Riders on disc brakes. How often do you lock up your rear wheel?

Discuss light weight issues concerning road bikes & parts.
User avatar
mpulsiv
Posts: 1274
Joined: Mon Mar 24, 2014 9:17 pm

by mpulsiv

Miller wrote:Got my new Campag Potenza disc brakes in operation and am loving them, they're the best brakes I've ever used. I should qualify that by adding I have not been in the habit of crashing due to brake deficiency, I have a bike with perfectly effective rim brakes, but the disc brakes give you a feeling of having masses of controllable stopping power. The modulation is excellent. You can lock the back wheel if you choose to but it's not something that should happen unless you panic.
Tell me more about Potenza disc. I bought Potenza rim brake groupset blindly, without a test ride. Functionality and performance has been exceptional. How do you like Potenza disc next to Shimano? Modulation? Clearance between pads? Noise? Quality of a rotor? Raw stopping power?
Racing is a three-dimensional high-speed chess game, involving hundreds of pieces on the board.

:arrow: CBA = Chronic Bike Addiction
:arrow: OCD = Obsessive Cycling Disorder

by Weenie


User avatar
Miller
Posts: 1405
Joined: Thu Sep 21, 2006 8:54 pm
Location: Reading, UK

by Miller

Yes, current Potenza is very, very nice. Lovely front shift. The EPS style downshift lever is a treat too.

The disc brake group is on my CX bike, a Genesis Vapour. I had never fitted hydro discs before but with checking the Campag youtube videos first it was straightforward. Specialist tools: the brake fluid + syringe kit, the metal block to space the pistons at correct distance apart.

That was in May, since then I have put 1300km on the Genesis including a holiday in France in the high mountains. Highlights are that modulation and outright stopping power is outstanding. There's masses of power on tap without much hand effort. (I can lock the rear wheel with ease, should I want to do that.) The braking ease gives you confidence on the bike, not just on some glamour Alpine ride, but when hacking through Reading town centre traffic which is more of my regular experience, or picking my way down a flinty Chiltern path. The AFS rotors are very nice with a smooth rounded edge because, you know, spinning knives.

Lowlight is that the discs can be noisy. First of all there is a short period of rubbing noise after a moment of heavy braking. From what I read this seems to be endemic to disc brakes from any vendor while they're dumping heat. More annoying can be a screech when the pads are touching the rotor very faintly. It has been a very dry summer here and I have wondered if that has been allowing pads to get a bit glazed. Some wet rides might cut through that and doubtless there will be some of those before long.

I don't have much experience with the Shimano alternative but in France I did have a ride on a bike kitted out with an Ultegra disc group. Frankly the brakes behaved very similarly to the Campag ones including being noisy after braking. I felt they didn't quite have the outright stopping power of the Campag brake.

Image

TobinHatesYou
Posts: 2043
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

That ting-ting-ting noise after heavy/hot braking only happened to me when I didn’t align my calipers well enough.

glander
Posts: 53
Joined: Sat Feb 24, 2018 3:07 pm

by glander

Never, but then again I probably use the front brake 60 / 40 over the rear. I use Sram Etap HRD. Hope this helps

Theologian
Posts: 41
Joined: Sat Jun 23, 2018 3:34 am

by Theologian

After getting loud deep-rim aero carbon wheels, I can't hear anything but the tires and wind.

jfranci3
Posts: 371
Joined: Tue Jul 26, 2016 5:21 pm

by jfranci3

Tried a 140mm H11 rotor with my SRAM setup. For some reason, the H11 rotor makes a gravelly noise under hard braking until the pad heats up. The caliper is aligned and seated firmly. I put a black line on the rotor, which shows the pad is sweeping correctly (not too high or low). The campy pads must be longer than the Sram ones.
In any case, I think I found my issue. The barb on my brake hose was an aftermarket one from Amazon. Looks like the orifice is about 1.5x the diameter of the SRAM ones I bought. If the shiftier side, caliper, and line diameter are also larger, that'd allow me to easily shock the rear tire on brake application and lock the rear. I'm tossing the 160mm back on too, since the Campy rotor isn't working for me.

TobinHatesYou
Posts: 2043
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

The vent design on H11 rotors matched with SRAM calipers = a whistling or gurgling Chewbacca noise. I've mentioned this already. :p

jfranci3
Posts: 371
Joined: Tue Jul 26, 2016 5:21 pm

by jfranci3

Definitely groging Chewbacca through a PCV tube

WorkonSunday
Posts: 42
Joined: Tue Jan 16, 2018 4:39 pm

by WorkonSunday

MTB <-- alot (SRAM guide RS, Shimano XTR, Shimano Saint)
Road <- only once (shimano CX77 [cable disc brake])

PS: i dont like the hydraulic hood design from the big threes so i stuck with cable disc brake. it's an improvement over rim brake but not overly so.

Stickman
Posts: 69
Joined: Sun Oct 08, 2017 1:58 am

by Stickman

Once, on a downhill panic stop, for a split second before I backed off and got things under control. Otherwise, never.

uraz
Posts: 98
Joined: Thu Dec 12, 2013 9:48 pm

by uraz

I can not resist the impression that most people confuse good modulation with a lack of power.

jfranci3
Posts: 371
Joined: Tue Jul 26, 2016 5:21 pm

by jfranci3

uraz wrote:
Wed Oct 10, 2018 9:05 pm
I can not resist the impression that most people confuse good modulation with a lack of power. Every time I read that some brake has "good modulation" I just know that it will be weak as hell (aka noob-proof). Current genereation of road disc brakes have exactly this kind of "good modulation" which is why I don't like them.

Preventing wheel lockup is not a brake's job. If you don't want to skid just don't squeze lever so hard or let it go slightly when you feel that tire is on the edge of traction.

"How often do you lock up your rear wheel?" - whenever I want to, regardless of a brake type I use.
Is this a troll post?

uraz
Posts: 98
Joined: Thu Dec 12, 2013 9:48 pm

by uraz

No, why? Fact that I don't have a problem with unwanted wheels locking doesn't make me a troll.

TobinHatesYou
Posts: 2043
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

Not a troll, just wrong. We all know rear wheels can lock up easily no matter what brake system is used. That's why most of us are saying it's a technique/rider issue rather than a brake issue. To imply correlation between good modulation and brake strength though, that's pretty silly of you.

bilwit
Posts: 983
Joined: Sun Apr 03, 2016 5:49 am
Location: Seattle, WA

by bilwit

WorkonSunday wrote:
Mon Oct 08, 2018 7:41 am
MTB <-- alot (SRAM guide RS, Shimano XTR, Shimano Saint)
Road <- only once (shimano CX77 [cable disc brake])

PS: i dont like the hydraulic hood design from the big threes so i stuck with cable disc brake. it's an improvement over rim brake but not overly so.
The latest di2 hydraulic hoods are more or less the same as normal ones, I expect the next iteration of eTap and EPS will follow suit. Mechanical shifting.. I don't think it's possible for them to get any smaller :x

by Weenie


Post Reply
  • Similar Topics
    Replies
    Views
    Last post