack).

However, beyond this pithy answer, the actual complexities of installation are up to you and the particular motor/kit you choose. We're not a shopping site so asking "What's the best hub motor for a trike" would be ruled off-topic. You should instead ask "What characteristics of a hub motor would I look for if trying to install one in my trike" or "Which wheel should I put the hub motor in on my trike?" or "Should I use a throttle or pedelec for my trike electrification."

Finally, remember you can also always ask specific followup questions ("how would I install a Bafang BBS-HD given my recumbent's raised crank") once you've made the decision.


Does a chain ever need to be loosened by bending sideways with Shimano reinforced pins? Today, I installed a new chain to my bike, because it was badly in need of lubricant (squeaking) but Shimano TL-CN41 showed it is worn so I decided to install a new chain instead of lubricating the old. Hanging the chains side by side, the old 116 link chain was 9mm longer than the new 116 link chain (0.6% wear). The new chain is a 8-speed Shimano HG71. It was shipped with a reinforced connecting pin.
I pushed the reinforced connecting pin in with a chain tool. After the pin was fully in, the pointed side being fully protruded from the other side, I expected the chain might need some sideways bending to make it slightly looser.
I was surprised to find that the chain needed no such sideways bending. The link pushed by the Shimano reinforced connecting pin was already loose enough, definitely not a stiff link.
Is this some kind of design feature of the Shimano reinforced connecting pin that always results in no stiff links? Or is it possible that sometimes the chain has a stiff link after installation, and the chain needs to be loosened by bending sideways? I remember that before the days of Shimano reinforced pins, the chain often (always?) needed sideways bending.
In the end, I snapped the protruding end away with a 4" adjustable wrench, and am planning to check whether it needs a new cassette too after it stops raining.

I've certainly had a stiff link at the join on my 8-speed hybrid. I usually use IG51 on that, but have used HG71 so I can't remember which one gave the stiff link. Since using master link chains on my newer bikes I've started to prefer them, but could only get HG53 recently, with a special pin. That didn't stick, but like you I was half expecting it to.


Why are electric bikes ranked on torque ratings? A major ranking criterion for electric bikes is the torque rating of the motor.
Generally speaking, bikes/motors with higher torques are sold at a higher price than bikes/motors with lower torques.
As a follow-up of this thread, I get that having a bigger torque helps in torque intensive situations, like hill climbing.
However torque can easily be multiplied/demultiplied using gears between the wheel axis and the motor axis. For example, these gears can be dedicated (embedded in the motor itself) or in the transmission system of the bike.
So the torque that matters is the final torque on the wheel axis, not the torque output on the motor axis.
So, this implies two questions:

Use of dedicated gears to change output torque: Why is torque rating sold as a discriminatory constant of the  bike (especially for the price), where it's easy to just add a gear on the motor itself to increase the torque, at the cost of increased RPMs of the motor axis (as it's done on electric cars)?
Effect of the transmission system on the motor torque: Since motors can be hub motors or mid-drive motors, the motor is not at the same transmission step: meaning the same motor output torque will not have the same impact on the wheel torque.
For example, a hub motor with a torque of 50 Nm will provide a final torque of 50 Nm to the wheel. However, a mid-drive motor with a torque of 50 Nm, with a gear ratio of 0.5, will provide a final torque of 25 Nm to the wheels.
With this in mind, how to interpret the advertised torque for a bike with a mid-drive hub, since it's heavily dependant on the transmission?

Addressing just the actual question as stated to avoid a 3,000 word essay:

With this in mind, how to interpret the advertised torque for a bike with a mid-drive hub, since it's heavily dependant on the transmission?

The advertised torque on a mid-drive bike will tell you over how large a band of cadences and how steep a hill the bike can actually provide the advertised assist level in watts.  (generally 250W equivalent mechanical rider input at the crank.)
A low torque bosch active line motor might only provide 250W of equivalent mechanical input assistance at exactly 70rpm on flat ground, whereas a Performance CX can provide that assist level at much lower cadences and on much steeper inclines.  The manufacturers try to reduce this to a simple number because it's consumer marketing.  (and also the drive system manufacturers don't sell you a final assembled bike, so they don't know what final numbers will be at the drive wheel in the installed system.)
The marketing is targeted to consumers buying finished bicycles made out of mass market bicycle parts.  In reality the transmission is always going to go from a bit over 1:1 to around 36:11 to 38:11 and the drive wheel will always be about 26" to 29" outer diameter, these things aren't just infinitely variable to get whatever outcome you want.
Certainly if it were all made out of infinitely ideal "high school physics" components you could use any combination of motors and gearings to get any torque number you like, but these things have to be made out of real materials that don't strip teeth or snap in half or overheat when spinning at the speeds that people's legs actually turn, so there are a lot of engineering compromises to be made.


Are road caliper brakes usually compatible with any model of lever/STI shifter? I have a Specialized Allez 16 (2011) road bike with Shimano 2300 STI shifters and no-name brand caliper brakes. The brakes have always felt a bit mushy despite my best efforts at adjustment/replacing pads, so I'm thinking of upgrading them, perhaps to Shimano 105s.

I am under the impression that more or less any model of road caliper brakes can be used with any kind of brake lever/STI shifter. Is this correct, or should I be worried about compatibility?

Pretty much right -- you just have to make sure that the calipers have enough reach to brake (on an Allez, pretty much anything but a long reach caliper will work). There are some threads like this with some new Shimano stuff (new Super SLR) which is technically a ymmv/you're on your own, but it should work.

Another thing you should check when replacing the brake is that the cabling was done properly -- bad brake cable routing, for example, can make your brakes not feel good.


Increase saddle height I tried the Xiaomi qicycle electric folding bike and I really liked it.

The only problem is its size. I already know how to raise the handlebar, but I'm not sure how to raise the seat. It should be just about five centimeters higher, in order to fit with my height. I can't replace the seat tube with a longer one, because it's already the longest I can find. I found this product. Its purpose is not to make the seat bar longer, but it would accomplish this goal anyway. I was wondering whether there are other possibilities besides this.

Rinsten Spring

Yes that spring thing will add about 25 mm of extra height once you're seated on it.

On the downside it will make your seat wobblier in all directions.  They make the saddle feel like its coming loose and about to fall off.  Its an unpleasant feeling, though you should get used to it given enough time.

You can get 600mm seat posts, but the difference is probably not worth the cost.

I too have a folding bike that is functionally too small for me.   My plan is to get an engineering firm to fab up a new seatpost from tube, and to use an old-school saddle clamp on the end rather than an integrated saddle clamp.  This will require a minimum of operations, being necking down the top, and applying knurling to the lowest part.

Second option is to find a seat post in two parts.  You might see these on Unicycles where the rider leg length could be a large range.  These tend to have two QR clamps and a substantial length of overlap.  I've not found a useful sized one yet.  These are also built for bikes with little to no sideways pressure, so the bending forces on the post will be increased.

Third option is a bit reversed - if you fit longer cranks to the BB, then your lower foot will be lower again, effectively increasing your seat post length.  However this could get expensive and will only gain you 10mm going from 165 to 175mm cranks.  Then there is the increased risk of pedal strike on turns.

A cheap option is to find the shoes you own with the thinnest sole, and make them your riding shoes.  This will only give a few millimetres thougj


Why aren't Tour de France riders going any faster? I was having a look at the average speeds of the winner of the Tour de France over the years on this page. To help things along I put the data into LibreOffice and produced a plot:

I put on the chart where clipless pedals came in, and I suppose the switch to carbon framed bicycles came in a few years after that (not sure exactly when). What really struck me though was that the average speeds really haven't changed much, especially in the last few years.

There was a big jump in the late 80's/early 90's, some of which could be attributed to the doping practices of the time, but not all of it. Doping of some form or another has been going on since the beginning of the TdF.

It seems really odd to me that given:

improved training
improved nutrition
improved technology

there is only roughly a 10% increase in speed since the 1960s and virtually none in the last decade.

Are we being defrauded by companies trying to sell us all sorts of products (carbon whatnots and sugary goo!)?

The simplest answer to your question is that 1) speeds have increased; but 2) speeds would have increased even more except Tour organizers have been consciously making the Tour harder in order to increase the drama, suspense, and entertainment value of the race. That makes comparisons of overall winner's speed quite complex when combined with normal variations in wind, weather, and team tactics during the race.

First, some historical background. Over time, the winner's average speed in the Tour has indeed increased, especially in the period of the early 1990's and some (including, for a famous example, Greg Lemond, himself a three-time winner of the Tour) have claimed that this is evidence of doping behavior in professional cycling. However, as one of the other answers showed, there is a strong relationship between distance and overall winner's speed. Here is a plot that shows that relationship in the post-WWII period through 2012:

The distance of the Tour has been decreasing due to the rules and regulations of the UCI (the Union Cycliste Internationale), which negotiated a limitation to the length of races and mandated certain numbers of rest days during the Tour with the Professional Riders' Association. From an historical perspective, these limitation were a response to charges that the difficulty of the Tour resulted in riders needing to dope simply to survive, and that by "easing" the stages and inserting rest days there would be less need to dope.

An effect of shorter stages (and higher speeds), perhaps paradoxically, is that race organizers have been increasing the difficulty of the stages; this is particularly noticeable in the other two "Grand Tours", the Giro d'Italia and the Vuelta a Espana but also applies to the Tour: the number and "spacing" of categorized climbs in the Tour has resulted in more difficulty overall. Each year, at the announcements of the routes for each of the Grand Tours, riders and analysts pronounce whether a particular parcours will be relatively difficult or relatively easy, and favoring either sprinters, time trialists, or climbers. That there is a still a strong relationship between length of the Tour and overall speed simply means that the organizers haven't completely compensated for the distance effect with increased difficulty.

And, although your question was not expressly about doping behavior in the pro peloton, a bit more must be said about that. The plot above shows a clear relationship between distance and speed but there is still a question about deviations (or the "residuals") from that relationship. That is, after removing the effect for the length of each Tour, what is the remaining trend in the winner's average speed? The plot below shows that trend with a dotted red line.

As you can see, the winners' average speeds in the 1970's and 1980's were below trend, while speeds in the 1960's, 1990's and 2000's were above the long-term trend. So, even if the long-term trend in speeds can mostly be explained by Tour length (the correlation between Tour length and winner's speed is about 0.8), some have pointed to this secondary effect in the residuals as further evidence of doping. However, there are two counter-arguments, one slightly weaker and one very much stronger. The weaker argument is based on the observation that the residuals are "double-peaked" and speeds in the 1960's were also higher than the trend, then dropped in the 1970's and 1980's. If doping were the simple explanation, one would have to explain the drop in the 1970's and 1980's, not just the rise in the 1990's and 2000's. However, the stronger argument is based on examining data from other races and comparing them to the Tour. If one were to examine the residuals from a similar plot of speed vs. distance for the Giro and Vuelta, one would see that the years when their speeds were above (or below) their own trend lines did not correspond with the same years for the Tour. That is, the speed residual for the Tour and the speed residuals for the Giro or Vuelta are not "synchronized." Thus, if doping behavior explained the reason why Tour speeds were higher than would be predicted from distance, then one would have to explain why doping behavior was different in the Tour and Giro (or Vuelta) in the same year, often with the same riders. Below I include a plot that shows the "residuals" from the Tour (that is, residuals from the regression of winner's average speed on Tour length) plotted against the same residuals for the Giro. This does not mean, of course, that there is no doping in either the Tour or the Giro -- it simply means that one cannot use average speeds as evidence of that doping. Conversely, it also means that one cannot use doping as an explanation for increased average speed. Taken together, it does support the evidence that race organizers's decisions about the routes is a main determinant of the average speed.


Compatible heart rate sensors for CC-RD420DW I purchased a bike computer about a couple of months back; which is a Cateye CC-RD420DW. Now this computer is supposed to provide a cadence and a heart rate monitoring, but the heart rate sensor is sold separately (i.e. Cateye HR-10).

Now I've looked for this heart rate sensor, but it's just too expensive. It costs almost as much as the computer bundled with the cadence sensor itself. Which brings me to My question:

Are there other generic compatible sensors that can work with My computer?

I have a Timex and a Polar heart rate monitor.

Is it possible to configure a different sensor to work with the computer?

Thank you,

Cateye uses proprietary sensors, so I'm afraid that generic ANT+ sensors won't work.  Although it's possible someone has made a copycat sensor that works with Cateye, I doubt it.


How do I place the seat back 20 cm with a full suspension bike? Here are 2 ideas for a makeshift design. The first one is no not that good. The second idea seems more doable using 2 heavy duty seatpost attached luggage racks.
The seatpost is 33mm diameter, dunno if that the official size but it's as close as I could measure it. The seat is great. The bike is aluminium alloy so I wish to keep it light.
Is there a pro solution to putting the seat back like this?

The only safe answer is to buy a bigger bike frame.
When your adaptor fails, you will descend rapidly onto the rear wheel.
The remaining original seatpost has an excellent chance of tearing your chest open, and impaling your head up through the jawbone.
While this is definitely creative, its absolutely not the right answer.
Buy a bigger bike frame.

If you're under 20, then there's a good chance you're still growing.  Even more reason to buy a larger frame bike.


Can I change chainring size on a dirt jump bike? I don't know the name of it but there is a part on single speed bikes. The gear? I think right where the crank is connected. Well on bmx bikes and especially dirt jumping bikes it is really small and if it is small then that means you have to pedal a lot more to go faster. Well can that gear part or whatever is connected to the crank be changed to a bigger single speed to pedal less? Sorry for not knowing the name guys please help though it's important before I buy this bike.

It's called a chain ring and, yes, it can be changed to whatever you want it.

http://www.commencal-store.it/shop/895-thickbox_default/mountain-bike-dirt-jump-commencal-absolut-al-2014.jpg

The dirt bike above has cranks which seem to use chainrings of type 104mm bcd 4-bolt. So any 104 bcd chainring will do the job. E.g:

(source: cyclesportsuk.co.uk)

  if it is small then that means you have to pedal a lot more to go faster

That is correct, but usually those bikes have a very small cog at the rear. So you really don't have to pedal like crazy to go fast. Note though that the main purpose of those bikes is not to go fast but to jump.


Suitable rear mech for Megarange cassettes I just bought an 11-34T 8 speed rear cassette and noticed that it is a Megarange cassette with a substantially large jump between the lowest and 2nd gears.

Will this work with my existing Alivio rear mech or do I need to get a different one? (Such as in this question here)

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.


Very nonstandard question: Is there any way to widen a tire by combining it with some other tire (cut and re-glue)? Brace yourself - this is not normal.

I have an old 22" rim (37-501, 22x1-3/8) and all I can get is skinny tires for it. But I'm an idiot and I really want a wider tire on that rim. I want it so bad I am grasping at straws for ideas.

So here's the thought:

Get a new tire (22x1-3/8)
Get a new BMX 22" tire (which is NOT gonna fit my rim)

Cut the skinny one's beads off with about 1" of rubber above it.
Cut the bead off the BMX tire very low.

Glue BMX tread to old-school beads.

Viola! a 2" wide tire for the old 22" rim.

Yeah, I know this is nuts. But CAN it be done and become whole again?

Maybe, just maybe, someone here knows if this has ever been done. Please let me know.

I don't think what what you are proposing to construct would not be anywhere near strong enough to function properly as a tire.

Tires are not just molded rubber. They are contain a casing of continuous fibers that enables then to withstand inflation pressures and lateral forces caused by cornering.

https://en.wikipedia.org/wiki/Bicycle_tire#Construction

By gluing parts of two tires together you would not have a continuous casing running through the tire.


Which type lockring removal tool do I need I'm trying to learn DIY cassette removal as I want to swap one on a buckled wheel. I have another cassette which uses an FR5 but it doesn't fit this one.

When checking this site it looks like it's a HCW-17 tool but specifically mentions that's for single speed bikes which this is not.  It also says it should have 2-8 splines but mine (and the one in the picture on the site) has 9 splines.

This tool is a fair bit more expensive than the FR-5 tool so I just want to make sure it's the right one before I go ahead.

Any help would be appreciated

I think the smallest sprocket is the lockring on this cassette. I believe you need two chainwhips to remove it.

The smallest sprocket looks very badly worn. I'd replace this cassette rather than re-use.


How can I make it clear to other road users that I'm an inexperienced cyclist? I'm in my mid-20s and I'm currently learning to bike, on my own, as I don't have anyone to teach me. My goal is to be able to commute to work when I want to, be able to travel to nearby towns, and more generally to get over the frustration of not knowing how to bike.
Practicing turns, signals, maneuvering and the like on an empty parking lot is one thing, but I figured if I wanted to do the above, I'd have to actually get on the road at some point, so I've begun biking in the city. I had no extremely close calls so far, but I'm occasionally given "weird" looks by other road users, or honked at. When it's cyclists or pedestrians, I explain that I'm currently learning and ask them what I did wrong; folks are usually receptive ("we've all started somewhere!") and describe what I shouldn't have done, what I did by the book but they didn't expect me to, etc.
However, I can't stop motorists, and shouting "SORRY I'M NEW TO THIS" is unlikely to be heard, and more likely to be misheard as an insult. I have no way of knowing whether I was honked at because I was doing something dangerous, or the driver was just annoyed by me biking slowly, as my current average speed is about 10 km/h (6 mph). At the same time, the driver has no way of knowing whether I'm a cyclist unconcerned by road rules, or just an inexperienced one: people will make the natural (but wrong) assumption than mid-20s me being on a bike means I know what I'm doing.
I'd like to have something to make it blatant to other road users that I'm a newbie. My goal here is twofold:

Motorists being a bit more cautious around me (though they should be to begin with, since as a cyclist I'm more vulnerable than they are)
Not harming the cyclist community by having people think stuff like "cyclists are jerks who behave like they own the place, just look at this one".

Since I'm mostly thinking of high-speed users here, it should be something that can be seen and acknowledged in a second or so. For instance, in my country, young drivers (driving license obtained less than 3 years ago) have to stick an "A-disk" to their trunk:

I've thought of patching one up with a white cloth and red marker, but I'm not sure it's the best thing to do:

I'm not sure how I could make it stay on my backpack;
I have very long hair (it reaches the middle of my butt), which I have trouble keeping tucked under a jacket while biking. I'm afraid my hair may hide the A-disk;
I've never seen a cyclist with one, so I'm not sure motorists would understand it's a serious thing and not some kind of accessory.

What else could I use, or how could I improve the A-disk idea?
Some precisions, if relevant:

Location is a French city with more than 30k inhabitants. From my inexperienced cyclist's point of view, it has a decent amount of bike paths and bike lanes, and the car drivers seem pretty patient (compared to the "cyclist nightmare situation" I've heard of in the biggest cities like Paris, Marseille, etc). I'm careful of taking the routes I've judged to be the most cyclist-friendly, but there are still cars (i.e. danger) on them.
I have a helmet, a bell, a (weak) front light, a pump, side and back reflectors. I am thinking of buying a rear light and a high-visibility jacket.
I can signal but only with my left hand.
I can't bike while standing up on the pedals (yet).
I don't have anyone to ride with me, and I can't attend the biking lessons given in my city (I'm at work when they take place).

I've searched this site for beginner signal, inexperienced, without success; and Googling variations of this question's title only bring up results about learning to bike as an adult, what to think of when biking in the city, etc, not this specific point about "beware the newb" signalling.

This is an interesting and thoughtful question, and just the fact that you are thinking carefully about how other road users think about you is very valuable and will contribute to your safety on the road.
Your question makes a lot of sense. How do you indicate to drivers that you need and deserve their consideration and patience, especially when you have doubts about your own skill on the bike and the road right now?
Unfortunately, I am not sure that being seen as inexperienced will result in drivers being more considerate. I think it is likely to have the opposite effect. Just look how impatient and inconsiderate drivers can be when dealing with a learner driver who holds them up or inconveniences them.
Even children, unfortunately, don't in my experience get treated with more patience or consideration.
My warning would be that making your inexperience clear to other drivers is likely to have negative results.
Three points
Instead, I believe that the key things are to be:

noticed - the driver has to see you in the first place
thought about - can you give the driver reasons to think more carefully about you?
respected - can you give the driver reasons to consider your value and needs?

One of the best things I've read to help think about this is David Martin's Theory of Big. I won't repeat its points here, but I think it's well worth reading.
Regarding those points above:
To be noticed
Are you brightly lit, visible, do you stand out, catch eyes? Do you ride in a visible position, make clear, large signals? How do you dress, and move?
Mostly, these are easy things to do. Riding in a visible position needs confidence though; that's not always so easy.
To be thought about
It's not enough merely to be noticed. You want to take up some space in the thoughts of drivers. What can you do to achieve this?
Unfortunately, once again it often does take some confidence to ride in a way that helps you get thought about.
For example, on a road that I know has pot-holes or gravel in awkward places, I will ostentatiously signal and move widely around them; this can help a driver think "oh, this person moves around and does stuff" (not: "I can slip by this cyclist without a moment's thought or without leaving much room").
If you need to signal, signal in big, clear, impossible-to-miss ways that look like they express meaning. What you signal are your intentions. The physical act of signalling will get you noticed, but the expression of your intention is what will get you thought about.
More: at a traffic light on a busy road, if I am stopped in front of a car, I might pretend to fiddle with a brake or pedal or gear, or tug at the strap of a pannier, just to occupy some attention of a driver while we wait for the lights to change (when? sometimes I just get a feeling that this might be a useful thing to do).
Or, if I spot an on-coming car on a narrow country lane, I will make sure to move clearly across the line of sight of the oncoming driver before slipping in to the side of the road to make room. I don't disappear into a hedge before the driver has seen me.
Generally, you want to ride in ways that are cautious and predictable but without appearing to be too predictable. If a driver is sure that they know what you will do, that can be very dangerous. Better that they are never entirely sure what you will do, so that they stay alert for what you actually do.
I try to look as though I might do something that needs them to respond to appropriately. I want them to imagine that the wheels might suddenly fall off my bike, that my bags might burst open strewing shopping in their path, that I might suddenly stop to admire a flower or greet a friend.
It's important to note: I am absolutely not recommending foolish or dangerous behaviour. Weaving around unnecessarily around other road users is dangerous. Doing unpredictable things is dangerous. Riding on unreliable equipment can be dangerous. Actually having a loose bag is dangerous.
There are two more important ways that help you get thought about. They are to:
Make strong, clear eye-contact
Eye-contact is valuable. You exchange a lot of information - for example, you can communicate an intention - but you also simply place yourself in another's thoughts by it.
Avoid eye-contact
Sometimes, the opposite is called for. If a driver thinks you haven't seen them, they will be thinking about you and wondering what you will do. That's exactly what you want. So sometimes, I studiously avoid catching a driver's eye.
Which of these two techniques you adopt in any particular case will depend on the precise circumstances; I'm not sure I could formulate a clear rule. Both require and demonstrate a kind of confidence.
But either way, you don't want to appear as an uncertain, diffident road-user whose intentions and future actions are of no consequence and don't need to be thought about.
To be respected
Finally, you need to be respected. There are two senses to being respected:
You need to be respected as a human being
People, mostly, will recognise and respect another's humanity. Show that you are a human being, a being like them, to whom they have a duty of care.
The acts described earlier that help you get thought about flow directly into this. Now, as well as being thought about as a road user or as another vehicle on the road, you want to take another step, to be thought about as a human being.
So do human things, and look human.
I might take my hat off (I don't bother wearing a helmet, but it's not a discussion I'm much interested in having) and scratch my head on a long downhill stretch. "Oh," thinks the driver, recognising that I am a person just like them, "that person has an itch." Or I will tuck my top in, or pull it out. I might blow my nose at the traffic lights. Something that shows that I have a human body will never be to my disadvantage.
I'm not suggesting to make your bike rides into an unrelenting pantomime of extravagant gestures and unnecessary actions. You don't need to put on any kind of absurd performance (which in itself would be dangerous). It's rather that what you do, when you do it and who you do it in front of makes a difference, so you need to think about it, and use it to your advantage.
You need to be respected as a respectable road user
As well as automatically deserving respect as a human being, which you'd hope would be recognised by all, it also helps to earn respect. Maybe this shouldn't be necessary, but unfortunately, it often is.
Ride politely and considerately. Obey the rules of the road, and make a point of doing so. Stop at lights. Courteously invite motorists to pull out or pass when it's safe to do so.
If a driver makes way for you, make it clear that you thank them. Don't just wait to notice it, try to catch drivers in the act of being considerate so that you can acknowledge it.
Finally, people often respect people who behave as though they deserve respect. That is a good way to ride: confidently, as though you belong on the roads, as though you expect their consideration and respect. Diffidence and uncertainty will unfortunately lose you that respect from some drivers. Act confidently - such as making signals and decisions - even when you don't feel like it, or at least, as much as you can.
This is why I think that advertising your inexperience can do you more harm than good.
It's really hard to do many of the things that I have advocated above. They take confidence, and experience, and practice. Many of them involve demonstrating your vulnerability as a road user, but not your weakness.
I hope this helps, and I hope it helps think about how you need to appear in the eyes of other road users.
I wish I could offer more useful advice about how to do this, for a person who doesn't know already how to. In the meantime, I hope you enjoy your riding and acquire the confidence you're looking for.


Which rotor, Steel or Titanium comes with Avid CODE brakes? I just bought Avid CODE brakes. It comes with a rotor (200mm). I checked the website and manual and I can't find out if the rotor is stainless steel or the titanium version.

How can I tell?

Information printed on the rotor.

200mm HS1
BOLT TORQUE 55in-lbs 6.2N-m
A01 SEP 11

If a magnet sticks, it's steel.

Happy riding.


Roads that look uphill feel flat and flat looking roads feel uphill. Possible causes? There's a route I usually do that has some specific parts that look uphill but ride and feel as flat, and some parts that look flat but feel as uphill.

Besides this being an optical illusion, which is my pet theory so far, are there any other possible causes for this phenomenon, like type of road, for example?

Our sense of gravity/balance is not very precise on its own and it is combined in the brain with visual clues and other information. For example, it is really difficult to hang a picture straight on a large wall if you don't have a level tool or can align it parallel to the floor/ceiling. There are a few effects that can distort your sense of what is "horizontal".
The Ames room is an optical illusion where you think lines to be perpendicular where in reality they aren't. If the surrounding hills, trees etc. form lines at certain angles (e.g. a ridge on the horizon that your brain expects to be horizontal but that really slopes), you can get a similar effect in nature. Wikipedia explains it in relation to "magnetic mountains" or "gravity hills":

Ames' original design also contained a groove that was positioned such that a ball in it appears to roll uphill, against gravity. Richard Gregory regards this apparent "anti-gravity" effect as more amazing than the apparent size changes, although today it is often not shown when an Ames room is exhibited.
He speculates that "magnetic hills" (also known as "gravity hills") can be explained by this principle. For a magic mountain at an unnamed location in Scotland, he found that a row of trees form a background similar to the setting of an Ames room, making the water in a creek appear to flow uphill.

Also, your brain adjusts the sense of balance over time. You often get this when you cycle up a long steep hill followed by a less steep road with very little inclination. The flatter road may look like actually going downhills (even though it's still uphills) because on the steep climb your brain adjusts and your sense of what is "horizontal" gets tilted a bit. Often, its only when you turn around that you actually get a real sense of the inclination.


Can't Tighten Handlebars I have an old Trek mountain bike with a "Traditional" handlebar stem (Quill stem?) and I've suddenly become unable to adequately tighten the stem to a) remain in line with the wheel and b) stop the handlebars from being pulled clean out of the steering tube.

I've tried taking the stem out of the tube and there was a thin coating of rust over all the surfaces. I cleaned it all off with a wire brush and went inside the steering tube as best I could. This never had any significant effect.

It is not possible to tighten the nut any more yet the "wedge" no longer seems to generate enough friction to grip the forks. What can be causing this and what can I do to fix it?

EDIT In response to the question by ChrisH, here is a photo showing the wedge properly displaced from the stem as I understand it is supposed to work.

I'd guess that there are two possible causes.

Old age.  Your wedge as pictured shows some clear flat spots on the ridges that are supposed to bite into the inside of the steerer tube (the receiver that forms the top of the forks)   So its very likely the steerer has equivalent wear on the inside, and you're simply seeing a lack of grip.

First fix would be to file the wedge so its got more obvious ridges in it.  Use a triangular file, or the edge of a quarter-round file for metal.  Do be conscious of metal shavings and avoid getting them near bearings.

Another repair plan would be to buy a new wedge - this probably means a new/replacement quill stem.  If there's a bike coop near you they might be able to help.

The other cause is damage or wear inside the steerer tube.  This is impossible to fix, you'd have to replace the front fork completely.  To check, you need to undo the threadded headset and drop the fork out the bottom of the bike.

You're looking for bends or swellings or even holes in the outside of the steerer tube, or significant wear marks inside.

Dropping out the fork also allows you to service/replace headset bearings too and clean out the bearing races, which may be due given its age.


Will it cause problems if I use components from different series? If I set up a bike with:

10-speed tiagra shifters
10-speed dura ace read derailleur
9-speed 105 front derailleur

Will it cause problems if I use components from different series? (All of these are from within the past year or two.)

Your best performance will come from using components which were designed to work together, i.e. with the complete drive train from the same year and series. That doesn't mean that different combinations will not work together at all, however.

While I have occasionally used a 9 speed front derailleur with a 10 speed drivetrain as an emergency fix, it shouldn't be used for a permanent set up. Your shifting performance will suffer, even if they are both double or both triple components.

In addition, the year and model of the Dura Ace components matters. The 7900 STI levers, which are current Dura Ace, have compatibility issues with the 7800 front derailleur of just 2 years ago, even though Shimano says they are fully compatible.

I've added scans of the Shimano 2012 Compatibility charts for front and rear drive train components. You will notice that no 9 speed part is listed as compatible with any 10 speed part, but that even the new 4600 Tiagra 10-speed is listed as compatible with all 10 speed components.

I hope that helps.

Shimano Front Derailleur Compatibility Chart

Shimano Rear Derailleur Compatibility Chart


700x25c tubes inside 700x23c tyre I'm riding on 700x23c tyres with 700x23c tubes, road bike. I've obtained a box of 700x25c tubes. While I'm taking the approach that it's always best to fit the correct size, I'd like to either use, sell or give away these 700x25c tubes.

If I use them:

Will I encounter problems?
How soon will these issues occur?
What sort of problems may occur?

There is a similar question, although it deals with borderline issues, not explicitly with incorrect sizes.

What inner tube size to get for my road bike?

They'll be fine - I'd certainly use them without question in a 23mm tyre.

Most tubes cover a range like 18-25 and 25-38.  Given 23 and 25 are in the same range I'd expect it to work correctly.

If you have access to a spare 23 and these 25mm tubes, compare them.  I bet they're identical in size, or so close to it that the difference is immaterial.

Tubes are consumables, you'll use them up eventually.

Other options:

Stick one in your saddle bag as the last resort second spare.
Give them away.
Buy a 25mm tyre and try it out (if your bike frame can fit one)


Ladies bike on a car rack I need to transport an "open frame" bike on a Saris Bones 3 car rack. This is the bike - http://arragons.com/online-store/bikes/hybrid-bikes/ridgeback-element-open-frame - and this is the rack - http://www.wiggle.co.uk/saris-bones-3-bike-rack/.

I'd like to like to know whether I need to shell out for one of these bars - http://www.wiggle.co.uk/saris-bike-beam-bar/ - which create a temporary top tube for ladies bike. The top tube on the bike in question doesn't seem that low so I might get away without the bar.

What would the effects of not using a bar? I've read that these bars are necessary for ladies bikes, but why if all it means is the bike sits more level? Will the rack be unstable? Will it mean other bikes won't fit on the rack? etc etc

It depends on the exact size. To figure it out, you'd need some detailed measurements. If it fits, there's really no problem.

It's more likely a problem with a "ladies" (low top tube) bike if it's smallest size and/or if the frame is sized for a suspension fork.

Look at the picture of the bike. See how the distance between the top tube and the down tube is quite narrow up by the head tube? It's possible that with the smaller sizes of this bike, there isn't enough room to fit both of the bike rack's posts inside that triangle.

However, that bike comes in 3 different sizes. The bigger sizes have a longer head tube and a longer top tube, so there's more room.

If the bike fits on the rack without that "beam" bar, there's really no significant problem. There won't be any rack stability issues, since the weight of the bike really doesn't change much with that tilt. The handlebars probably won't tilt far enough to hit anything. It's possible that it will interfere with fitting 3 bikes on the rack, since the rear wheel will be up where the bike next to it's handlebars need to go.


Unusual bottom bracket shell I broke my bottom bracket axle a few days ago, and when I removed the crankarms I discovered my old bike is using a cup and cone bottom bracket but more importantly the bracket shell is a bit odd. It is not threaded, the left cup is stuck or glued to it and goes all the way until the right side of the shell. On the right side it is threaded and allows the right cup to be screwed in it. I have included a few pics.

First pic is the left side of the shell, the broken axle is still there, you can see an hexagonal piece that screws around the left cup to secure it to the shell I guess, although the left cup is already firmly glued to the shell and doesn't really move.

Second pic is the left cup naked. You can see a little space between the shell and the cup all around it. And how it goes all the way until the right side of the shell.

Third pic is the right side of the shell. The left cup seems more firmly attached to the shell on this side. There seems to be some glue between the cup and the shell. The inside of the cup is threaded to allow for screwing the right cup.

Have you ever seen that kind of system? Is it safe? I was planning to clean the cup, clean the bearings (maybe throw some new ones), grease and replace the bearings, put a new axle, close and seal everything, and finally screw the crank arms. Is this the correct procedure to replace this kind of bottom bracket?

I'll put some thoughts that appeared in the comments:

  I've googled and came across someone else with similar problem: bikeradar.com/forums/viewtopic.php?t=12592913 - there is a cross-section of this bottom bracket:

  Looks to me like a French invention.

  I wouldn't try to remove the "fixed" cup. Just like you said - clean everything, find a new axle and assemble it back again. If you remove the whole set you end up with a threadless BB frame and those are said to be not worth to be brought back to life.

Suggestion of Batman:

  Depending on what the threadless BB frame is like, you can use threadless BB's like the velo orange grand cru one

which I agree to, however the price tag on Velo Orange bottom brackets is hefty. It may be worth if the frame has substantial value either financially or emotionally to you.

From my own experience - I have a bicycle with high emotional value which has Thompson BB (pressed in cups). The BB shell is 42mm in diameter. Velo Orange has a solution for that however it exceeded my budget. I was lucky enough to find a press-in Thompson/Thun replacement of sealed bearings cartridge with a square-taper spindle (the original was cottered, hence the idea of replacing it).

In the meantime I came with an idea for you. Since it is a road bike, perhaps it would be possible to upgrade the BB to, let's say, Hollowtech? You'd have to measure the inside diameter of the BB shell (dark blue in the cross-section, labelled as Frame) and check if press-in Hollowtech bearing cups exist, maybe some adapter shells will be necessary.

Another idea is, if you want to stay with some vintage yet standard stuff is to press in a complete BSC threaded shell:

This one I've found here: http://www.wiggle.nl/sram-pressfit-30-naar-bsa-adapter/ - seems quite "generic" and available in more countries.

Then, when having BSC threads you can simply put sealed bearings cartridge with square-taper spindle and enjoy the maintenance-free bottom bracket.

But again - my choice would be to find a new spindle (since you already have a square taper) if the spindle is of standard measurement, replace the bearings and assemble it back again - there is only one cup and cone to adjust and, as I can see in your pictures, there are the lip seals on the BB spindle making the whole package quite sealed, thus maintenance-free.


Is lithium grease suitable for lubricating the steel headset cups when pressing them into the aluminium frame? Can I use lithium (lithium soap based) grease for lubricating the steel headset cups when pressing them into the aluminium frame?
I mean cups, not the bearings inside them.
Is it good for preventing corrosion on steel/aluminium contact?

Yes, totally suitable. Of all the remotely common grease types, there's not really a scenario on bikes where the type matters for this application unless it's a titanium or stainless frame, and then use anti-seize.
As someone who presses things into bike frames on a regular basis and lives/works in a rainy climate, I do always use grease, but it's primarily for information, not corrosion resistance. Greasing the surface every time comes close to normalizing the contribution that surface friction makes to the force required, so problems with the press fit are easier to pick out in both the too loose or too tight direction.


What brand / model of brake is this modified U-brake? I have been searching for a while, and I cannot find any information on my rear u-brake. It has served me well for many years (10+), and has a surprising amount of force. It's stronger than any cantilever and most V-brakes I've ever used or felt. Adjusted for maximum power, it has crushed a few single walled rims for me, so I usually adjust it off peak for the sake of my rims (though it would probably be fine with dual walled ones). This isn't to say it's phenomenal, it's difficult to get wide tires through it, and if it's not adjusted properly it will hit the knobbies on large tires.
I have searched every millimeter of it for any markings or lettering, and it is devoid of any. If anyone has seen one like this, or can identify the brand or model, I'd like to know more about the company, the design, and the specifications.
Unidentified U-Brake

With Brake Booster Removed

The closest I've seen yet is a roller cam u-brake, like the one below, only without the rollers:
Roller Cam U-Brake

They weren't original to the bicycle, but the frame is a 1997 GT Bravado, the brakes were purchased around 1997-1999. It came as a 1 1/8" threaded / 21 speed setup.

I think those are McMahon Racing Components, possibly their "Power-Link" model. See:

http://mombat.org/MOMBAT/BikeHistoryPages/McMahon.html

http://www.blackbirdsf.org/brake_obscura/mtb.html


Road Bike Survivability I'm considering getting my first road bike, a departure from the mountain bikes I've ridden in the past. I've heard that road bikes are ideal for asphalt-paved roads and paths, but I'm curious as to how much they're able to withstand. Particularly, I'm wondering if they'll be able to survive kinda badly paved roads where the ground is still flat but there's bits of gravel and dents in the ground, along with the occasional rock (like the C&O Canal trail to DC).

Basically, what's the worst trail that the average road bike should be able to withstand?

These days there is a range of drop bar 'road' bikes with a spectrum of capabilities. Using some of Specialized's current range to illustrate:

You can ride a 'race' bike such as the Tarmac with narrow, slick 23mm tires on a gravel or poorly paved surface, but it's not much fun, and you risk puncturing of damaging the wheels.

The Diverge with it's 30mm tire does better, but don't expect to crash it over large potholes without consequence.

The Sequoia with 27.5" wheels and 42mm tires is in mountain bike wheel territory and obviously deals with rough surfaces much better.

Basically bigger tires means better rough surface capability, but at the expense of heavier, harder to accelerate wheels.

For the C&O Canal towpath - a trail I'm very familiar with (fairly smooth crushed gravel, a few ruts and potholes) - a tire 28-35mm with some tread will probably work.

Update:

I ran my new bike with 28mm slick tires on the Fairfax County Connector Trail which is far rougher than the C&O Canal towpath trail this weekend with no issues. 28mm on the C&O will be fine, although I still recommend a tire with some tread.


Ergonomics - road cycling on mountain bike I am new to cycling and have recently started to bike to work.
The distance is about 20 kms each way and I find that by the end of it my lower back starts to hurt.
I do work at a desk job and I probably do already have a bad sitting posture; which I'm trying to correct.
I was wondering what is the proper posture to ride on a mountain bike comfortably for about 1 hour ride. Or if this lower back pain is due to my back simply not being strong enough to lift my upper body as I'm sitting on the bike.
I'm looking for rule of thumb tips such as your seat should be high enough so that your leg is just reaching the pedal at a full extension.
Thanks!!

If you're rocking your hips while pedalling then your saddle is too high relative to the pedals, for your leg length.
Raise your saddle until you do start rocking while riding, and then lower it a couple cm or an inch.
If you now can't reach the road with your foot when stopped, then you will need to lean the bike, or get off the saddle at a red light.
This is not specific to MTB, but having a saddle that high might make MTB riding less controllable.  If you ride off road, lower your saddle again by a bit.  Draw two lines on the seatpost to help find your heights when adjusting.


Custom/universal clamp/attachment for light on rear rack A long time ago i bought one of these lights from china

It is pure chinese crap. bought 2. one dead in a few days. Then i broke the two trays that i slide it to attach to the bike making them useless paperweight since they have a uncommon attachment tray that i can't find alternatives. Not to mention the included attachments are only good for seat-post installation, which is idiot, since the laser will be blocked by your legs! this thing has to be installed behind the bike.

Now i'm wanting to add that light to the bike again. And in the process, find/design a generic attachment for lights on racks. The back of the light is flat and has plenty of space. Also there is lot of space inside for me to use with fasteners and what not.

The rack i have is similar to this one:

It has a flat pane. With 3 holes.

Is there anything ready made that came with both parts? I can only find things for specific formats. I was wishing for something that I can just screw in a male plug in the back of the light and then secure the other female part on the bike or so.

I am dreaming with something like this, but that would also include the other part, also with screws.

Some hackish ideas I have:

Why not just use zip ties? If your rack doesn't have 3 posts, you can make 2 or so loops (one or two horizontal, and 1 or 2 vertical) to make a makeshift mount. Then, attach something like a binder clip or two to the light. Alternatively, you could cut a bit of the light's plastic and use something like a velcro loop on the back. _v_v___v_v_ where the _ denotes the back of the light and v denotes entry & exit points of velcro (if it doesn't need to be removable, you can even use zip ties instead, and seal the light a bit with a little bit of caulk).

If you want to be fancy, you can always take the mount of some manufacturer (e.g. Planet Bike), and then get a piece of plastic / other stiff material, and rabbet the appropriate thickness ridge to fit into the mount (or glue a thin piece of material to a thicker piece material) to get the rabbet-ing effect. So, the thin part would be thin enough to slide through the mount, and the thick part would be attached securely to the light (through some adhesive, or screws). Then, you'd make the top a bit too wide for it to slide straight down through the mount. If you have an arts and crafts store nearby, you can pick up some thin but rigid plastic, screw in / glue a block of some other material narrower than the ridge of the mount and then put a screw through the light into the block. Then, on top of the block, put a lip so the light doesn't jump out. If you cut the block so that it conforms to the notch in the light mount, that would help too. Alternatively, you can cut a slot in the light mount and thread some velcro through it.

You can also cannibalize another light with matching mount by simply cutting off a bit of area around where the mount is, and then adjoining it to a new light (screws/adhesive).

As for the general problem:

Typically, mounts are isolated between manufacturers (certainly, on front lights. on rear lights, it seems to primarily be a width thing). So a universal solution is going to be hard to find / doesn't exist. For cheap lights, I'd be inclined to just get a new light.


Is a leather saddle appropriate for all-weather riding? In our climate, it rains pretty steadily for 3 seasons. Would a leather saddle (like a Brooks) be appropriate for my bike, or should I look for a different material?

I've used a Brooks saddle in a similar climate (Vancouver, BC) without any major issues.  Treat the topside with Proofide every 6-12 months and keep the underside dry (fenders, wedge bag, etc).  Store the bike in a dry place between rides so that the leather can dry out naturally.  A saddle cover would probably help but I've never used one.


Replacing a crankset after 1 hour! First time here!
My brand new bike arrived this evening and I’ve broken it with an hour.
It’s a Vitus Nucleus 27 VR Bike (Altus 2x9) 2020
I took it out and about 50 mins into the ride I noticed the right pedal was feeling a bit off.
I just had the default plastic pedals on so assumed I’d just pushed them too hard.
Turns out I must have cross threaded the pedal and now there’s no thread left in my drive side crank arm.
The crankset is the SR Suntour XCM 36/22T 175mm.
I can’t find a direct replacement - it’s out of stock everywhere.
My question: What are my options for replacing this? Is there another crankset that I could easily slot into place? Is there an obvious upgrade?
Thanks for your help!

You could replace the crank with any Shimano 2x9 crank for a square taper cartridge bottom bracket (with the same chainring sizes are crank arm length or course). If the bike is equipped with an Altus groupset then an Altus 2x9 crank would be a reasonable choice.
There is a bit of an annoying wrinkle to this, different square taper crank models require different specific axle lengths to achieve the correct chainline. The existing bottom bracket axle might not be the correct length for the crank you choose.
As an example The Vitus Nucleus 27 VR page helpfully tells us the the BB axle length is 113.5mm. The Altus FC-MT101-2 crank needs a 'LL123' code bottom bracket axle which I think is actually 122.5mm.
Often it's easier to buy and install a crank and the correct bottom bracket at the same time. This also opens up the possibility of a 2x9 crank with a Hollowtech II external cup bottom bracket, which I think are in the Acera line and would be an upgrade.
Special tools are required to remove and install bottom brackets, and a crank puller is needed to get crank arms off square taper axles. Bottom brackets and crank arms should also be installed with a torque wrench. It's especially critical to get square taper crank arms tightened properly.
If you had a an issue with pedal installation you'd probably want a bike repair shop to do the installation for you, and they will of course have the tools.


Will I break my Dahon Mu Uno? I weigh around 220 pounds, the weight limit for the bike is 230 pounds, part of my regular ride is a long stretch of compacted gravel, I tend to thrash along being used to riding a mountain bike and the less than a year old Mu Uno has already developed a squeak. Am I going to break it?

Weight limits are usually based on what the wheels can take rather than the frame. Also like with most things nowadays the manufacturers build in a margin of error so you can likely ride it safely 10-15 lbs above the actual limit.

Riding on compact gravel should not bother the bike so long as you keep it clean - make sure dust isn't getting into the hinges. To rule out any issues with the hinges clean them thoroughly and apply a light coat of quality lube something like Dumonde or Finishline. Then ride the bike and see if the creak gets any better. If it does, there may be some play in your hinges. A good bike shop should be able to adjust that play for you. If it does not get better the culprit is likely somewhere else. Possible sources could be the saddle mount or bottom bracket area.


Effects of rust on steel frame strength I have some rust on my front forks. This question tells me how to deal with it, but I'd like to know whether it will be impacting the structural integrity of the forks.

I'm planning on going touring (on-road) and therefore loading the forks with a low-riders and panniers. If I clean this off and re-seal/paint over it, will my forks still be structurally sound?
The bike is a Dawes Super Galaxy, probably from the late 80s.

Consider using rust converter before repainting the said area. From the picture, the rust doesn't look to be that bad since pinholes haven't formed and the surface is smooth.
Sand the rusted area down and apply a bit of rust converter. For primer, you could use epoxy which works better and is a lot better for wet conditions. Polyurethane paint also works well for steel bikes exposed to harsh elements.


Small wheel bike to be converted to bigger wheels I have a cycle with small wheels. I had been using it as a child. now I am an adult and I want to replace the small wheels with 26 inches wheels without spending a large amount of money.  I have thought of either putting wheel on the side to make a quadricycle. or welding a small piece of metal to the frame so as to be able to put a bigger wheel.

Is any other way?

Cheapest, safest and most practical option option would be to sell and buy  a second hand bike.

For instance I just sold and old, but perfectly usable full suspension MTB that originally cost about $US3500 in 1995 for $US60.00. The buyer got a bargain and I got some space back in my garage. Look for someone who wants some garage space back....

If however you are wanting to make a franken-bike for fun, you will also need to consider the increased wheel size will probably need different gearing, and the frame will be subjected to quite different forces than what it was designed for. You would need new chain, new wheels and tires. Brakes may not be in the right places and might not fit. As it was a kids bike the cranks might be too short.


I am always having a broken spoke once in every 500Km I have a Giant Escape hybrid bike, which I bought as a secondhand bicycle. After I had bought it, once in every 500km, according to Strava records, I am always having a broken spoke in rear wheel. Yesterday, I got my sixth broken spoke and I have noticed the old spokes broken always, not the ones I had replaced.

I asked from a few repair persons but they just replaced the spoke without reasoning. Is there anything I can do to stop this? Because I think this is strange.

As you can see in this picture most of the broken spokes are on drive side. As I remember I heard sound of breaking when I tried to speed up quickly.

Most of the time the spokes break at the J Bend, not the nipple/rim.  They all broke in the rear wheel, none in the front wheel.  Most are on the drive side, and few are on the non-drive side.

I am more or less 85kg (187 pounds) who commutes 8km/5miles up and down (16km/10 miles daily) with, most probably, 2kg (4.4 pound/ 4lb7oz) bag. While riding I have to go on concrete roads, uneven terrain, for about 2km/2200 yards. Moreover, I used to ride more than 50km/31 miles on weekends.

Check if all spokes are properly tightened. if some spokes are too loose that can put extra stress on the rest of the spokes which can cause premature failure.
If so (some of the spokes are not properly tensioned) you should true the wheel (or have it done if you don't feel comfortable doing it yourself).

Is the back wheel the original back wheel that came with the bike or has it been replaced with an aftermarket rear wheel? If so it might be of lesser quality (in which case the spokes will most likely also be of lesser quality).

How old is the bicycle/how old are the wheels? Metal gets 'tired' after a certain number of load cycles ( https://en.wikipedia.org/wiki/Fatigue_(material) ).
(If the spokes break when trying to tighten them to a normal level the problem is most likely metal fatigue and you should either replace all spokes or replace the wheel (the latter is a more realistic option)). If the wheel is indeed quite old, the spokes are all properly tensioned and there is no other reason to suspect spoke failure metal fatigue might be the issue, if so (as afore mentioned) either replace all (old still remaining) spokes or replace the wheel (which is more conveneint/also cheaper in most cases). Spokes are quite cheap but rebuilding the wheel will take a considerable amount of time.

Where are the spokes failing (at what point on the spoke do they break, near the nipple, near the j-bent?) Can you add an image of the surface of the spoke at the break point? The type of surface at the failure point can give an indication of the failure mode (if it failed due to fatigue or overloading (putting too much stress on the spoke).

I quote:

  Fatigue usually begins from a stress concentration at the surface. The fatigue cracks grow slowly and usually leaves a striated pattern that looks like a smooth sea shell. Then, when the crack has gone far enough, the object will break suddenly due to the stress in the small remaining area exceeding the ultimate strength. This sudden fracture will usually look different - rough or torn looking.

Source: http://www.learneasy.info/MDME/MEMmods/MEM30007A/properties/Properties.html

Source: https://www.fastenal.com/en/3289/fastener-fatigue

Source: https://www.sciencedirect.com/topics/engineering/tensiles


What 's the size of bearing? What's the size of ball bearing on WH-R550 hub, is it 1/4" for the front one and rear one ?
Can I replace them with 1/4" ceramic bearing ?

Thanks

According to Boca, they are 3/16" for the front and 1/4" for the rear.  I see no reason why you can't run ceramic bearings in them.


Disc brake rotor scraping against mounting bracket (My question is related to Rear disc brake rotor rubbing against caliper frame mount? but I hope to provide some more context & photos.)

I have a Rocky Mountain Edge mountain bike (possibly 2011 or 2012) that has factory-installed Shimano hydraulic disc brakes. I was replacing a flat front tire today and had trouble getting the rotor aligned inside the caliper. When I took a closer look, I was surprised to see that the disc has been rubbing against the front fork mounting bracket along at least half of its radius.

This photo shows the wear to the mounting bracket and the caliper support (there is corresponding wear on the rotor):

(n.b. the bike was upside down when this photo was taken: dropouts are on the left, and the rear of the bike is toward the right.)

To me, it seems like there's an issue with where the wheel sits relative to the fork (i.e. that it's a few millimetres too close to the caliper side). The rotor seems to be permanently affixed to the wheel (no screws), and it doesn't appear to have moved relative to the hub. Looking at the quick-release skewer, it seems like all the parts are there, but it still doesn't sit properly.

How can I solve this problem? Is there a spacer I can add to the quick-release skewer so the rotor sits the proper distance from the fork? Is there a specific offset for this type of brake caliper?

Is it likely to be caused by a damaged wheel? (The rim is quite out of shape, so I could use this as an opportunity to replace the whole wheel.)

EDIT: some more photos:

A few things can cause this:

In theory it could be a problem with the alignment of the mounting posts on the fork. This isn't likely for a few reasons. One is that the problem would have been pretty egregious if the bike was doing it from day one, i.e. the wheel wouldn't have turned and someone would have noticed. Another is that suspension forks rarely have such problems because the brake mount is usually part of the same casting as the dropout, and in that case you're not going to have random one-off problems with bad positioning of the mounts due to fixturing errors at the factory, which does sometimes happen with frames.
A sufficiently out of true rotor could do this.
If the wheel were installed out of alignment in the fork and ridden it could cause this.
If the hub parts were put together wrong, after service for example, it could do this by creating an incorrect distance between the rotor surface and the left locknut service. Between the plane of the back shoulder area of the centerlock mount and the plane of the left dropout should be about 19.5mm. If this happened, it would also throw off the wheel dish unless that was corrected afterward to compensate.


What is the maximum or minimum tire width I can fit on my bicycle We often get questions on bicycles.stackexchange about fitting wider or narrower tires to bicycles. We have a large number of these with answers suiting the specific bike or style of bicycle in question, but I have been unable to find one that provides a generic answer covering off all things that need to be considered. For most bicycles, the answer is the same regardless of the specific style and sizes of tires in question.

This is intended as a canonical question that we can point closed questions to.

Maximum tire width is dependent on two main factors, clearance at the frame/fork, and the width of the rim.
As for the frame clearance this can usually be visually inspected and easily distinguished if a larger tire than the present tire will cause issues. Brakes such as V-brakes or cantilevers may also cause clearance problems with some tires so attention should be paid to them as well.
Mud or other debris should also be considered for mountain bikes and applications with fenders/mudguards. You should not run clearances so tight that one little pebble caught in the tread will hit the frame, fenders or other parts.
Think of the difference between both sizes you are considering and then split that number in half, that is the distance you will need to be able to clear on either side of the tire at the chainstay essentially. So if there is a 4 mm difference in road tires, the new size will roughly add an additional 2mm onto either side of the existing tire is one way to think about it, but the top of the tire needs to also be checked as the new tire may also be taller in addition to the increased width.
Knobs on MTB tires can also vary greatly and play a part in your decisions and fitment as well. One 2.25" tire may come out to be shorter than another more aggressive 2.25" tire due to the shape and size of the knobs.
As for rim to tire interface there are multiple guidance charts available online that give a rough estimate if a tire is compatible with a certain rim width, such as this one from J&B Importer's, a bicycle parts distributor's catalog.
As an example you can see that a rim width of 19mm (top row) should be compatible with tire width of 28mm/1.10" through 62mm or about 2.5". But seeing as 28mm is the lower end of that column somewhere in the 2.2/2.35 range would be a safer bet.

However just because it will fit on the rim does not mean it will not rub on the frame so that is what is most important.
For small changes such as from 26 x 1.95 to 26 x 2.125, or 700C x 23 to 700C x 25 you are almost certainly safe from a rim standpoint if the bicycle was factory equipped with 1.95"/700x23 tires.
To be certain, the model of rim should be referenced and the width noted.
Please also note that the same applies to going to a smaller tire size, too small of a tire on the same rim could not seal well and potentially cause flats or blowouts when the tire bead cannot seal against the rim well enough.
Edit: July 2020 - Suggest reading the the answer posted by @Weiwen Ng which contains updated information.


Clicking gears on new Electra Townie 8i I asked a similar question related to slipping gears here:

Slipping gears on new Electra Townie 8i

but now I no longer get slipping, but clicking noise when the pedals are rotated either forward or backward direction, but not when coasting and the pedals are not moving.  When in low gear, the clicking is faster and slower in high gear.

Could this clicking be the chain clicking on the sprockets of the gears?  What is the source of this noise and how can I fix it?  My other Townie 8i does not have this noise.

It can be many issues, but a click in the hub which is a rotary noise, is usually the Chain guard or the dust cap on the hub behind the cog which has popped out of place, or possibly cracked.

The noise is not detrimental to the safety of the bike, but you should find a shop that has experience repairing these hubs, and get them to do a rebuild.


What is the best method to teach a young child to ride? My daughter is just about ready to start to ride a proper bike.
I am loathe to get her a bike with training wheels/stabilisers, as just about every kid I see with them just relies on them and doesn't learn to balance properly.
What is the best method to get her riding properly?

You're absolutely right--children's bicycles with training wheels are good for exercise and entertainment, but they do little to nothing for balance.

In my experience, the best way to teach anyone--children included--to ride a bicycle is to take the pedals off, lower the seat, and let them scoot & coast around until they develop the proper balance. Then, add the pedals, and let them coast, pedal, etc.

For children, there are several popular brand that makes 'run bikes', which are usually made out of wood, and have neither training wheels nor pedals. They are low enough that the child can sit in the saddle and place both feet on the ground, but high enough that they can still propel themselves & lift their feet to coast.

These bikes allow the child to quickly and safely develop good bicycle balance.

(See http://www.earlyrider.com/, http://www.runbikes.com/, and http://www.likeabikeusa.com/)


Chain going "slack" on the 7th gear under load on a new mountain bike? I recently bought a new Mountain Bike which works pretty well, aside from the fact that I have a problem with it which creates a pretty damn large safety hazard, not to mention creates a massive headache for me.

I'll be in the 7th gear, and when I start to stand up/put a lot of pressure on the pedals - I'm not really sure how to explain this - it feels like my chain slacks for a moment, and my pedals kind of jerk and then everything goes back to normal for a moment, before going back to slacking again.

This ONLY happens in the 7th gear. It used to happen sometimes in the 6th gear, but I messed around with my H/L screws and barrel adjuster and now it only happens in the 7th gear. I'm not sure what is causing the problem.

Does anyone have some advice for me? I've tried adjusting my barrel adjuster over and over again and I can't seem to narrow it down to being that.

Could it be a problem with the H/L screws?

I REALLY need to figure it out, because right now I pretty much can't use my 7th gear because I'm afraid one of these bad "jerks" will cause me to crash, as I've come close to doing it before.

Does the bike have multiple chainrings? Make sure you aren't cross-shifting- that is, shifting into a gear that is too high/low for the chainring that the chain is sitting on. This can cause a problem like you've described- chain rubbing on front derailleur and constantly attempting to shift to put the chain into a more linear position.


Shimano error code: LO EAT On my Specialized Como electric bicycle, the Shimano display is showing LO EAT. What does this error code mean? I tried turning the bike off and back on again but the error display doesn't go away.

At a guess, your ebike has a main rechargeable battery and a separate coin cell battery in the controller, aka the TCD or Turbo Connect Display.
The warning says "LO BAT" for Low Battery, and you'll need to replace the CR2032 3V coin cell that keeps the bike's memory alive when the main battery is removed or flat.
I don't have one, but searching suggests you rotate the computer/head unit by 90 degrees, then it lifts off the mount.  Underneath is a common cr2032 access hole.  Rotate it with your fingers, or perhaps plier tips, then see the old battery inside and swap a new one in.

For more info, read the friendly manual at  https://media.specialized.com/support/collateral/0000108340.pdf
Note your odometer will be reset by changing the battery, so maybe you want to note it down first, if possible.   You may also need to re-pair the head unit with the other components, which is also described in the manual linked above.


Exceptions to 3/8x24 for coaster axle threads? Is there such a thing as a contemporary coaster hub that uses 10x1 or 3/8x26? Trying to figure something out without the bike in front of me.

Not going to say there isn't a fringe case on an old or rare specialty brand hub, but all I've ever seen and worked on have always had 3/8 24tpi axles.  I believe some Sturmey-Archer internal gear hubs use something different, but I thought I remembered it being 13/32 or something.


Ultegra shifting issue Relatively recent (within 5 years) Ultegra 11-speed set up on internally routed carbon frame.
Replaced cables.
Rear mech. shifts fine...until front mech. is shifted to the big ring.
When there is tension on front cable, rear will not make it to largest cog, and has trouble downshifting.
EDIT: Just removed and reinstalled cables again, this time using two extra pieces of cable housing to attempt to keep the cables organized while routing.  Removed the extra housing once the cables were through.  Re-assembled....issue is still present.
NEW UPDATE: Still trying to figure out how increasing tension of the FD (when shifting to big ring) decreases cable tension on the RD. So that when the chain is on the big ring up front, the rear will not shift to the largest cog.  Leading theory is there is something amiss with the cable routing as proposed by @Nathan Knutson.  Here are some pics.  Does anyone see anything suspicious?  Missing parts?
MORE RECENT UPDATE: Checked chain sizing (in light of a comment below), using the method of bypassing the rear derailleur and wrapping the chain around the largest cog and the large chain ring.  The chain appears to be the correct length.
Is it possible that the cables or routing is a red herring, and my issues is somewhere else, like the  rear derailleur itself?  ...though hard for me to believe because it shifts correctly when in the small chain ring up front.

I looked at some pictures of the bike.

The thing that fits most of your symptoms is that when the FD cable is under tension, it does something to the alignment of the guide plate that the cables are wrapping around, pulling it closer in against the frame such that the RD cable suddenly has tension relieved from it and therefore can't make it up to the big cog, and downshifts with more hesitation.
That you say the problem also exists when the FD cable is disconnected completely is curious, because it's a little like saying the problem happens when there's tension on the cable and also when there's not. Maybe that also misaligns or destabilizes the guide somehow.
Barring other options, I would pull the cranks and BB and see what you're working with in there. It's possible something has happend that has caused the guide to not be supported properly. You may be able to feel it happening by putting a finger against the plate while the other hand shifts the front.
Another thing to look at would be if you adjust the RD to be at the right tension with the FD in the big ring, does it have the opposite problem in the other direction? It seems like it probably would, but it's worth checking.
The other possibility I can imagine is that it has to do with the internal crossing. Usually one would assume this symptom wouldn't be caused that way, because one cable becoming straighter under tension could contort another cable crossing it in a way that increases tension to that other cable, but decreasing the tension is hard to see. But, perhaps they're crossing each other near the contact point with the guide plate in a way where it makes that possible. If you can reverse which cable is crossing over the top, it's possible that could fix it or you could at least learn more. Also, most frames like this can have the housings set up to not cross the head tube, and thus have no internal crossing, but it will come at the cost of much less clean housing lines up front and likely more housing rub on the frame.