Disc Brakes on a road bike

MichaelW

sagalout wrote:

As someone said early in the thread, for commuting (or if you just ride a lot on busy stop start roads) in the wet discs have a real and noticeable advantage....mostly being the ability to actually stop if if a car pulls out or you hit a red light etc. For normal road riding on country roads, where use of brakes is rare and planned, it makes no difference.

..Which indicates that road disk rake systems should be introduced at commuter/training grade (105) before the Dura-Ace version.

Manc33

The "Four Yorkshiremen" sketch springs to mind.

I still remember trying cheap hydraulic disc brakes on a heavy MTB and thinking it was too powerful.

What about modulation? Is that why they are still inventing them, to get the modulation of a side pull?

monkimark

If they're too powerful, don't pull the lever as hard. Sounds like an advantage rather than a flaw.

earth

I got a disc brake bike because I wanted to try all the new stuff. I would not advise buying one that has cable pull brakes. I think the root problem is that road bike leavers do not pull as much cable as flat bar levers. Instead the road caliper provides more mechanical advantage. So when they are mated with disc calipers you have to pull the lever through about half the travel before they bite. I would wait until hydraulic road discs become available and affordable.

When I ride my other bike with aluminum rims and swiss stop pads the braking is silent, perfectly smooth with great modulation and still work well in the wet. They are just not quite as powerful.

kingstonian

earth wrote:

I got a disc brake bike because I wanted to try all the new stuff. I would not advise buying one that has cable pull brakes. I think the root problem is that road bike leavers do not pull as much cable as flat bar levers. Instead the road caliper provides more mechanical advantage. So when they are mated with disc calipers you have to pull the lever through about half the travel before they bite. I would wait until hydraulic road discs become available and affordable.

When I ride my other bike with aluminum rims and swiss stop pads the braking is silent, perfectly smooth with great modulation and still work well in the wet. They are just not quite as powerful.

I have hydraulic road discs on my new bike, they are utterly brilliant. Yes I splurged the cash on them and the bike in general, but happy with what my money bought.

negativelycra

At all emoaning cable brakes - i'm confused...

When i was younger, i used ti race 100 cc karts. Before the regs changed, we were all clocking over 100 mph, min kart weight 145 kg, cable brakes. I could modulate them fine, as could the rest of the grid.

Theoretically, there is virtually bugger all between a cable system and a hydraulic system in a road bike application. How is it that cables have such a bad rap?

mr_evil

earth wrote:

...So when they are mated with disc calipers you have to pull the lever through about half the travel before they bite...

I set up rim brakes like that because the closer the lever is to the bar, the more force your fingers can apply, so you get better braking.

earth

Negativelycra wrote:

At all emoaning cable brakes - i'm confused...

When i was younger, i used ti race 100 cc karts. Before the regs changed, we were all clocking over 100 mph, min kart weight 145 kg, cable brakes. I could modulate them fine, as could the rest of the grid.

Theoretically, there is virtually bugger all between a cable system and a hydraulic system in a road bike application. How is it that cables have such a bad rap?

There are differences. Cable pull brakes have a single moving piston. With a hydraulic both move. I'm also told they have the ability to self adjust the distance between the pad and the rotor. I've spent 2 hours messing around with the rear disc after I changed the pads attempting to find that magical sweet spot where the pads are far enough from the rotor to not drag but close enough for the brake to work when the lever is pulled. I found it but I nkow I will have to do it again in a few weeks when the pads have worn.

bendertherobot

Spyres are dual piston.

earth

Mr Evil wrote:

earth wrote:

...So when they are mated with disc calipers you have to pull the lever through about half the travel before they bite...

I set up rim brakes like that because the closer the lever is to the bar, the more force your fingers can apply, so you get better braking.

I take your point there. On my rim brakes I have a bit of travel before they contact the rim because of my short fingers. Having a bit of dead travel means I can grip the lever in the drops without braking but on the discs if I don't set the very carefully then there is almost no travel left after they bite. Then there is not enough force to lock the rear wheel when pushing the bike forward even with the lever fully applied.

earth

bendertherobot wrote:

Spyres are dual piston.

Maybe I will replace the BB5s with those.

freefall_junkie

I am old enough to remember when disc brakes first came out for mountain bikes. At first the big manufacturers hedged their bets with both disc and rim brake models in the range, exactly as they are doing now with the 2015 road models, but within just 2 or 3 years the tide had turned completely and disc brakes were universal. I fully expect the same to happen in road bikes, and the turning point will come when we see discs in the pro peloton. Rightly or wrongly the road market is very driven by what the pros ride. Having said that I bought a rim brake Bianchi Infinito CV in preference to the disc version, which was more expensive, half a kilo heavier, and less attractive to my eyes. And the latest Shimano dual pivot rim brakes are so stunningly good you really question whether discs are necessary.

Mark