Rim Brakes on Carbon Wheels
05-27-19, 10:52 AM
#51
RacingBear
I rode on carbon rims once. When I tried to brake a portal in to the other dimension has opened and Cthulhu almost came through it.
small correction... "For their slaves to build the pyramids." Who probably would have been happier with wheels...
05-31-19, 06:05 PM
#53
Full Member
1. American made deep aero section carbon wheels are so expensive that you might want to protect your investment with disk brakes. Bikes really have to be engineered especially for disk brakes so unless you're buying one new I wouldn't pay the huge sums for an American deep aero section wheel set. And remember that braking wears out pads and braking surfaces. Road disks are so small that they wear pretty fast and the pads themselves continually need replacement. It is NOT difficult to lose a pad and hence your braking if you don't keep that pads in good shape.
2. Chinese carbon clinchers are CHEAP and they cost less than a good aluminum wheel. The brake track on these using the basalt or cork brake pads that come with them can be expected to last about as long as light aluminum wheels with normal brake pads. Perhaps longer. There is the problem that aluminum conducts heat faster than run-of-the-mill carbon fiber does. You CAN overheat and not be able to stop. So you always have to plan ahead. The aero wheels are so much faster than box section aluminum wheels that being careful 1% of the time is well worth it.
3. So far my experience with the cheap Chinese tubeless wheels is not the best possible. These wheels are 55 mm deep section but they appear to be using the spoke set for the 50 mm deep clinchers. This means that the spoke tension is FAR below what it should be and the wheels tend to wander about in side gusts. The clinchers with good tight spokes do not do this. The aero sections themselves are so strong that they can get away with less than optimum spoke tension.
4. You cannot expect to be able to do more than do slight adjustments on these wheels because the spoke nipple beds are not the same from spoke to spoke as they are on aluminum wheels. I think that these wheels are built on a machine that tightens the spokes via torque measurements.
2. Chinese carbon clinchers are CHEAP and they cost less than a good aluminum wheel. The brake track on these using the basalt or cork brake pads that come with them can be expected to last about as long as light aluminum wheels with normal brake pads. Perhaps longer. There is the problem that aluminum conducts heat faster than run-of-the-mill carbon fiber does. You CAN overheat and not be able to stop. So you always have to plan ahead. The aero wheels are so much faster than box section aluminum wheels that being careful 1% of the time is well worth it.
3. So far my experience with the cheap Chinese tubeless wheels is not the best possible. These wheels are 55 mm deep section but they appear to be using the spoke set for the 50 mm deep clinchers. This means that the spoke tension is FAR below what it should be and the wheels tend to wander about in side gusts. The clinchers with good tight spokes do not do this. The aero sections themselves are so strong that they can get away with less than optimum spoke tension.
4. You cannot expect to be able to do more than do slight adjustments on these wheels because the spoke nipple beds are not the same from spoke to spoke as they are on aluminum wheels. I think that these wheels are built on a machine that tightens the spokes via torque measurements.
05-31-19, 07:16 PM
#54
Senior Member
Thinking of buying a road bike with rim brakes and carbon wheels? Do you already have a road bike with rim brakes and you want to switch from alloy to carbon wheels? Stop and consider the following:
Bikes are lousy at stopping quickly at speed or steep descent no matter what the situation is. But you have rim brakes on your current bike and you want to go from alloy to carbon wheels you may regret the choice when you try to make descents that require slow speeds down steep descents. The difference as I found about between carbon and alloy after switching is greater than I had participated. (The heavier you are the greater difference with carbon than alloy.)
The bottom line the carbon wheels are much less effective than alloy for breaking the situations I describe
Many carbon wheels come with a braking track on the wheels for a better grip by the brake pads. Those wear out in a month or so.
Anyway, a factor to consider if you are considering going from alloy to carbon for whatever reason.
Bikes are lousy at stopping quickly at speed or steep descent no matter what the situation is. But you have rim brakes on your current bike and you want to go from alloy to carbon wheels you may regret the choice when you try to make descents that require slow speeds down steep descents. The difference as I found about between carbon and alloy after switching is greater than I had participated. (The heavier you are the greater difference with carbon than alloy.)
The bottom line the carbon wheels are much less effective than alloy for breaking the situations I describe
Many carbon wheels come with a braking track on the wheels for a better grip by the brake pads. Those wear out in a month or so.
Anyway, a factor to consider if you are considering going from alloy to carbon for whatever reason.
I have not read the whole thread after your post, but i can say that it has been a "known fact" that carbon rims will do worse with rim brakes for about 10-15 years now. theats why they invented dics brakes like 20-25 years ago. I remember you could get sachs disc brakes in 1994-1995.
the reason the carbon pads wear pout fast is because they try not wear out the carbon rims. you need to sacrifice something right? whats cheapest?
Personally i have never understood why people complain about carbon rims wearing out. THIS IS WHAT YOU F-ING CHOSE!! You chose this on your bike.
I didnt choose any carbon rims on any of my bikes. not 10 years ago and not now. I wonder why that is?
I actually "unchosed" rim brakes for all but 1 bike i built in the last 10 years. Because that bike could not be had with discs. so rim brakes it was. i sure didn't put carbon wheels on there though.
I guess you live and you learn. and now you learned something.
Carbon fiber is 50% epoxy plastic. you heard it here first.
05-31-19, 07:22 PM
#55
On Your Left
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I have Zipp 303s and white there are not a lot of long descents on Long Island they stop just fine for me.
05-31-19, 07:29 PM
#56
Senior Member
and they probably will do for most people. until the end of time.
06-09-19, 06:14 PM
#57
Full Member
I used Bontrager carbon wheels for years and more recently Zipp 404's and CLX 50's and do a lot of mountain rides. The only time I do not prefer carbon is downhill and stopping in the rain.
06-11-19, 04:48 PM
#59
Advocatus Diaboli
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