3 ms·

Rim brakes on roadbikes are awesome, but they are awesome because the calipers don't have to go far around the tire. If you try to build them for wider tires yo

by usrusr 5y ago

Rim brakes on roadbikes are awesome, but they are awesome because the calipers don't have to go far around the tire. If you try to build them for wider tires you suffer far more flex and flex means that you can't pull a high lever transmission ratio before running out of lever movement. Remember "brake boosters" on cantilever brakes? Same problem, the requirement to transfer the counterforce far around the tire. I'm a rim brake die-hard, but for anything wider than 28 go disc.

vecinu 5y ago
The only caveat is carbon wheels. I hate rim brakes on carbon wheels,they legitimately suck and disc is way better for that application. I actually just sold my carbon wheels and downgraded back to aluminium until I buy a disc bike for the long term.
- matsemann 5y ago
  Rim breaking on deep dish tempo wheels sounds horrifying.
  - usrusr 5y ago
    They are certainly not the kind of wheels you'd want to use on steep roads with unpredictable weather (e.g. because the trip was planned months in advance and the bike), anybody into that kind of toy usually keeps a set of low section wheels for those occasions (or bike/bikes, if the looks just don't match). Disc brake doesn't change that by the way, because crosswinds can be brutal in the mountains.
    - vecinu 5y ago
      Discs solve my issue because 40mm deep is enough to not suffer from terrible crosswinds, if the wheels are made well. The worst problem is after a few minutes of constant breaking, which you have to do if you're descending a mountain carefully and care for your life, the rim brakes on carbon start to squeal and you lose a lot of braking power. You also used to risk delamination but that isn't that big of an issue on the newer wheels.
sliken 5y ago
I'd had just about every cable actuated brakes. Old school cantilevers, various flavors, u-brakes, v-brakes, cable-discs etc. etc. etc. Didn't realize what I was missing till I tried a nice set of hydraulic discs, I'll never go back.
- usrusr 5y ago
  That list is looking suspiciously void of brakes that would have trouble fitting a 28 mm tire. Yes, disc brakes can be very good, but the gap is much smaller than must people would expect.
  - sliken 5y ago
    Heh, I've had my fair share that would hit the limit in the 25-28mm. In particular the shimano SLR/dual action/dual lever or whatever they are called. I don't agree with the "gap is much smaller than people would expect". Have you tried a decent hydraulic brake? I raced on and off road, was a bike messenger, designed and built (from tubes) a mtb frame, and bike commuted nearly every workday of my life. Disc brakes have significant advantages over any rim brake. Don't knock them till you try them, I was dubious myself.
    - usrusr 5y ago
      Heh, I don't doubt that they are powerful and I sure won't bend over backwards to still get rim brakes next time I want/need a bike, but the "want" isn't exactly strengthened by the switch. And yes, even aluminium wheels aren't really a joy decelerating in the rain (and yes, I've been to that group ride where one guy could show off his nice new aero carbon toy while my nice new aero carbon toy had to stay at home because for a dozen hours of mostly rain as a rim rider your choice will definitely fall on the one with the aluminium wheels. I guess I just can't warm up to the idea of front wheels with twentysomething spokes. It's confusing enough already that carbon front wheels (for rim) almost universally come with 18 instead of 16, what's up with that?
      - sliken 5y ago

by usrusr 5y ago

vecinu 5y ago

The only caveat is carbon wheels. I hate rim brakes on carbon wheels,they legitimately suck and disc is way better for that application. I actually just sold my carbon wheels and downgraded back to aluminium until I buy a disc bike for the long term.

matsemann 5y ago
Rim breaking on deep dish tempo wheels sounds horrifying.
- usrusr 5y ago
  They are certainly not the kind of wheels you'd want to use on steep roads with unpredictable weather (e.g. because the trip was planned months in advance and the bike), anybody into that kind of toy usually keeps a set of low section wheels for those occasions (or bike/bikes, if the looks just don't match). Disc brake doesn't change that by the way, because crosswinds can be brutal in the mountains.
  - vecinu 5y ago
    Discs solve my issue because 40mm deep is enough to not suffer from terrible crosswinds, if the wheels are made well. The worst problem is after a few minutes of constant breaking, which you have to do if you're descending a mountain carefully and care for your life, the rim brakes on carbon start to squeal and you lose a lot of braking power. You also used to risk delamination but that isn't that big of an issue on the newer wheels.

sliken 5y ago

I'd had just about every cable actuated brakes. Old school cantilevers, various flavors, u-brakes, v-brakes, cable-discs etc. etc. etc. Didn't realize what I was missing till I tried a nice set of hydraulic discs, I'll never go back.

usrusr 5y ago
That list is looking suspiciously void of brakes that would have trouble fitting a 28 mm tire. Yes, disc brakes can be very good, but the gap is much smaller than must people would expect.
- sliken 5y ago
  Heh, I've had my fair share that would hit the limit in the 25-28mm. In particular the shimano SLR/dual action/dual lever or whatever they are called. I don't agree with the "gap is much smaller than people would expect". Have you tried a decent hydraulic brake? I raced on and off road, was a bike messenger, designed and built (from tubes) a mtb frame, and bike commuted nearly every workday of my life. Disc brakes have significant advantages over any rim brake. Don't knock them till you try them, I was dubious myself.
  - usrusr 5y ago
    Heh, I don't doubt that they are powerful and I sure won't bend over backwards to still get rim brakes next time I want/need a bike, but the "want" isn't exactly strengthened by the switch. And yes, even aluminium wheels aren't really a joy decelerating in the rain (and yes, I've been to that group ride where one guy could show off his nice new aero carbon toy while my nice new aero carbon toy had to stay at home because for a dozen hours of mostly rain as a rim rider your choice will definitely fall on the one with the aluminium wheels. I guess I just can't warm up to the idea of front wheels with twentysomething spokes. It's confusing enough already that carbon front wheels (for rim) almost universally come with 18 instead of 16, what's up with that?
    - sliken 5y ago