Why do road bikes still use side pull brakes?

[mpvue]

Originally Posted By: dailydriver
Originally Posted By: Surestick
What you should be asking is why all bikes haven't gone to discs. The blame for that lies with the UCI (Union Cyclist International) who are responsible for determining what can and cannot be used in competition. They just recently allowed discs in cyclocross racing and bikes and they seem to be taking off there.


I wonder just how long it will be until we see them on every machine in the pro road peloton (especially for the mountain stages with 10+ mile long, multi-switchback, rim glue melting descents)??

I'm sure some teams/manufacturers have already heavily petitioned the UCI for this change.

I think you're exaggerating the potential problems. it's not like hundreds of racers every mountains stage are crashing because of blown up rims.
I seriously doubt the racers or teams want discs, they are NOT an upgrade:
1. larger diameter rotors are better for braking, an no rotor is as large diameter as the whole rim.
2. wheel changes are quicker w/ rim brakes.
3. rim brakes work just fine.
4. rim brakes are lighter.
5. cable operated rim brakes are WAY better feeling than cable operated discs. the only good feeling discs are hydraulic and it would be impossible to adapt hydraulics to a road bike lever.
6. discs put all different kinds of stresses on a frame and fork requiring a complete redesign, again, making things heavier. not going to happen in the road racing world.

off road bike design is still evolving (suspension, brake design, position, etc), whereas road bike design (geometry, drop bars, etc) has basically been fixed for some time. road bike design is basically unchanged in the last 20 years because it works.

 

[Surestick]

Originally Posted By: mpvue
Originally Posted By: dailydriver
Originally Posted By: Surestick
What you should be asking is why all bikes haven't gone to discs. The blame for that lies with the UCI (Union Cyclist International) who are responsible for determining what can and cannot be used in competition. They just recently allowed discs in cyclocross racing and bikes and they seem to be taking off there.


I wonder just how long it will be until we see them on every machine in the pro road peloton (especially for the mountain stages with 10+ mile long, multi-switchback, rim glue melting descents)??

I'm sure some teams/manufacturers have already heavily petitioned the UCI for this change.

I think you're exaggerating the potential problems. it's not like hundreds of racers every mountains stage are crashing because of blown up rims.
I seriously doubt the racers or teams want discs, they are NOT an upgrade:
1. larger diameter rotors are better for braking, an no rotor is as large diameter as the whole rim.
2. wheel changes are quicker w/ rim brakes.
3. rim brakes work just fine.
4. rim brakes are lighter.
5. cable operated rim brakes are WAY better feeling than cable operated discs. the only good feeling discs are hydraulic and it would be impossible to adapt hydraulics to a road bike lever.
6. discs put all different kinds of stresses on a frame and fork requiring a complete redesign, again, making things heavier. not going to happen in the road racing world.

off road bike design is still evolving (suspension, brake design, position, etc), whereas road bike design (geometry, drop bars, etc) has basically been fixed for some time. road bike design is basically unchanged in the last 20 years because it works.


The issue with overheating and blowing tires off rims on long descents isn't one that affects pros so much, more tandems (due to weight) and recreational riders (probably because they drag their brakes more than pros would).

Yes, larger diameter rotors offer better braking but that is made up for in disc brakes by using more mechanical advantage between the lever & the pads. The mechanical advantage you can use on rim brakes is limited by the clearance needed between rims and pads.

Rim brakes work fine until they get wet or your pads eat through your rims and they fail.

Test of a disc brake equiped road bike

Cable to hydraulic adapters for cyclocross.

 

[dailydriver]

Originally Posted By: mpvue
Originally Posted By: dailydriver
Originally Posted By: Surestick
What you should be asking is why all bikes haven't gone to discs. The blame for that lies with the UCI (Union Cyclist International) who are responsible for determining what can and cannot be used in competition. They just recently allowed discs in cyclocross racing and bikes and they seem to be taking off there.


I wonder just how long it will be until we see them on every machine in the pro road peloton (especially for the mountain stages with 10+ mile long, multi-switchback, rim glue melting descents)??

I'm sure some teams/manufacturers have already heavily petitioned the UCI for this change.

I think you're exaggerating the potential problems. it's not like hundreds of racers every mountains stage are crashing because of blown up rims.
I seriously doubt the racers or teams want discs, they are NOT an upgrade:
1. larger diameter rotors are better for braking, an no rotor is as large diameter as the whole rim.
2. wheel changes are quicker w/ rim brakes.
3. rim brakes work just fine.
4. rim brakes are lighter.
5. cable operated rim brakes are WAY better feeling than cable operated discs. the only good feeling discs are hydraulic and it would be impossible to adapt hydraulics to a road bike lever.
6. discs put all different kinds of stresses on a frame and fork requiring a complete redesign, again, making things heavier. not going to happen in the road racing world.

off road bike design is still evolving (suspension, brake design, position, etc), whereas road bike design (geometry, drop bars, etc) has basically been fixed for some time. road bike design is basically unchanged in the last 20 years because it works.



Yes, you are correct with the above, and they would not even want to make up for the weight gain with mass reductions elsewhere (due to weakening), as it would not be worth any potential gains.

BTW; what exactly IS/ARE the road and track bike minimum allowed weight(s) currently under UCI rules??

 

[JOD]

Originally Posted By: dailydriver


BTW; what exactly IS/ARE the road and track bike minimum allowed weight(s) currently under UCI rules??


15 lbs for road (6.8 kg).. I actually don't know if there's a limit on track stuff. I imagine there is, but generally those guys use heavy stuff.

I don't think it's weight that is keeping disc brakes from the road. The big reason is standardization. Neutral support would be a nightmare unless everyone switched--and not everyone would switch unless it were mandated. There would definitely be an aerodynamic penalty, with very little gain. I saw some prototype Shimano road discs over a decade ago. They looked cool, but just like tubeless road tires, they're the answer to the question no one asked...

I think they're great for tandems, cross, and bad weather commuter bikes. I don't ever see them making inroads into road racing, though. Modern dual pivots and good brake pads work really well in all conditions, even on carbon rims. The key is good brake pads.