Disc brakes on high-end road bike?

saccades

D13exile wrote: »

Saying that, I'm planning on getting a new road bike next year and I'm stuck with the dilemma of rims/hydraulic brakes. The issues I have are ease of swapping out a wheel to fix a puncture, maintenance of disc braking systems and the weight penalty

I'll add another. Disc rims don't need a braking track and as such last way longer than rim brakes despite being lighter..

Less rotating weight is always good.

gaffmaster

Anyone got recent experience of cable actuated disc brakes?

I'm looking at this Cannondale CAADX and wondering why they wouldn't spec a hydraulic system. I've heard bike packers prefer the trailside/roadside maintenance advantages of cable disc, but how are they in terms of braking?

My only experience of cable actuated disc brakes were on a rental mountain bike that lived out in the rain. There was a lot of squealing and rust. Not a nice component to use - but again, could have been the living conditions/lack of servicing.

Lumen

Cable discs are cheaper. That's all.

saccades

gaffmaster wrote: »

Anyone got recent experience of cable actuated disc brakes?

I'm looking at this Cannondale CAADX and wondering why they wouldn't spec a hydraulic system. I've heard bike packers prefer the trailside/roadside maintenance advantages of cable disc, but how are they in terms of braking?

My only experience of cable actuated disc brakes were on a rental mountain bike that lived out in the rain. There was a lot of squealing and rust. Not a nice component to use - but again, could have been the living conditions/lack of servicing.

The only ones that are any good are BB7's (not the fives).

Lumen

I had BB7s. They were crap.

Type 17

Cable disc brakes, properly set up, are very good, and a step up from rim brakes, as the power and modulation is better.
Saying that, they need regular adjustment as the pads wear, which can be a bit tedious - hydraulic brakes self-adjust because more fluid drops into the system as the pads wear.

If I was considering whether to go rim or disc, the disc would always be hydraulic - they're easy enough to set up and bleed, once you buy a suitable kit.

As mentioned, the only time cable discs would win over hydraulic is when doing very remote touring, where you'll have to carry your own tools and spares, and do it all yourself.

saccades

Lumen wrote: »

I had BB7s. They were crap.

Tbf, they should've been right up your ****ing alley as each pad is 100% position adjustable so you can set them up in 30 seconds to have no lever throw at all.

If your talking about lack of braking you didn't bed the pads in very well or had too small a rotor.

Lumen

saccades wrote: »

Tbf, they should've been right up your ****ing alley as each pad is 100% position adjustable so you can set them up in 30 seconds to have no lever throw at all.

If your talking about lack of braking you didn't bed the pads in very well or had too small a rotor.

There are two issues:

1. Only one pad moves and they're not self-adjusting. But then I guess neither are rim brake pads.
2. Despite quite a bit of investment in incompressible outers and clean cuts, I could never get the rear brake to feel good.

The bedding in process is tolerable, you only do it once for a set of rotors.

Type 17 wrote: »

Cable disc brakes, properly set up, are very good, and a step up from rim brakes, as the power and modulation is better.

I disagree. Rim brakes with good pads on alloy rims can lock up both wheels, so the power is plenty, and the modulation is better IMO than cable discs. Particularly the rear. The only reason to prefer them is to run massive tyres (I have them on a bike with 40mm slicks).

flatface

Last question on disc brakes - If someone, not me of course, was very bad a cleaning their bike, are discs good or bad? My friend says his rim brakes are always sub-optimal due to dirt on the rims, do discs need to be cleaned more/less?

Lumen

I clean my disc braked bike about twice a year and never go near the brakes. Maybe once a year they get serviced in a shop.

Type 17

Lumen wrote: »

I disagree. Rim brakes with good pads on alloy rims can lock up both wheels, so the power is plenty, and the modulation is better IMO than cable discs. Particularly the rear. The only reason to prefer them is to run massive tyres (I have them on a bike with 40mm slicks).

In fairness, it probably does also depend on the quality of the kit - a decent set of rim brakes with good pads is almost certainly better than a cheap cable-disc setup, where they've specced the cheapest stuff available just so that they can boast of disc brakes at a particular price point...

flatface wrote: »

Last question on disc brakes - If someone, not me of course, was very bad a cleaning their bike, are discs good or bad? My friend says his rim brakes are always sub-optimal due to dirt on the rims, do discs need to be cleaned more/less?

Discs are probably worse for a "maintenance-free" bike - although the brake surfaces will generally keep themselves clean in both disc and rim setups, the result of oil contamination is much more severe with discs (horrendous squealing as well as poorer stopping power). Additionally, permanently dirty disc callipers can cause the pistons to stick, and eventually, the seals and bores fail from grit contamination.

Rim callipers are much more forgiving of filth, but even they will eventually seize from wheel-spray with no mudguards, but then they can often be disassembled and cleaned out, if their replacement cost is high enough to justify the rebuild costs.

PS: Maybe actually clean your ("friend's") bike every so often - your LBS can do it for a reasonable fee if you don't have the space or facilities.

saccades

Lumen wrote: »

There are two issues:

1. Only one pad moves and they're not self-adjusting. But then I guess neither are rim brake pads.
2. Despite quite a bit of investment in incompressible outers and clean cuts, I could never get the rear brake to feel good.

The bedding in process is tolerable, you only do it once for a set of rotors.



I disagree. Rim brakes with good pads on alloy rims can lock up both wheels, so the power is plenty, and the modulation is better IMO than cable discs. Particularly the rear. The only reason to prefer them is to run massive tyres (I have them on a bike with 40mm slicks).

Wrong brakes.

BB7s have TWO fully adjustable moving pads, you must have used the BB5's which only have the out board pad adjustable.

Not sure about your rear problems, I use full length outers and it's been grand for over 7 years at this point. Some people have used oilers to lube as I guess it might be a friction thing

Type 17

Interesting article about cleaning disc brakes and preventing contamination in the first place:

https://off.road.cc/content/feature/whats-the-best-way-to-clean-disc-brakes-on-a-bicycle-2937

cdaly_

saccades wrote: »

The only ones that are any good are BB7's (not the fives).

Lumen wrote: »

I had BB7s. They were crap.

I have a BB7 (rear). It's great. Occasional pad adjustment required (not need on hydraulics) and that's it.

saccades wrote: »

BB7s have TWO fully adjustable moving pads,

I think Lumen's talking about only one pad moving when you brake. The inboard pad moves only for setup/adjustment, after that the outboard pad presses the disc onto the inboard.

Lumen

cdaly_ wrote: »

I think Lumen's talking about only one pad moving when you brake. The inboard pad moves only for setup/adjustment, after that the outboard pad presses the disc onto the inboard.

Thanks, that was it. And the pads aren't self-adjusting like hydraulics, so there's a bit of fettling to keep them running well. But the maintenance is definitely easier than hydraulics, and almost as easy as rim brakes.

Still, I would only consider cable discs for a loaded tourer that was going somewhere without good bike shops, or if I was on a very tight budget. Hydros are so good now....