Do you oscillate your diet along with your riding? Briefly
If on alternate days you cycle and rest, and your ride uses, say, 1200 calories, what's better, to eat 2600 calories daily (and then where does the deficit come from on the riding days?) or to alternate between 3200 and 2000 calories (and what kind of diet supplies you with 3200 without disturbing your digestive system?).
For the impatient, let me illustrate the question with a figure.

Not So Briefly
My cyclocomputer tells me that my ride used 1200 calories. I'm here not trying to determine whether the figure is accurate. I'm trying to better understand the appropriate diet for a workout that uses such a substantial fraction (or, for some, a multiple) of the basic daily caloric needs. The other question (how can we—or how does a cyclocomputer—determine the calories used given distances, altitudes, heart rate samples, and speeds) is a very interesting question, but it is not the subject of the present discussion.
Since going through what was most likely "hitting the wall," I've been cautious to eat more, especially carbs.
During the ride I can get 350 or so calories from three small snacks.
Right after the ride I attempt to use this glycogen replenishment window and consume 170 g (about a third of a pasta package) to get ~550 calories heavy in carbs. With a sauce and fruits this after-the-ride lunch might add up to 800 calories, which is not too far from what an adult might need without a workout (assuming vaguely 400+800+800 for the three meals).
The purpose of this worked-out example is to illustrates the difficulty of attempting to reach 3200 calories in a day.
If I did this route daily, it would be simple enough. Rather than the daily ~2000, I'd aim to consume ~3200 calories daily.
But, in full humility, admiration, and respect for those who can climb three mountain ranges racing one day and still be expected to repeat the feat on the following day, I need a day to rest.
What do you do if you ride a day and rest the next? Is it more sensible to increase your caloric intake to, in this example, 2600 daily, or would you alternate between 3200 and 2000?
I am not trying to lose weight. More importantly, I'm hoping to avoid that the caloric deficit would come from losing muscles.
If you choose option 1 (a regular diet), where does the deficit on the training days come from?
If you choose option 2 (an irregular diet), is the human digestive system able to handle the stress of this fluctuation? Or is the secret really to drop the quality of the food and eat, say, cakes or chocolate bars, and then a thousand extra calories become a small volume of food. In that case it seems a spreadsheet would be necessary—to avoid that the outlandish number of calories do not come with an equally spectacular amount of saturated fats. Few would complain of the opportunity to indulge in extra slices of cakes and chocolate bars. The trouble then is the accompanying (saturated) fat. Even if it's not the objective, one of the nice side effects of a workout is to develop a larger heart muscle and larger-flow arteries. It doesn't help if that happens while both become surrounded with fat deposits.
Update

Part of the problem is fear that my hunger triggers may be entirely off. They only signal a very slight extra hunger on riding days, which may mean a slow, inadvertent, and gradual muscle loss. The combination of potentially being hard to measure (slow) yet cumulative (gradual) muscle loss is what makes it worrisome.

Judging by the very existence of hitting the wall, it's not that hard to exhaust the carbs stored in the body. I understand that these carb stores increase with exercise, but meanwhile what mechanism does the body use to average out? Are fat stores really capable of building up and getting used in a short-scale cycle?

Either is fine - in fact on this timescale there's not much difference.
My suggestion:
I suspect that what's most satisfying for your body and your desire to measure will be somewhere between the two - probably something like 2300 Cal on your off days and 2900 on your riding days.  This should be quite achievable - a handful of cheese added to your pasta example and another energy bar on your riding days and you're well on the way.
Reasoning:
The human body is very good at averaging out calories burnt and calories taken in.  This is easily demonstrated: the recovery eating phase lasts several hours (though tapering fast especially regarding glycogen), and carb loading (not needed for up to 90 minute efforts) happens the day before the ride.  You'd see a weight fluctuation if you weighed yourself daily, but that happens anyway and hydration would affect that too.
If you're trying to maintain your weight and muscle mass, with that sort of level of riding, you should be fine with a sensible  balanced diet eaten to hunger - tracking your calorie intake isn't necessary, but if you want to do it, that's fine, except that your estimate of your requirements may not be perfect.
Your body can store enough glycogen for that much effort, so losing muscle mass to fuel your rides really isn't an issue, especially as you're snacking.  If you're worried, some small protein intake during/after the ride would do no harm (even just the little bit you get from energy bars with nuts in, for example).  I sometimes do a 75 minute early morning fasted ride (32km, just under 800  Cal which seems like a good estimate - yours seems high but not implausibly so).  In that case I start a protein drink towards the end, which seems to help my recovery in terms of muscle fatigue/aches.
I take your uneven pattern much further - every couple of weeks I do an all-day or even all-weekend ride, and then you really can't take in what you burn (Strava says 8000 Cal for Saturday's 400km).  The excess hunger lasts 1-3 days, but my weight recovers in a similar timescale (when I first started distance riding there was a permanent drop after each long ride, but as I didn't get weaker in the gym I don't think it came from muscles).  Yes there's some energy-dense junk food in there, but that's optional; I happen to like chocolate.
As for your worry about the stress of fluctuating intake - yes, it's fine.  Most of our human ancestors had no choice (could they afford much more than rice/potatoes/bread every day, with meat once a week - or what could they gather in season, how often did they hunt successfully) and anyway couldn't measure their calorie intake.  Your bowel movements might settle into a new pattern, but I wouldn't expect so much as a mild stomach ache


Low heart rate on climb After trying the local "Hill" I was surprised to see my heart rate dropped substantially despite subjectively putting in a lot of effort. How can I maintain constant cardiovascular effort to all the way to the top of the hill?

I'm a moderately fit, mid-forties man.  I'm in my local running club, I parkrun 5k in 23min etc. I ride to work daily (about 4miles along a disused railway path).
While I'm furloughed, I've been trying to maintain fitness on my bike by doing some longer rides
and up the local Hill, nicknamed "The Wall" on Ashdown forest, Sussex, about 1.5km with a gradient between 8 and 10. I monitor my HR with a Polar 200 watch.

And I've found it pretty tough!

That wasn't a big surprise, but I was surprised to see that my heart rate dropped substantially during the climb from about 140 to about 90-95 on the second (steeper) section of the climb.  A HR of 95 would normally be "brisk walk" level of effort. But subjectively it felt "very hard" with burning legs and heavy breathing. I found it necessary to drop right down to the lowest gear to keep going.

Is this drop in HR expected? What should I be doing to ensure that I am able to push consistently all the way to the top?

My ultimate goal would be "build CV health", but my medium-term motivational goal is "get up The Wall as quickly as possible."

The research I've done such as https://www.cyclingweekly.com/fitness/training/improve-your-climbing-353501 mostly focusses on "how to lower your heart rate while climbing".

I have seen this effect with several different optical based wrist HRM's. Your HR is not 90, but likely closer to 180. Optical HRM's generally have a longer lag to track changes in the heart rate and sudden jumps can be interpreted by the software as drops rather than increases.

I've found that for long sustained efforts, the HRM eventually tracks back to the correct value, but can be wildly off for shorter efforts. There is also the physiological lag in HR vs effort. Early on in a workout, your HR doesn't track your effort particularly well.

Many of the coaching/training blogs I follow are suggesting that perceived effort should always trump HR based training, particularly as HRM's struggle to track correctly at high heart rates. If you're breathing heavy and think you're working hard, you're working hard regardless of what the HRM says.

For a recreational athlete I'd suggest just living with it. I find the convenience of wrist based optical sensors far outweighs the occasional data inaccuracy. Most professional bike riders still use electrical chest based straps for this reason, but they also all use power meters to gauge their efforts during training.

If you want to learn more about the limitations of your device, I recommend searching for reviews on DCRainmaker.


Can I install a disc-brake pannier rack on a bike with V-brakes? I have a MTB with V-brakes. 14-15 years old. I want to get a pannier rack. Will a rack suitable for a bike with disc brakes (eg Topeak Super Tourist DX) fit a bike without disc brakes? I’m not sure if I’m going to buy a new bike in the next year which would have disc brakes, so am trying to avoid buying a second rack at a later date.

Disc rack isn't an exact term. It means the rack will probably be a bit wider and make some effort to clear a disc fitted to the rear hub.
Disc model arms are brought on so the rack supports will be less likely to foul a disc :

Vs.

They both are essentially the same thing and the main thing is that new and old frame has the mounting points shown in the image:

If it lacks these then a rack will be more difficult to install. Some new bike frames will not be built to take racks. So buying a disc type rack doesn't guarantee compatibility. However it's more likely to fit.


Do I really need two bikes - one for road cycling and one for daily use? I am a complete newbie into this road cycling hobby thing -  have done about four to five one-day trips and one two-day trips for now so I am getting more into it.

The problem is I don't want to use it for my everyday use,  like cycling to work and the stuff since it is an expensive bike.  Most of the time I would just walk but now I live even further away from where I work I need to cycle (public transport is out of question).

Is it ethical to have two bikes? Is it common among road cyclists?

I don't think that we would all agree on an answer to the question about whether it is ethical to have more than one bike; opinions vary.  Many of us here on this web site have more than one bicycle, so I would say that in many parts of the world, owning more than one bicycle is common.  Many of us joke that the correct number of bikes to own is n + 1, where n is the number currently owned, but we are kidding.  Whether you need a second bike is a question that only you can answer.

Some people only wish to own one bicycle, so they disguise a nice bicycle with a bad paint job to look like a low-quality bicycle.


Chain skipping with new chain and freewheel I've recently (last 6 months) begun riding again after many years away and have begun updating components on my bike (a mid 80s era Fuji).  After replacing the rear wheel and freewheel I developed a problem with the chain slipping.  On a 7 speed freewheel, the 2 highest gears run fine, the 3rd gear slips somewhere between the 10th and 15th turn under load (but not when hand cranked with no load), the 4th gear slips so badly under load that it won't engage (again, I can't repeat this by hand cranking with no load), and gears 5 - 7 work fine.  Thinking that it could be caused by the old chain I replaced it but the same conditions still occur.

Additional information:

All cables have been recently replaced.
The rear derailleur was replaced about 1 month ago.

Any ideas would be greatly appreciated.

Thanks.

You don't say what derailleur and shifter you have, but if they are an indexed Campagnolo system the spacing they're designed for is different in the middle of the cassette to the ends. I had exactly these symptoms with a 10-speed Campagnolo cassette on a SRAM bike.

You will have an array of problems if the mech and shifter's idea of cable pull do not match, particularly with an indexed system.

You will have exactly this problem trying to use any non-7-speed shifter/mech with a 7-speed system.

You can also get these symptoms if the B screw of the derailleur doesn't leave enough clearance between the top jockey wheel and the sprocket on the cassette, but it is more usual for this to affect the easy gears.


Is shift cable protector under bottom bracket on cyclocross bike important? I recently replaced the shifter cables on my cyclocross bike (Specialized Tricross). Both cables run exposed (not in cable housing) under the bottom bracket, through a little screwed-on plastic guide that keeps them in place.

When I removed the old cables, one of them also included a short, maybe 8-10" piece of what I would call protective plastic sheeth that kind of sat within the screwed-on plastic guide, extending for a few inches out either side. It was pretty shredded up and I decided to chuck it.

Now that I'm looking at the new cables (approx 200km riding), I'm wondering if I should have looked for a replacement for that protective sheath.

Is that protective sheath important and should I have replaced it? If so, what is it called?

The image below shows the cables right now, looking straight up at the BB, front of bike towards top of image.

I saw this similar question, but it seems like the OP there did not at any point have the protective sheath I originally had on my bike.

The thinking with them is to protect the contact point from contamination and provide a slick surface, reducing friction. They do achieve that to an extent, especially early in their life.

The problem is when the liner itself starts junking up with grime that can't be easily removed, it will then cause friction problems itself. For this reason, I think going without is fine in many cases.

Some bikes use them to prevent cables from rubbing the frame on painted surfaces, raw carbon, etc. In that case I would not recommend going without.

You can get replacement pieces from inside shift housing. Take a long piece, cut the outer plastic down it longitudinally with a razor, then whip it hard against a hard surface. The wire strands will come apart and you can take the liner out.


Bike won't shift into 2 largest rear cogs (lowest gears) I replaced the rear derailer on my bike after Schwinn sent it to me. The old one had a bent piece.

I can't shift onto the largest 2 rear gears. I set the shifter to the lowest setting, but the chain won't shift onto either of the 2 largest gears.. It looks like the rear derailer isn't aligned straight with the rest of the bike.

In comparing to another similar bike I have that works fine, I can see that the rear derailer on the properly working bike is perfectly aligned compared to the gears.

Update : I just fixed this (thanks to the suggestions) by tightening the tension cable and also by loosening the H Screw (assuming that is what it is called)...it works perfect now..

update 2 : This question seemed to have got a few views and so updating with some additional information.

The first video sent to Pacific cycles

They were awesome and sent the derailleur (I did not know what this part was called earlier) to me and I put in the new derailleur and then asked this question on stack

I sent the question above to Pacific cycles also and they also replied

with the help of folks here and Pacific cycles I was able to fix this
Luckily in my case it was a simple issue

Thanks,

I didn't see the video but if your talking about the last 2 lower gears you may need to loose the tension cable. if its the top 2 big gears then you may need to tighten.

make sure you derailleur is installed correctly. make sure the last pulley lines up at all cogs especially the biggest one, using your hand and pushing this up and down the cassette, make sure it clears.

try to unbolt the cable, back out on the gears with shifter and back out the fine tune barrel adjuster located on cable/derailleur. pedal, then chain should drop to last small cog. then pull cable hand tight and screw bolt back on cable. make any fine tuning with the barrel adjuster when shifting up.

those are some tips from what I would assume...maybe others can help :)


Will these suspensions fit my bike I want to get this suspension

SR Suntour XCR-RL 26inch Suspension Fork. Black, 120mm Travel, Remote Lockout, Disc Brake Only

But I don't know will it for my bike and also what's the difference between hydraulic and Coil suspension.

My bike is the
Falcon Renegade Mens Mountain Bike 19

The main criteria for determining fork fit are:

steerer tube diameter (1" or 1 1/8")
steerer tube length
steerer tube type (threaded or threadless)
wheel size
brake type

Suspension travel can also come into play as the frame was designed for a fork of a given length. Deviating from this length by adding or subtracting suspension travel can affect the handling characteristics. How much it will affect it is a subject of much debate. I think if you stay with 20mm of stock you are most likely ok.

The fork on your bike appears in the photos to be a  1-1/8 inch steerer and at the price point it sells at it is most likely a straight steerer, (some are 1-1/2" at the crown and 1-1/8" at the top). The disc brakes are a match as is the wheel size. The XCR is a step up from the Zoom fork listed as the stock piece for your bike, but it is still considered an entry level fork. As long as you limit it to entry level abuse it should work fine.

The advantage of a spring fork over a rigid fork is you gain some compression dampening. The fork compresses to absorb impacts and vibration. You generally don't get any rebound dampening. The fork will extend at the same rate it compressed. A hydraulic fork can give you controlled compression and controlled  extension.


Why can't I find a comfortable saddle? During the 25+ years of cycling I've done (5,000 - 7,000 miles/yr), I've tried upwards of 75 saddles, yet STILL haven't found one I could call "comfortable."  By now, I know what I want, but can't seem to find it.  Firstly, I don't like any with those cutouts, grooves, love channels, etc., including those really weird ones (SMP, ISM, Adamo, Cobb, SQLabs).  Basically, I'm looking for a "medium" saddle -- another apparent rare commodity these days -- both padding and size-wise (i.e., not a hard, narrow racer, but not a big, soft "comfort" model, either).  As for padding, the closest I've had is a Terry (men's) Fly and (woman's) Butterfly.  Besides not liking the cutouts, the Fly was definitely too narrow, and the BF a bit too wide (and short).  Shape/wide/profile-wise, the closest was a Blackburn Ciento.  Also liked that the rails allowed a more rearward position (for my 91 cm+ inseam), but the padding was some kind of memory foam that I found a little too squishy.  I'm looking for about a 150-155 mm width, a flat profile viewed from the side, but a bit rounded (mainly near the sides) viewed from the back.

Could the problem be related to fit?  I'm in a moderate position (bar 6 cm below saddle, back about 30-degrees above ground when on the hoods).    I've had 5 bike fittings done, none of which I could call "comfortable" or "efficient."  Most had the bar 3 - 5 cm further away and/or lower than what I have now -- apparently thinking my position was too scrunched up -- which not only caused more rear/crotch discomfort/saddle-sore infestations, but also a 20%+ drop in power output.  (The Guru fits used the "Slowtwitch" system which -- for reasons I can't comprehend -- bases bar reach on a percentage of saddle height . . . this puts my reach a 60 cm, which is 6 cm longer than what I have now!)

Could something about my posture be not-quite-right?  On another forum, someone said that I'm "not sitting the right way."  (Not sure in exactly what way he meant that.)

Or, could it just be that my expectations are exceedingly high?  (Yes, I know a saddle is not a waterbed or luxury recliner, but it would be nice ride without any pain/discomfort down there.)

I'd look into a manufacturer that actually makes saddles in different widths, get your sit bones measured, and try one of their recommended saddles.  Keep in mind that there may be a conversion involved.  I rode the wrong width saddle for a year because I assumed that my measurements should match the listed width of the saddle (not true, the company I prefer has a chart and there is basically an offset, ie my 137mm or whichever sitbones actually use a 143mm saddle, not the 135mm one). Here is an example style size chart.

It sounds like you are looking for a particular width, but there wasn't mention of you having your sit bones measured.  If you've done this, but it hasn't worked out for you, I'd be next wondering about abnormal anatomy.  Just like people have different length arms and/or legs occasionally, perhaps your sit bones are not spaced evenly from your midline and you might need to get some inbetween size to accommodate.  There are companies making adjustable width saddles, so that's also something you could look into.


Should I use a Trek Domane SL5 for touring? I am planning for one week/ two weeks long bike touring, mostly on the road with a moderate amount of riding uphill (mainly in Japan).
My weight is around 60kg. All of my touring gear won't exceed 10 Kg of weight.
I am planning to buy a Trek Domane SL5 (because of its endurance characteristic).
I am prioritizing the following facts to consider for a bike for touring:

Comfort for a long ride.
Durability
Budget-friendly but still not outdated.
7~21 days touring

Is it okay to choose a Trek Domane SL5 2021 as a touring bike?

People tour on all kinds of bikes. That said, if you're going to tour on the Domane, you'll need to figure out how you'll be carrying your gear, since (as Argenti mentions in his comment), it doesn't have any mounting points for racks.
There are workarounds for mounting a rack (which come with compromises), and increasingly people are bikepacking—using frame bags, seat bags, and handlebar rolls that mount directly on the bike instead of traditional racks and panniers (which come with a different set of compromises). 10 kg of gear is probably close to the limit of what you could fit in a bikepacking setup.


Where is the best place to carry water (back or bike)? Where do you prefer to carry your water?  I find when I am mountain biking I prefer to carry my water in a hydration pack on my back (easier to rock the bike).  When road biking on flat ground I prefer to have it on the bike.

Where do you keep your water to optimize speed/agility/enjoyment?

Edit: It seems to me that road bikers never use camelbacks.  Is there a reason for this?

Best?  Doesn't seem like there's any one right answer.

Pros for carrying on bike:

Weight is on the bike, not you
Doesn't make your back all sweaty
No adjustments necessary
Generally easier to clean
Easier to choose alternate beverage options (with the right bottle)
Easier to just always have a water bottle on the bike (one less thing to worry about remembering to bring)

Pros for carrying in a hydration pack:

Easier to drink from (so you drink more often in little sips)
Can drink without waiting for smooth riding (don't necessarily need to remove a hand from the handlebars)
Less likely to pick up dirt (cleaner; but see comment about flip-top for bottles)

Seems like the kind of cycling you're doing makes a big difference.  Mountain biking has more dirt and more rough terrain where your water bottle nozzle could pick up trail dirt and be hard to reach down and grab to drink from.  Road biking tends to have plenty of smooth pavement allowing for drinking from a bottle and not as much dirt to worry about.

I mostly ride on the road and generally use a water bottle (or two or three; or a water bottle and a coffee travel mug), but if I'm going for a long ride (especially in hot weather), I'll use the hydration pack (and probably have a bottle in all 3 cages, maybe with juice or something like that in one) just to be sure I keep well-hydrated.


Fixed cup bottom bracket removal I have a square tapered bottom bracket which I am trying to remove but the fixed cup is proving difficult to loosen. The bike is a Peugeout Princeton from the early 90s. I have heard older French bikes are not reverse threaded, would this likely be the case for this bike?

A large vice can be used to clamp the cup and the frame should provide enough leverage, especially since you've almost completely disassembled the bike. Use some penetrating oil from the inside of the BB. Give it some time to seep into the threads. A hair-dryer could be helpful but a hot air gun might damage the paint.
French BBs are usually right/right and on assembly, thread-locker may have been applied to the fixed cup. If the right cup is 35mm, the BB is French. The British standard is either 1.370" or 1.375", according to Sheldon Brown. https://www.sheldonbrown.com/gloss_bo-z.html#bottom
The article also gives suggestion for removal of the fixed cup.


Can I run a 2.5" tyre on a 40mm rim? I am currently running 2.8" 650b bontrager tyres on my MTB, I am finding that my current tyres do not have enough grip. I cannot find an aggressive enough tyre in 2.8", but I wondered about using a 2.5" tyre.

In short, I would like to know if I can use a 40mm rim with 2.5" tyres, will this have any problems or drawbacks?

Thanks in advance.

A slightly narrower tire should be fine in terms of fit on the rim. Check the manufacturer's specifications for compatible rim sizes to be sure.

You will lose some volume and impact absorption of course. A narrower tire will have a narrower contact patch so you many find that this decreases grip.


Little rear rotor clearance I have just test fit my wheel on a Litespeed T5gravel that I'm building and I see there is less than 1mm of clearance between the rear rotor and the chain stay. The rotor is currently a 160mm avid Centerline, and I'd happily move to a 140 but from what I can tell you can't go down a size with this frame (the brake mount is part of the frame and seems to be built for 160).

Maybe it is fine but it is so close it seems like it will start rubbing even from thermal expansion. See the pic for what I'm talking about.

Any advice?

I think that will be okay.  Have a look if there are no spacers behind the rotor mount bolts - or if it's center lock see if there is a spacer behind it as well.

Removing these may help.


Chain falls off upper pulley when backpedalling I just found out that indexed shifters required mated cassettes, and I am using the rear wheel and cassette from an indexed setup with a non-indexed rear derailleur.  I noticed backpedalling sometimes results in the upper pulley going askew as pictured, and always happens during an upshift.  I never had this problem with my indexed setup.

I have two questions:

I understand simultaneously backpedalling and upshifting is bad, but does the chain falling off the pulley the expected outcome of doing that?
Is it okay to use a cassette from an indexed shifter from a 1990 shimano 105 with a non-indexed shifter like a 1996 suntour cyclone.

I've read the the very similar problem and I included a shot of the teeth of the upper pulley in case that might be the problem.  Also, when the chain does go askew, I don't really feel the difference (I'm not a particularly distinguishing rider).

Yes, chain falling off the pulley is expected. When you backpedal, the chain is moving from rear cog to pulley and you are moving the pulley away from the incoming chain. Don't do that. The pulley is by the way really worn, replacing it might improve things.
It should work, but you need to be very precise with the shifter.


How does a double-headed bicycle pump work I have a pump with a presta fitting on one side and a schrader fitting on the other side. If I leave the pump unattached to anything and work the handle, air squirts out both orifices. But if I put my thumb gently over either hole, the pump pressurizes on the side closed by my thumb and no longer squirts out the still-open side. How does this work?

Note 1: This is a double sided head on a stand pump. There is a selection lever but the effect is there without pushing the lever to either side.

Note 2: There is no need to push a valve into the pump head to see the effect. Blocking a hole by putting a flat cover gently over its outer surface is sufficient.

Note 3: I first noticed this effect when pumping a completely empty tube (outside of a tyre) up from flat. With the valve firmly in the nozzle, and the lever on the correct side, the air insisted on rushing out the wrong (open) side of the pump head. Only when I pressed the tyre rubber almost flat against the inside of the valve, did it build up pressure on the 'right' side and allowed a little air into the tube. That was then sufficient to pressurize the valve so it then pumped all the air out the 'right' side on subsequent strokes.

A small piston or diaphragm is centered by a light spring when pressure is equal and this allows a little air passage opening exposed on both sides. Any pressure imbalance causes the the mechanism to move slightly to one side which closes the low pressure passage and fully opens the passage on the high pressure side.
In physics and engineering this is called an unstable system, a small change cascades to a large change.
The empty tube issue was because the pressure difference was less than the centering-spring preload.
The mechanism could also be a ball rather than piston or diaphragm. Same basic concept as the piston but it uses a ball to close a hole on the low pressure side. In this case more air volume escapes from the open side so the ball gets blown over to that side and plugs the hole which causes pressure to build on the closed side and keeps the ball in place.

It is actually a pretty clever bit of kit, simple, reliable, easy to manufacture.


Resistance in rear hub? I bought a new mid-range hybrid bike (Pinnacle Lithium), and for the first couple of weeks it was an absolute pleasure to ride. Then I went on holiday for two weeks, leaving it in a shed in the heat (if it's relevant). When I came back, it felt like the bike has slowed down. I'm pretty sure it did, because I have another bike that I still ride on the same set of gears, whereas with this one, I kind of went down from speed 6 to speed 3-4 at the back on the average ride.

It feels like some mild, but noticeable resistance on both pedalling and the free ride. I've checked that the brakes don't touch the rims, re-lubricated the chain, made sure the tyre pressure is ok - the problem is still there.

Could it be something like overtightened bearings in the rear hub or grease drying up there? Please tell me I'm not just imagining it :)

Hold the wheel off the ground.

Spin it.

See how quickly it slows down.

Compare to the front wheel. If it's the same then "you're imagining it".

Make sure you have more than 50psi tyre pressure (20psi and it will feel like treacle)

Next time spend some of your holiday outside of bars and restaurants.


Why do my tubes fail with a small area of rubber missing? My last three punctures weren't punctures at all (ie not a flint or thorn) but each time i looked at the tube it was like a small area of rubber had been rubbed away or just fell off. These are continental tubes. What could i be doing wrong when putting new tubes in? I always check the inside of the tyre too! The most recent case was a slow puncture, but the two before that were pretty quick.

It sounds like either something is rubbing a hole in the tube or it's a defective tube.

If it's a wear hole you might be able to locate what caused the wear hole.
Your wear point was either the tire, rim, or sometimes a tube gets folded and wears against itself.

I always put my tubes and tubes on so that the pressure rating on the tire is above the valve stem and on the freewheel side of the rear wheel or on the non-lever side for the front wheel. Doing this makes it easy to find pressure ratings and it allows me to more easily find where a hole in my tube came from.

Even if you don't know exactly how the tube was laying inside the tire looking at the hole in the tube in relation to the valve stem can help you find the wear spot.

Finding a rim wear point
If the hole is on the valve side of the tube in the narrow band that contacts the rim you can put the tube back on the rim and line up the hole with the rim to find the wear point. The wear point would be in one of two spots on either side of the valve hole in the rim. Look for something about the rim that might cause wear and correct it. Everything should be smooth and abrasion free.

Finding a tire wear point
If you know how the tube sat in the tire - because you put it on a specific way or because you remember then trace the hole back to the tire and look for a rough spot or something that could cause wear.
If you don't know how the tire sat in the tube feel around inside the tire and make sure everything is smooth. Be sure to check the inside of the tire bead.

Folded tube
If the hole is due to the tube rubbing on itself there are sometimes fold marks on the tube around the hole. When installing a tube make sure that it lies smoothly inside the tire with no creases or folds.

Defective tube
If the tube is defective it will look like the tube material gets thinner around the hole or the seam is thinner than the rest of the material. If the hole looks rubbed or abraded then it's not a defect. Your local bike shop should have someone with an experienced eye who can identify defects.


Suggestion on buying a single speed 29er mountain bike I'm interested in buying a single speed mountain bike for about $400-600. Can anyone recommend me one?

I tried buying this http://www.redlinebicycles.com/bikes/mtb/2012-monocog-29er but it is all sold out. I'm 5'6" so I need a small frame for a 29er. I would like the bike to be in a darker color like in the link if possible. Nothing like white or bright colors on the bike as it's main color.

SE Stout is a single speed mountain bike that runs relatively cheap.

If you're confident in your ability to put it together properly, you can find them at bikesdirect for around 350.
http://www.bikesdirect.com/products/se/stout.htm

It's got tabs for disc brakes so you could upgrade in the future, but comes with V-Brakes stock.  I have a few friends who have these bikes and really like them.


Can I replace post mount disc brakes calipers with flat mount calipers? I have post mount TRP Spyre calipers, how can I upgrade to flat mount Ultegra calipers? are there adapters available? I've only seen adapters for flat to post.

I think there are no adapters on the market to use flat-mount calipers on a post mount fork, so your options are:

Get a flat mount fork and Ultegra caliper you want. I actually did that, the additional price will depend on new/secondhand and no-name/open mold/brand name factors.
Get any post mount Shimano hydraulic caliper, those are all compatible. There's no actual Ultegra post mount calipers, but prior to R8000, Shimano made a non-group, Ultegra-level ST-RS685/BR-RS785 shifters/calipers, so you might use a BR-RS785 or slightly older BR-R785 (actually an XT).


How do I remove rust from my seat tube? I just pulled my seat out as the first step of breaking my bike down for winter storage, and found that rust has formed between my seat tube and my seat post. The rust starts maybe 3" down the tube and continues for perhaps 4 more inches.

Is there anything I can do to remove the rust from the tube and post? What steps can I take to prevent it from reforming?

You can probably use a small wire brush to get the rust out of the frame and for the future use JP Weigle Frame Saver spray. It acts as a rust inhibitor so should slow down/stop any rust forming on the inside of the frame. You can get frame saver at JensenUSA (I'm sure there are lots of other spots too).


What is the difference between a road bicycle tire size 700 x 23c and I 700 x 23 I've been riding road bikes for years but really wasn't too aware that there appear to be two different tire sizes, for example a 23C and a 23. ( 700 x 23. And 700 x 23c )

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


How should I train for gravel rallies? I would like to start riding gravel rally events like these:

http://www.dirtyboar.be/

https://www.dirtyreiver.co.uk/

So far the maximum I did like this was about 3 days doing 60 km a day on similar terrain. I feel I could have done more, but not 100% sure on how I would end up if I did 200 km straight.

So my question is, how should one train for these kind of events before signing up?

I suggest given your goals (finish and enjoy) you can train for fitness largely on road, but try to get out and train on gravel whenever you can.

I've had some fun on my tourer on gravel tracks recently and can say that it's well worth getting in some practice on that surface, in a range of conditions -- the bike will handle very differently.  You should choose your gravel tyres soon and use them for practice (there's no real harm in leaving them on for on-road training in your case).

Luckily your goals are compatible with not having much chance to ride the course in advance, as it looks like you're planning to travel to at least one of the events. Also the Dirty Boar doesn't permit riding in advance as they've got special permission for some of the route.

In your position I could be quite tempted to sign up for the 130km version and just go for it with only enough specific training to try out your gravel tyres (and bike?) on gravel.


Can I replace a GXP press fit bottom bracket with a Hollowtech? I've recently acquired a frame for a project and have an Ultegra crank set from my crash bike I want to use on it.

The frame currently has a GXP 24mm press fit BB and I've got a spare Hollowtech BB, a Shimano BB-R60 threaded unit. Can I replace the press fit one with the Hollowtech?

You cannot fit a threaded bottom bracket into a press-fit shell frame. A threaded Hollowtech II BB for road cranks will only fit in ISO threaded bottom bracket shell of width 68mm.

GXP is a crank axle standard not a BB standard, so that does not tell us what the press fit cups in the shell are. What you need to do is measure the cup diameter and shell with. Look up what BB shell standard you have (easy to find on the Internet). Then find a BB that adapts between the frame and Uletgra crank.

With any luck you will have a BB86 frame (41mm cups, 86mm wide) - that's the Shimano press-fit standard and sometimes know as Hollowtech press fit (it's the same axle dimensions as a threaded Hollowtech BB). I believe road GXP is also 86mm wide so it seems likely. if you have a shell with larger cups designed to accommodate 30mm axles there are adapters available.


Cannot fit wheel into dropouts I recently bought a wheelset that supports 11sp and 10sp casettes. The wheelset came with a 2ish mm spacer. I have previously owned a 10sp wheelset that had a 1mm spacer.
I have been told that for 10 speed cassettes I'd need both spacers on the new wheelset, so I put both of them on.
It worked for a while until the wheelset developed some (unrelated to this issue) noise so I took it off the bike, but then I  had serious trouble getting the wheel back into the dropout.

Not only did the new wheelset with the spacers not fit into the dropouts, the alignment of the wheelset was off and I couldnt even turn the wheel because it was rubbing the chainstay.
The old wheelset without the casette on the other hand would fit just fine so I thought something was wrong with the new wheelset and sent it back.
Now I wanted to put the old wheelset (which is my trainer wheelset) back on with the casette and only the 1mm spacer.
The problem is that much like the new wheelset I couldn't event get the old wheel into the dropout, so I took out the spacer and it fit first try.
I've used the old wheelset with the spacer in the past and I'm not sure not what I'm doing wrong.
The new (already sent back) wheelset had other issues, but I want to know:
Does this issue indicate a bigger problem with the bike or will I be fine without the spacers ?
What spacers do I need to use with 10sp or 11sp wheelsets ?
What could be causing these problems ?

I have made sure that the length of the hub is compatible with my frame, so that should be not an issue.

You need enough spacers behind the cassette so that when you tighten the cassette lockring there is no play of the cassette on the freehub. Probably 0 on 10 speed freehub, at least 1mm for 10s on 11s FH. The cassette shouldn't touch the frame in either case, so having a spacer shouldn't have prevented you installing the wheel or cause misalignment. If it was the cassette touching the frame that stopped you mounting either wheel there might be scratches to evidence this but it seems unlikely.

As commented, check that the wheel fits without the cassette fitted at all. Also check that the axle locknuts are tight (i.e. that you can't unscrew anything from the axle with your fingers). Check that there is an even length of threaded axle exposed on both ends (roughly 4-5 mm).

The most likely suspects in my experience, however, are the springs on the quick release skewer. Presumably you have had to remove the skewer to change cassette spacers. If you put either of these on backwards then they can obstruct the axle entering the dropouts at all, and will cause the wheel to be out of alignment if it does go in, maybe causing tyre rubbing on the chain stay. The springs have a narrow end and a wide end and the wide end goes on the outside on each side. The spring never sits over the threaded axle. There's a picture on http://bicycletutor.com/remove-install-wheels/
If you were doing this correctly all along then I'm all out but this might help someone else


Shimano ultegra 11-28 to 12-32 options? I have a Shimano Ultegra RD-6700 rear derailleur with a 10 speed Shimano 105 5700 11-28 cassette and Shimano R565, 50/34 (compact) up front.

I would really like a larger gear for climbing. Can I go to a cassette with a larger than 28t that would not require a new derailleur?

I see that in Shimano 105 5700 cassette series only goes up to 11-28,
but the Ultegra 6700 10 speed goes to 12-30. Is there another cassette that I could use that goes to -32t?

How can I tell if I have the RD-6700-SS (capacity 33t) or the RD-6700-GS that has the 39t capacity? It only has "Shimano RD-6700 Japan VIA" stamped on the back. It's the one that came with my 2013 Trek Madone 4.5.

I assume that I have to stick with a 10 speed cassette in any case. Are there any options beside the Ultegra 6700 12-30 that would fit?

Any advice is greatly appreciated!

EDIT: I measured the distance between the centers of the jockey wheels, and its about 6cm, so it looks like I do have the short version.

Is it possible to go from a 10 speed to an 11 speed cassette, like the Shimano Ultegra 6800 11-32, without changing the shifter? I realize that I would have to change the rear D to something like the Shimano Ultegra 6800 GS, which says it can handle up to an 11-32.

I didn't see any options for changing the the front chainrings, it seems like the 50/34 compact is the only one that fits this bike.

To use older 10-speed Shimano shifters such as Ultegra 6700 with cassettes larger than 28t, you need to use a 9-speed MTB derailleur.  You'll be able to handle cassettes up to the largest specified for the MTB derailleur (and likely a bit larger).

Shifting won't be as good as a full Ultegra 6700 drive train, but it will work.


Tubular tyres on carbon tri bike I have a full ironman scheduled in 2018 and will therefore be doing a lot of mileage next year. My question is, if I get a flat during the race, is it basically race over as it is unlikely that I or mechanic will be able to fix
at roadside or is there a quick fix solution to get me to the end of the 180k race?  PS - I am a female and not good at changing tyres quickly at the best of times

It is a matter of personal preference.  Triathlons generally have to be self supported (with some exceptions) so getting a full wheel swap like in Pro Bike races is not an option.  I run clinchers mainly for this reason as they are easier (for me) to swap out on the side of the road.  However, depending on your rim/tire this can still be pretty tough sometimes.

So if you are running tubs you would have 2 options:

Carry a spare tub tire & CO2.  You would need to be able to peel off the old tire, re-seat the new one, and re-inflate. This can be pretty hard.  Also, usually when you glue on new tubs at home you use fresh glue and let then set awhile to make sure they are well  adhered.  However, in this case on the side of the road you will be re-using the old glue or you could try tube tape (never used it personally).  This is a bit dangerous as now your tire is not as secure onto the rim and you risk "rolling" it off in hard cornering ...
Carry a sealant like Vittoria Pit-Stop.  This might seal & re-inflate your tire but if it doesn't then you are out of luck.


Does the plastic cap on a Presta valve serve any purpose once fitted to a rim? I can see the use of the valve cap on a Presta valve when the tube is still packaged (it obviously stops the valve puncturing the tube), but does it do anything except look pretty (or not) once you've fitted the tube to a rim?

I've kept them on out of habit, because I've had problems with sticking Schrader valves in the past when I've lost the caps and dirt/grime has got in there - but the design of Presta valves suggests to me that they wouldn't suffer this fate.

Given that I really need to inflate tyres on a road bike every day, is replacing this cap something I can leave out of my daily chores?

The cap keeps dirt and rocks away from the valve, particularly the fragile release mechanism. It's not the end of the world if the caps are missing, but I suggest leaving them on. They don't take that long to remove and replace.


Sun protection clothing I would like to see if there is clothing that can provide sun protection while
minimizing sweating and/or allow air flow.

Would also like to do the same with my bike helmet without compromising safety.

Ideas?

Many items of quality cycling clothing from reputable brands with high SPF are available. Under-helmet caps with the sun protection are available as well.

Since this site doesn't do product recommendations you'll need to browse producer and retailer sites.


Why are disc wheels not used in the front on professional track sprint races? Why are they used only in the back if there is no risk of winds at all?

Because it's not permitted under UCI regulations.

Rule 1.3.018 applies, which includes this section:

  In track competition, including motor-pacing, the use of a front disc wheel is only permitted in the specialities against the clock.

Disc wheels are commonly used in the sprint qualifying round (i.e. the flying 200 metre TT).


if my height is 5'9" what mtb should I buy? I am rookie and I want to know about mountain bike and want to know that if my height is 5.9 which mountain bike works for me. So guys please help to know about mountain bike.

This is impossible to determine via the internet - the fit of a bike depends on inseam, arm length, and a multitude of other physical measurements as well as personal preference and the type of bike (there are large variations in types of mountain bikes even) and riding style.

Read this article and this article for more details on what goes into bike fitting. Note that its really more of an art than a science.

Go to your local bike shop and ask for a bike fit and try out lots of bikes in realistic riding conditions and find one that works for you.


Do I need to use thread locker or spoke prep when building wheels if spokes come pre-treated? I purchased a dynamo hub, rim, and spokes for a wheel build. Unknown to me at the time of purchase, I discovered that the spokes all have blue thread locker compound pre-applied to the threads.  The spokes are DT Swiss Competition.

1) Do I need to use any other thread-locker or spoke prep?

2) Do I need to lace and tension the wheel all at once, or can I lace it one day, set the nipples to a set start position (with a nipple driver) and then tension it later?

DT Swiss make a series of spokes called ProLock which incorporate a re-usable thread-lock type feature. You can build these over several days no problem and re-true them for years without trouble. It isn't blue, so that isn't what you have.

The usual blue stuff is Loctite 242 which I would not personally want to use on spokes because it sets in ten minutes and is fully cured after 24 hours; after it cures you can fully break it apart but not make small adjustments, so later truing will not really work. Should you wish to remove it Loctite's data sheet suggests the correct solvent to use is methylene chloride.

I personally use grease on spoke threads, as on any other threads which don't need locking. With grease or ProLock you can take as long as you like. I never tried Spoke Prep for lack of a UK supplier at a reasonable price.


First time ride advice Doing 75 km "Ride For Heart" in Toronto this Sunday on a closed highway.
Using Norco Cyclocross bike for it.
I've read online different advice for beginners, but was wondering if there is anything else the community can suggest.

Be polite and communicate intent with other riders
Cadence ~ 70-80 rpm
Drink/Eat a bit throughout the race not to reach the state of bonking and dehydration
Have fun :)

Am I missing anything important?

Update:
Thank you all for the advice. The ride went well and we finished in about 3.5 - 4 hours.  Avg Speed was ~20 km/h. Highest recorded - 37.5 km/h :)
I don't know how to pick the "approved" response because many people contributed very helpful info.

With respect to riding in a group, or with more numerous riders closer to you than you are used to.

Be aware of the space around you
Maintain a safe distance from riders in front
Look sideways and over your shoulders before overtaking or maneuvering
When cornering be aware of riders to you sides and give them space
When slowing down, hold up a hand palm forward, or call out 'slowing' or 'stopping'

Common sense stuff really.


Graber bike rack installation on Honda Accord I have Graber 2 bike rack.
While installing I noted top narrow side of Graber arm rest on top of the trunk and bottom wide arm rest on rear bumper.

How safe it is to carry bikes like this ?
If Bumper strong enough to hold 2 bike weight ?
Note that car is 17 years old.

Thank you,
V

When properly installed these type of trunk mounted racks do not actually rest on the bumper.

The lower arm should be positioned slightly above the bumper and bottom edge of the vertical part of the trunk lid. The weight of the rack and bikes is actually supported by the top straps.

See the pictures at the Graber web site (not sure if it's exactly the same product, but it shows proper installation.)

https://www.graberproducts.com/product/guardian-elite-2


Gravel road bike fit Looking at gravel racing what should I look for in fit compared to a normal road bike setup? I'm concerned about stack and reach angles of head tube and seat tube, bottom bracket drop, fork rake and such things.

"Road Bike" is a pretty broad term, but let's assume we're talking about a bike designed for long-distance road riding and not criterium or even road racing—a category used to be called "sport touring," but is now referred to as "endurance racing." Current examples include bikes like the Trek Domane, Giant Defy and Specialized Roubaix.

Also, it depends somewhat upon what you mean by "gravel racing." If you're referring to short events like Barry Roubaix that are at most a couple of hours, then a cyclocross bike would fit the bill as well as anything, especially if you already own one. The downside of using a cyclocross bike is that most are really designed for short, fast, off-road races and don't necessarily lend themselves well to all-day comfort or long, 40-mph descents.

There are a few cyclocross bikes that are designed to be less aggressive, and those are the ones that tend to turn up at gravel events. Current examples include the Trek Cronos and Boone, and the Surly Cross Check. The Niner RLT9 is marketed as a gravel bike but has a design that fits better into this category. My experience with this class of bike is that they require more effort to arrive at a good fit, and can feel more exciting than necessary on fast downhills.

"Gravel" bikes aren't all alike either, but the ones that are different than cyclocross bikes feature a longer head tube (for more upright riding position), lower bottom bracket, more fork offset and slacker angles. The best current example is the Raleigh Tamland, but the All-City Space Horse is pretty close too, despite not being marketed as a gravel bike.

To me, the best thing about "gravel" bikes coming into style is that they're actually good for a very wide variety of surfaces and emphasize comfort over raciness. Not limiting a ride to one specific type of road opens up a lot more riding opportunity.


Kalkhoff Agattu (e-bike) Panasonic 24v engine dead - worth repairing? UPDATE:

http://www.kalkhoff-bikes.com/en/bikes/e-bike/e-activity/agattu-impulse-8-hs-8-g-1.html

I went with one of the above. It's not a 2016 model though. The Impulse 2 drive is awesome.

My three year old Panasonic crank engine just gave up the ghost recently.

The dealer says that the engine shorted the battery and vice versa. So I'd need both components as new or used.

The battery costs 600EUR or less depending on capacity.
http://www.amazon.de/Derby-Panasonic-Motoren-Kalkhoff-Ladegerät/dp/B007GBD8RS/ref=sr_1_1?ie=UTF8&qid=1450190851&sr=8-1&keywords=e-bike+batterie+24v+panasonic

The engine I could not find at a glance.

So my question is. Do you think it is worthwhile for me to try to fix the electronics of the engine / replace the battery of a 3 Year old bike that was used daily for climbing hills. Or rather just get a new bike that costs 2600,-EUR with newer technology. Impulse 2 system from Kalkhoff.

And would it make sense to remove the engine and use the bike as a non e-bike instead?

Update:

Just to clarify the battery seems to be charging fine in the charger. Pressing the check charge button works as usual. Only when the battery is in the bike, pressing the check charge button makes all charge lights on the battery flash in sync. So I do think the electronics on the engine are gone.

Also:

              this looks like the motor and the electronics are one part that can be swapped.

So the question is, do I want a brand new bike with brand new technology or refurbish a well worn 3 Year old bike with an aluminum frame  that had several falls, lot's of pot holes and one accident running from behind into a car.

Since aluminum does tend to just break without much of notice I'd rather go with a new bike even though it is a heavy investment. The e-motor on the new one and the whole riding experience is superb.

First up - I know nothing about your specific bike model.  However 3 years is a pretty good run for batteries especially if used for hill climbing, and it could be they're just past it and need replacing.

600 euros sounds a lot, but its one of the consumables.  Do you know how far you're ridden?  10,000 km would be 0.06 euros per km, which is a lot cheaper than a car.

Its highly unlikely the battery shorted the motor and the motor shorted the battery killing both.

If you're handy, try and find two working 12V batteries (car ones would do) and hook them up in series to the leads, with your powered wheel off the ground.  Do mind the polarity and watch for shorting.  The bike should run like normal on 24V.  For this test, battery type doesn't matter but current will need to be at least 10 amps so small batteries are unsuitable. If this works, the motor is fine.  You might be able to use a mains PSU adapter, provided it supplies 24V DC at 10-15 Amps.

If this doesn't work, the motor or controller may be damaged and you need some more skilled local help.  Google about for an ebike retailer or specialist in your region.

Best to google about for a replacement battery pack or find a battery specialist who can repack your existing battery.

A bike is not a cellphone to be replaced every couple of years, with normal maintenance it should last for decades.


Choosing good slick tires for a MTB I have an MTB with tires that roll very poorly on pavement because of the thread lugs. I'm looking to get a pair of slicks and I'm hoping to get some advice here. My bike is a 29", I think they current tires are 700c 2.0" so I'm looking for something between 35c to 45c? What's the difference from choosing 35c vs 45c? Will it go faster on 35c and can I expect some difference in handling of the bike?
Would it be better to buy some new wheels than 2.0? Any advice on optimal tires for such a bike?

Since you have 700C/ISO-622 rims and you're doing pavement riding, I'd recommend one of the Conti "Gatorskin" tires. They go up to 32mm wide-- which is nearly optimal for urban street riding and nicely adequate for occasional trails w/o mud.

These are very popular as training tires for roadies (in narrower widths) because they're very resistant to flats caused by glass.

Handling will be different in "feel", but nothing that you can't get used to in 10 minutes of riding.


what could be the reason for very inacurate strava tracks of my bike excursions? I'm not sure if this is the right "forum" to ask the question but I'll try anyway.
So I'm using strava to log my biking excursions. Recently I have noticed that my recorded tracks are very "ugly" - lots of straight lines across several roads and buildings, lots of zigzags and loops.
What could be the reason? I thought that some apps are disturbing gps but the same happens when I kill all the apps. GPS track from my garmin, if both are turned on at the same time, looks much better.
it was not so before, btw.

GPS units have variable performance for a number of reasons

Bad satellite position - Simply put, all the satellites transmit "bing!" at exactly the same time.  Your received deals with the differences in the time between reception of each signal.  So the most accurate point will be calculated if the satellites are distributed over the sky.  If all the visible satellites are in the same quarter of the sky, you get a larger possible location, or one with more possible variance.
Urban Valley, regular valley and multipath - if you're in an area with big hills, or tall buildings, or sometimes even very wet trees the signal can be attenuated, slowed, or reflected.  If the signal is slowed by even 0.001% then that's 22 kilometres of variance, (assuming satellite orbits at 22,000 km.  This can be mitigated somewhat by putting your phone in a toptube bag rather than deep in your pocket.

I carry a folded thermal space blanket made of foil when on long rides, and it messes with the phone terribly if they're in the same pocket.  Doesn't matter which is on top.  Also if your clothing has a metallic weave this can interfere with transmission reception too.

Fudge factor - Some GPS, and the Strava app are known for "slewing" results.  They've used the last N seconds as an input to calculate the next point.

Here's an example.  Notice entering on the left at fairly decent speed, probably high 30 km/h.  The path slews out into the river, and then winds its way back to the road.   I have seen far worse at this corner but this was all I could find in a brief search.  I do this segment frequently.

Broken antenna/aerial(s)  Your GPS is on a bike and suffers a lot of vibration.  If the signal is not received clearly then that could add delays which impact processing, or could drop one/some of the time pulses from the satellites increasing error
Lagged CPU.  Historically a GPS was a standalone device with dedicated chips for calculating everything.  If you're using a smartphone, there will be dedicated GPU circuitry but it will still need time on the main CPU to do stuff.  If its busy playing songs and whatever else, then that could also delay the processing of point data.
Your speed - If you're going fast enough, minor discrepancies can multiply out to larger errors.   50 km/h is almost 14 metres per second, so a second's lag puts you out by 14 metres.

I'm not familiar with Garmins, but they're single purpose units and are unlikely to suffer CPU starvation. (other than garmin's rear-facing radar whatsits.)

That's all the causes I can think up now.

Solutions

The best solution is to tweak your strava recording using SNAP (strava needs a polish)   However I've noticed this site has become increasingly harder to get to.

When it does work, you can load your activity from strava, push the lines back onto the road, and it will create you a GPX file to download.

Then you upload that fixed file to strava and once its looking better you can delete the original ride.  Do it in that order for safety, I've lost one big ride by getting it wrong.

Second option is to use your garmin to to the logging and leave the cellphone recording as a backup, deleting the worst once once you return home.


Professional bike mechanics & maintenance training courses Recently I have been doing some small fixes in own bikes, I have enjoyed it a lot, then comes to my mind the idea that would be nice to help others as well, but in a more professional way.
What is the most professional training one could take to become a bicycle technician?

Since you’ve stated in a comment that you live in Austria, I think the only specialised education for bicycle mechanics in Austria is an apprenticeship: https://www.berufslexikon.at/berufe/2898-FahrradmechanikerIn/ (Austrian job encyclopaedia)
In practice I think what matters most is experience (and of course taking your time, checking things, following proper procedures etc.). An education in mechanics, engineering or even physics helps a bit for basic understanding, but in the end there is no way around experience. You could get that by either owning and maintaining a lot of bicycles, working at a bicycle shop or volunteering at free bike repair events (here in Linz there is one in a week).
A bicycle is a very simple machine but there are tons of different components and compatibility is always a problem. Having all the right tools can also be difficult.


Noise between Seat Tube and Top Tube I bought a Trek X-Caliber 9, September last year.
About a month ago it started to do a very annoying sound between the welded junction of the Seat Tube and the Top Tube.

What I have tried:

Switch the seat post and saddle.
Switch the pedals.

I cannot ride with these noises they truly disrupt my mind.

The creaking only shows up when I sit on the saddle, I replaced the saddle and the seat post but the creaking didn't cease. I think the noise is from that area because I've put my hand in there and felt the creaking.
I have cleaned it several times and even if I lower the seat post the creaking continues.

UPDATE: I still have the issue, I am going to the second Bicycle Repair Shop this weekend, But I think it is the left arm crank who's making those noises. But I will keep you updated!   2021-04-23

I suspect that your seatpost is graunching inside the frame as the rider's weight moves about while pedalling.
By inserting the post much further than normal, it will apply a different less-worn part of the post to the clamping area of the bike.  But you've tried this and the noise continues.
So the next cause is that the frame is slogged out already in the clamping area, because of movement of the seatpost and the leverage afforded by the long unsupported length.  You could do the seatpost clamp up tighter, but this is likely to be a short term fix.
Try unclamping the seat post, removing, and then do up the clamp without adjusting it.  Then measure the hole with vernier calipers in multiple directions.  You want to see the same number in all diagonals.  Also feel inside with a finger - it should be flat in-line with the seat tube of the frame, with no detectable curve.
If there's physical damage, you should talk warranty with the seller as soon as possible.
Personally the super-long unsupported seatpost is a recipe for disaster IMO.  I've cracked three frames in decades, and bent multiple seatposts by having them too long and/or too little inside the frame.


What is the measurement in inches of a XL frame? What is the conversion of a (XL) frame to it's measurement in inches?

It depends on the particular frame - XL doesn't mean a specific size. Also, even for frames labeled as the same size number (say 23" or something), thats only one measurement to summarize the size of the bike - there are many more which can make a bike fit or not - top tube length, stand over height, etc.

(Look at all of the quantities labeled on the figure, courtesy of Trek).

The two most important though are top tube length (E) and standover height (B?).


Tyre choice for loose gravel I have a mountain bike that I take out to a local bike trail. Currently I have some thin XC tyres and they don't seem to offer much grip when going at speed. The trail is 80% downhill and mostly loose gravel.

What tyre type would you recommend for loose gravel?

Thanks.

For loose gravel, I believe what you want is big, wide tires that you run at a relatively low pressure.  I don't think knobs will help much.

The wider the tire, the more it will press the loose gravel down instead of pressing through it. If the gravel is pressed down it will tend to stay more in place.  Also, if some of it shifts, a wider tire will be more likely to have grip on something that isn't shifting.

I don't think knobs would help unless the gravel's fine enough that the knobs are larger than the gravel pieces: they'd tend to push the pieces of gravel out of place just as you roll over them, which isn't what you want to have happen.  And unless the gaps between knobs are the size of the gravel pieces or larger the knobs won't really grab onto the gravel pieces, either. Probably don't hurt much, though, especially if they're more to the side of the tread pattern.

Take into account that you'll always have an upper traction limit of the gravel's friction against the gravel under it, which can be quite low, especially with smooth rounded pebbles that can roll over each other.


What does 'campy' mean? What does it mean when people say that a bike part is "campy"?

I've heard people say "campy hub" and "campy chain", for example.


How to determine tyre pressure for trail descents? I ride XC for recreation: trails, dirt roads, gravel roads, some rock beds. The bike has a hard-tail frame with, 80mm travel fork and 2.10 inch tires.
I have noticed that pumping the tires a lot makes riding on asphalt easier, however grip is reduced off-road.
How should I determine the correct pressure of the tires for optimum grip when descending, while still avoiding pinch flats? Can this be expressed as a function of the recommended minimum and maximum pressure? Is it different for the front and rear tire?

Snake bites (i.e pinch flats) depend on tyre strength, tube thickness (in case you use tubes), rider weight, riding style, terain and luck (or unluck). You really need to experiment with the pressures. For example test if 25/30 PSI (front/rear) feels good and see how long you can go with that without a pinch flat. If you get a pinch flat on the rear once a year then I guess you can continue using 25/30. But if you, like me, get them once a week then you definitelly need to increase the pressure. Note that pinch flats usually happen on the rear. In the last 3 years I've had 2 pinch flats on the front and like 20 on the rear.

If in the end of this iterative process you have increased the pressure too much (e.g 45+ PSI) then there is a high possibility that the specific bike and tyres you use are not meant to do what you make them do. i.e you need heavier tyres or more suspension.

Note that if you switch to tubeless you'll be able to run the same PSI and most probably completely avoid pinch flats. Note though that pinch flats are still possible.

Also, make sure you read:

http://www.pinkbike.com/news/Tech-Tuesday-tire-pressure-2011.html
http://www.pinkbike.com/news/To-The-Point-Tire-Pressure-2013.html

For the other specific questions:

Can this be expressed as a function of the recommended minimum and maximum pressure?

No. Also, not many people agree with the min/max numbers. Some people say that the max is a warning to never exceed that and just a number to reach when initially inflating the tyre in order to let it seat correctly. Then you deflate to your desired number.

Is it different for the front and rear tire?

Definitelly. Some people say around 5 PSI more on the rear.


Am I going to do any damage by swapping cassettes frequently? I've got a separate wheelset for cylocross riding and road riding.  Would it be detrimental to the life of my cassette or hubs If I swapped the cassette between my road and off-road wheelset frequently?

The main hazard is that, with so much swapping, you will sooner or later cross-thread the cassette and ruin both cassette and hub.  There will also be additional wear on the threaded surfaces and on the spline, where you wrench it on and off.  The spline may eventually become too worn to allow removal.

So a lot depends on the care you use -- if you get too casual in doing the swap you're apt to muck it up.


Replacing Mechanical Disk Brake cables I am having problems with replacing brake cables on rear wheel. The bicycle has mechanical disks. I removed old cable successfully and I've put the new one in. The thing is that I feel like it's not tight enough, but I cannot tighten it more. When I try using the brake, it doesn't brake at all.

Here are the images:

I didn't cut the cable yet because first I'd like to get it working properly. Do you have any clues on what's wrong? I don't think that I need to adjust the brake, as I am only changing the cable.

The cable should be pulled through the pinch bolt on the brake, making sure any breaks in the housing are seated in housing stops on the frame, until it is tight enough that the arm on the brake is just beyond it's "relaxed" position.  Then tighten that bolt, check that it works, and if it does, leave about 3" of cable coming out of that bolt, trim the excess and install a cable end.  Otherwise, looks like you did a very good job installing a cable, for I'm assuming the first time?


Rockshox Pike Scratch I have a rockshox pike with scratches on the fork stanchion. I would like to know if there was anything I can do without buying a new one. Any suggestions would be greatly appreciated!
Here is a picture:

If it doesn't leak oil or anything, you always have the option of just leaving it as is. "If it ain't broke don't fix it." Otherwise, clear nail polish is an option. You'll want to extremely carefully sand or file the rough edges off.
You can also buy just the upper half of the fork. You don't need to replace the entire thing.


Tire pressure on new bike I have the new Tommaso (was Timmaso) Imola bike with Tommaso Corsa TC20 wheels.  The tire sidewall says "max pressure 90 psi"

The tire is the kenda 700x25c.

I am 5'9" 220 used to be a power-lifter so pretty heavy. Question is can I inflate them to closer to 120 psi due to my weight?

This handy chart shows the recommended pressure for different rider weights.
Sadly it doesn't help you or me, both our weights are off the chart.

My road bike has 700x25 tyres, so I picked 100 PSI and aim for just over that when inflating.  The tyres are rated to 120 but that feels harsh and I get a lot more flats at those pressures.

Added: Since your tyres say maximum pressure of 90 PSI, you shouldn't go much over that.  Kenda's specs say 90 psi is the maximum for the "kenda street black mocha" so while they will survive more, the question is how much more.  Instead, consider replacing them with tyres that are suitable for higher pressures.

Note: This chart is purely referencing road tyre pressures.  If you have a MTB the pressures drop off really quickly.

Answer: I wouldn't go much over 90 PSI, but others have routinely put 100 PSI in Kenda tyres without issue.  Your weight suggests that a higher max-pressure tyre would be the best solution, aim for 120 PSI capable tyres in 28 width.


Replacing 28in wheels with 26in I'm told that when touring (carrying a big load) you're much better off to have 26" wheels than 28". But most second-hand bikes seem to come with 28".

Is it possible to replace the larger 28" wheels with smaller 26" ones?

What sorts of issues would I run into?

pedals hitting the ground?
v brakes not being able to reach tires?
gear/derailleur issues?
etc?

It's possible to put smaller wheels into a bike frame but I can't see why you would want to. Bike frames are designed for a certain size wheel, so putting smaller ones in will affect the handling.

You've already mentioned the brakes not working correctly, which is a fairly major factor. Pedals may or may not hit the ground, but you'd certainly have less ground clearance.

You haven't said why smaller 26" wheels are better. A bike with 26" wheels might be better for what you want to do, but just fitting 26" wheels to a bike made for 28" wheels is not good idea for the reasons above.

K


is biking lower wacker drive in Chicago a good/feasable idea? Not sure if location specific questions are on topic here but, here goes:

I live in Chicago, and I'm curious about biking Lower Wacker Drive. (If you're not from Chicago, it's where the underground scenes were shot in Batman: The Dark Knight). It never seemed like the best idea, but
1. It is easily the most direct route between my house and work and back
2. I do occasionally see bikers on it when I'm driving down there

Specifically I am interested in the chunk between Harrison and Franklin to Lower Michigan and Illinois (which is a fairly large chunk).

Lower Wacker is a multilevel street that runs through downtown along the
Chicago river. Since it's underground, it doesn't intersect with a lot of streets, making it an ideal shortcut through downtown if you know your way around. They don't specifically have a bike lane, but I do see bikers down here from time to time.

The obvious risks are that there is no bike lane; I tend to prefer routes that offer a bike lane, and since there are typically few to 0 bikers down here, drivers are likely not used to looking out for bikers.

Is it a horrible idea to bike here? Is it reasonable if I am paying close attention and taking care to be aware of my surroundings? I would especially value a response from someone who has experience biking down here.

Answer (tl;dr)  Find another route.

I checked around using google street view to get the image in the question.  Some observations...

There are no cyclists visible anywhere.  There are also no motorcyclists I noticed.
The lighting is poor and patchy
Many of the vehicles travelling the lower deck do not have lights on.
The road surface is patchy and potholed
There are a lot of unforgiving kerbs and concrete barriers
The signage disagrees with itself (speed limit is 30 mph and 20 mph just along)
Access ramps are just as cycle-unfriendly as the lanes.
Plenty of cover if someone wanted to lurk in the dark and accost a hapless cyclist.
Culture of bogans, chavs, yobbery and dangerous driving later at night.

Street View has a real problem following the level - it pops you between levels on the same road, which leads to the point that there is an upper and a lower deck, that both follow the same course.  Why would you confine yourself to the narrow dark and dingy lower deck?

The one advantage of the lower road is if its raining, you'll be covered for some of our journey.  However the cars will also be wet, making for slipperier roads and dirtier road spray.  The driver's vision will also be obscured to some degree, lowering your safety just as much if you were in the open.

This idiot has recorded a ride on the lower deck.  He's giving all cyclists a bad name with his riding style, and I see no lights at all.

Other Routes
This PDF has some useful info  http://chicagocompletestreets.org/wp-content/uploads/2016/01/2016-Chicago-Bike-Map.pdf

Here's a snip showing just the whacker drive area.  Franklin, Wells, Dearborn and State are all north/south roads with some kind of bike space.  Washington, Lake (?) and Harrison are all east/west roads with some bike considerations.  You've got some options.

Supporting Links

http://www.chicagotribune.com/news/ct-lower-wacker-drag-racing-met-20150717-story.html


Lock for extremely frequent use Are there lock products out there specifically designed for easy handling when locked unlocked dozens of times a day?

I'm using a normal, chain-based lock at the moment and I'm annoyed because

I'm doing constant slight damage to the frame when removing the lock from the bicycle
I need to carry a key at all times, fumble it from my pocket when it's time to go (often in a thankless, noisy, roadside environment), and fumble the lock back onto the bicycle

Are there any solutions out there that make frequent use as painless, and still as secure, as possible? I'm thinking about something that works like a remote-controlled car door lock. It should, however, still be possible to attach the bike to an object to prevent it from getting carried away.

  Related: best bike lock

For frequent use, I think it is hard to beat a lock that is built into the bike, e.g. the Axa Defender that is fixed to the fame of the bike and then locks the wheel; it also has a cable that you can use to lock the bike to the bake stand.  It’s great for a lock on a “everyday” bike, as you can’t forget to take it with you.


How to grease a hub? I have a question about hub,

When should I grease my hub ? every 20000 km ?
How do I know it needs new grease ?
Because I can not see if the grease is dry or not...?

Thanks

For a standard loose-bearing hub, to grease it you disassemble it, wash the components in solvent, and then reassemble with new grease.  You may want to take this opportunity to replace the individual balls in the assembly.

As to how often you may need to do this, it's a little bit of a wild guess.  I aim for (very roughly) every 10K miles, but a lot depends on conditions (and mine are commuting/touring).  If the bike is rarely exposed to rain and dust then longer is OK.  If it's regularly exposed to water/dirt then more often.

Some wheel bearings are advertised as "sealed", as they have a rubber seal that helps keep dirt out.  These can either be of the loose-bearing variety (which is serviced as above) or a cartridge (which cannot be serviced other that to replace it).  Sealed loose-ball bearings can probably go about twice as long before servicing.  Cartridge bearings you generally ride until they obviously need replacement.


Brake bleeding without bleeding block Is it ok to bleed my brake without a bleeding block and without removing the wheel?

What is the effect on the lever?
Will this result in a less firm lever?

It is not recommended to bleed without removing the wheel as:

It is easy to contaminate your pads with spilt brake fluid
It is likely to result in overfilling your brake system. (resulting in pads not fully retracting and rubbing on disk).

You can make your own bleed block from common household items.
I followed the guide here:
http://www.epicbleedsolutions.com/blog/how-to-make-a-bleed-block/


How to dry out the inside of a bicycle frame? I have a bicycle with a high carbon steel frame. For the most part, this frame is sealed off from the air, but there are some bolts, through which water can get through during rainy days or when washing the bicycle. I am concerned this could cause rust.

Is there a method by which to dry the interior of the bicycle out, to avoid rust?

The most important thing to do to keep the inside dry and prevent excess rust is a proper drain hole on  the underside of the bottom bracket. Outside of issues with heavily salted roads, drain holes are enough to prevent meaningful rust. The next step is something like Weigle framesaver, or just a blast of aerosol lube every couple years in each tube. Framesaver is great against salted roads, but otherwise is usually overkill.


Replacement or comparable model for my current Bottom Bracket I am currently using a old mountain bike which is using a Shimano BB -LP26 / 68 x110 Size: BC 1.37x24
I am not sure if this model is with english treading or Italian treading. I understand the don't make this type of BB anymore.

Can someone help me or give me some idea to what other Shimano models can I use for this old bike.I am bringing my old MTB back to life. The frames are in excellent condition.

I need all the help I can. Thanks guys

Pretty much any square-taper BB with the same spindle length will work. Doesn't even have to be Shimano.

1.37" x 24tpi is English, like almost all mountain bikes. (If it is Italian, it'll be immediately obvious when you try to install it - the shell diameter is a couple mm greater.)


Unable to pedal when in high gears I'm a complete novice with bicycle maintenance and have a slight problem.  I just picked up a 2nd hand bike as taking part in a charity event this weekend and an unfortunate accident meant my mine was totalled and I couldn't afford to be picky.

The bike is an 04 Giant OCR Zero with Campagnolo groupset.  An okish bike and would've been fine as a temporary machine.  I wasn't able to test ride as my knee is still battered and when I got home I flipped the bike and ran through the gears.

we have 3 on front and 9spd at the rear.  When using the biggest ring at the back and biggest at the front, the tension on the chain is so great that it cannot move.  If the rear is in mid position or lower then it transitions ok but not otherwise.

Any help or advice on how to fix is appreciated.  I thought changing the chain might solve but the chain on there is a 9 spd and as far I know, it should be fine.  replacing it with the same length would just result in the same problem.

Edited to add pics and info.
Apologies for incorrect use of tension. I've taken a few pics(hopefully they've attached ok) showing the different states of the rear mech as I transition through the gears. There is a lot of crud but no slack on the chain at all

Thanks again!

The chain is stuck because of its short length and cross-chaining - the chain links are severely bent. Also with the chain not clean it will not turn nicely in such a scenario:

Also your chain is short, making your derailleur stretch forward (marked blue) which makes the cross-chaining even more severe (marked red). On such a stretched derailleur there are bad side forces (maybe the little wheels in the derailleur get stuck while being bent).

For old drive trains cross-chaining was not accounted for as it is bad practice. Such rear derailleurs usually doesn't have a range like new ones. New bikes are designed to handle cross-chaining and such a chain would be definitely too small for them, but for old bikes it's more complicated. Looking at first picture where you have small-ring + small-gear (the shortest chain length) your derailleur could accommodate for a bit longer chain making the setup safer if you accidentally shift into big-ring + big-gear.

You can have the same gear ratio using other gears instead of cross-chaining:

You can see that 48T front 32T back (big-big) gives the same ratio as 36T front 24T back (middle-middle) which makes the chain straight.

The not-cross-chaining rule:

for small chain-ring use only the bigger half of your cassette
for middle ring you can use all your cassette
for big ring use only the smaller half of your cassette

In practice it's even less as this table of gear ratios explains (this is for 44-32-22 crank and 11-32 teeth cassette):

You only need to cover with the big and small ring what cannot be covered with the middle ring. See how this XTR9000 Di2 Syncro-Shift is shifting. When it shifts the front it also shifts the back at the same time, and it prevents cross-chaining. This video also shows gearing efficiency.


How do I tighten up my headset? I've got an old bike with a quill stem, and the headset arrangement has a nut, and a textured lock ring. I presume I should tighten with a combination of a spanner and mole grip. Is a mole grip the right tool for the job?

I believe this style is meant to be tightened by hand.

To tighten, start by tightening the knurled/textured upper race a little harder than you intend it to be once you're done.

Next, add the washer and screw on the locknut as hard as you can without tightening the race any more than it already is. Too tight and you may damage the races and need a new headset.

Then whilst holding the locknut still with a spanner, unscrew the race by hand as hard as you can. The idea is to be it clamped against the locknut so neither can move.

You may need to experiment with how tight you start to get the right tightness at the end.

PS. Mole grips are almost always the wrong tool.


Bicycle slipping gears on middle sprocket gears 4-7 I see lots of questions on gears slipping but not sure it's the same as what I have.  Out of 21 gears I only have problems with 4 (middle sprocket (2) on left shifter gears (4-7) on right shifter). Since it's only 4 gears I didn't feel comfortable adjusting anything since it may impact what's working now. I'm not sure what to look for but the sprocket, gear and chain wear look okay. I just bought the bike a couple weeks ago (used) and it shifted good through all gears. Bike is 2011 GT Aggressor that looks like new so it's not one of the 'mart' bikes.  Any ideas?  Thanks in advance.

This sounds of cable stretch. For new bikes I like to completely retune the rear dérailleur after a couple of weeks of riding. For used bikes having this problem I also check that the hanger is straight. Checking the hanger requires a special tool, so a trip to your LBS is probably in order if tightening up the cable doesn't do it.

Some folks will tell you to just turn the barrel adjuster for a stretched cable...my $0.02 is that the barrel adjuster is to allow you to make adjustments if needed during a ride. If you "use up" all the turns the adjuster has before your ride...well.

Adjusting for tension is pretty easy. Shift all the way to the smallest/hardest gear. Look at how the cable is routed...you aren't going to take it off, but just in case it gets loose, you want to route it back the proper way. Now loosen the hex bolt holding the cable. It should be a 5mm hex, just a bit should do it. Pull the cable tight. You can use a pair of needle nose pliers to help, I prefer to use fingers. If I'm not getting it tight enough, you can push the derailleur in a gear (or two depending). Tighten bolt onto cable. If you pushed on the derailleur for extra tension, pedal a bit to make sure it drops back to smallest cog (if not, loosen cable and try again...this time pushing derailleur less or not at all). Make sure it shifts all the way through...you shouldn't have to change stops, but check them. Shift to center of cog and adjust (you can use barrel adjuster here) chain so it's centered on cog (moving chain is easiest to see). Shift up and down several times, everything should be smooth.

If the cable tension doesn't work...it may be a bent hanger...stop by your LBS. The other possibilities are worn chain and/or worn cassette. Check the chain with a gauge. Cassette your LBS will be able to tell you...I'm guessing it's not this because it shifted good when you first got it.

Happy Riding.


How should I prepare a carbon frame when I want to swap in a new bottom bracket? My four-year-old, carbon-framed road bike has developed a case of creaky cranks.

I only hear creaking when pedalling hard, when I pedal more softly it just sounds like it has always done.

Given the bike's age it just seems like a good idea to replace the bottom bracket. But I was wondering, once I get the old bb out, how best to prep the frame before fitting the new bb?

I've only changed BBs on steel frames before, where I applied some pretty thick grease quite liberally around the shell. But is approach applicable to carbon?

Some supplementary info: I'm riding a 2010 Giant TCR Advanced 2, with a 6700 Ultegra groupset, including hollowtech 2 cranks. I believe from the bike's spec that the bb involved is a press-fit bb, as shown on the Wiggle site. Having said that I've not taken anything off yet so this is all theoretical so far - I'm going to visit my LBS later today to get the relevant preload cap removal tool, so I can have a bit of a look around.

If it is a press fit then it is probably a BB86.  You'll need a removal tool (Park BBT-90.3, I think) and a press.  Get a SRAM GXP press fit bottom bracket or the equivalent Shimano part, they run about $40 USD. Knock the old one out with the removal tool and a hammer, clean the inside of the shell and press in the new one.  No grease.  The shells of these bottom brackets are made of a very hard plastic that will eventually loosen and start to creak.


When to change derailleur pulleys? A friend said me that if you have one part in a very bad condition like a cassette and then you put a new stuff like a new chain it will destroy the new stuff very quickly. A LBS said that I should change my derailleur's pulley wheels after I said that the derailleur has undergone at least 10Mm. Then again, another LBS said that I should change only the cassette and the old derailleur pulleys do not matter. Hence, I am very confused. Are there any objective ways to state when one should change derailleur pulleys?

The diameters of the pulleys in the picture are about 3.6cm above and about 4.0cm below. They seem like the products here. Cannot find the specs of the original ones to compare, yet.

Worn derailleur pulleys (also known as "jockey wheels") will not cause excessive wear on a chain because they aren't made of metal.

Eventually, though, the bushings inside will become worn and the outer teeth will wear down.  Park illustrates the latter progression in their article on rear derailleur overhaul.

As with many things in bicycle maintenance the only objective metric for replacing something is that it no longer works satisfactorily.  Their failure mode might best be described as gradual rather than catastrophic.  If the pulley bushing doesn't have much slop in it and the teeth are still capable of guiding the chain effectively it's almost certainly fine. If the rest of the drivetrain is in new condition and there are still issues with shifting it's probably worth giving them a look.

As far as the practical matter of replacing them goes, in my experience for the most part you need to find the manufacturer specification to track down compatible replacements.


Increase the height of my handlebars to reduce back pain I have an early 80s Trek 970 Single track that is an awesome bike, but as an older rider who doesn't ride trails as much, would like to ride in a more upright position.  The handlebars are for the most part straight across and am just looking for a way to increase the height of the handlebars to make the ride a little more comfortable.

You need either a shorter (stem)[https://bicycles.stackexchange.com/a/270/19705]  (brings the bars closer) or to raise the stem.

The age given strongly suggests its a quill stem, and will look like this on the inside.

Back off the clamp bolt  (may be a hex socket or a bolt head) a couple of turns, and then gently tap down on the top of the bolt to loosen the clamp down inside your head tube.   Don't undo it fully unless its seized with rust and you have to get grumpy.

Once loose, pull the stem up a bit and retighten.  Go for a test ride and see how it feels.

WARNING Be mindful of the minimum insertion marks and obey them.

Once you're happy, tighten up the clamp bolt properly after checking the stem and front wheel are in line.  Use a ruler - don't just eyeball it.   Also avoid overtightening the clamp bolt.

If adding height doesn't help, you'll need a shorter stem, or possibly bars with a little more swept-back and some more uplift.  This starts costing money though.


Using 16 hole front rim to build a rear wheel I have the opportunity to buy 2 front Shimano Dura Ace C40 latest generation wheels at a very cheap price. The hole count for the wheelset is 16/21. Could I build / have built a rear wheel from one of the front rims, for example using a 32 hole rear hub or is 16 hole too fragile for a carbon rear rim?

I don't have the hub yet, but from research I assume this is the most equilibrated option, correct? With these, do you think I would need new spokes or can I reuse the ones which come with the 16 hole hub? One of the patterns I saw could work, it doesn't require any crossing. Maybe the rear hub could interfere a bit though? The video corresponding to the screenshots supposedly is a professional wheel-builder as he was a making a project for a 16 hole rear wheel, tough steel / aluminium one.

There is also a review from CyclingTips comparing the new generation wheelsets with the old ones. There is a part where they say only the rear tubular version rim is asymmetric.

Sixteen spoke rear wheels do exist, but there aren't very many of them, and to function they need to have extremely stiff and strong rims. In this case, being a Dura-Ace product, it's reasonable to assume that the everything has already been pushed to around the limit in the design. In particular, making one of these a rear would require the compromise of either pushing the drive side spoke holes way beyond what they were expected to endure in terms of resisting cracking, or making the whole thing have way less tension than intended, resulting in it being weak. Just winging it and assuming you'll be fine is not a good idea here.

These limitations don't have to do with the rim being carbon per se.

Worth mentioning but pretty far down the list of issues with this plan is that the sort of rims these are (deep carbon rims in an ultra-premium prefab set) can have directional drilling that will contort the nipples around if a pattern other than intended is used.


Minimizing the pain in Biceps and Shoulders due to Mountain Cycling or Offroad cycling I am a regular road cyclist, but I seldom go off the roads for cycling and Mountain Cycling. The terrain being damn rough and uneven, the jerks and the vibrations cause a lot of pain and numbness in Arms and Shoulders after a specific amount of endurance.

Have anybody tried a kind of a posture or may be skin-tight attire so that it is reduced? Or, how can I practice to endure such vibrations? This is rather a bit (or a lot) different than a regular exercise routine for strength building, isn't it?

EDIT: It doesn't have front and rear suspensions.

Four factors I can think of

bike
tires
riding style
conditioning

If the bicycle has full suspension then less vibration.  Carbon frame will absorb vibration.    The fit of the bike is a huge factor.

Larger tires at lower pressure will absorb vibration.  Can run tubeless tires at lower pressure.   If you are running smaller tires then go to a bigger tire like 2.2 - 2.4 if your frame will allow.

Riding style has a lot to do with arm and shoulder fatigue. Try and relax. Move your body forward and back. Don't muscle the bars. Get in the middle and let the bike rock under you. Even if you can just learn to relax between the ruff sections you will gain a lot as the muscles get a chance to recover and get more blood flow.  Watch a good rider on ruff downhill - they are relaxed and a beginner will be tensed up fighting it the whole way.

The more you ride trails the more you will condition those muscles.  In the gym push up, pull up, fly, ...  Whatever is sore find the exercise that engages that muscle.


Tapered fork steerer tube measurement I have a used a carbon fork i'm looking to sell (I bought it used and never ended up using it).

When I bought it, it was meant to be tapered 1 1/8 to 1 1/4 (1.125 to 1.25).

I'm measuring it (with measuring callipers) before I post the ad:
The top of the tube is exactly 1.125" (as expected), but I found the bottom was 1.326", which is a bit different from the 1.25 I expected (but it's way below 1.5 to think that I had the wrong specs of the fork).

Could someone shed some light on this, please?

Is this normal for a tapered 1 1/8 - 1 1/4 fork? Or is it a defect or something?

I wanna make sure I'm selling a good fork that matches the description.

Thanks in advance.
Khaled

PS. There's no crown race on the steerer. This is just the steerer on its own.

PS2. If it's any help/relevance, the fork is for a Cannondale CAAD10 (don't know about the year).

This is what it was purported to be. The crown race seat area where you're measuring should be more like 33.03-33.09mm (or around 1.302") but I suspect you're not pulling the caliper quite tight enough when you take the measurement.

Originally, though they've never been a common size, there was such a thing as a 1-1/4" non-tapered steerer tube. If you had one of those to measure, you would find the diameter of the steerer was indeed 31.8mm/1.25". But the crown race area down at the bottom is always a little larger. What's confusing here is that because of how the taper has been done, there really isn't a straight 31.8mm/1.25" section to measure.

All that said, this fork is mostly only useful as a replacement for certain CAAD and Synapse models. It won't fit many other bikes.