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

Discuss light weight issues concerning road bikes & parts.
sychen
Posts: 347
Joined: Thu Apr 24, 2014 1:06 pm

by sychen

Went to Disc recently and have had an emergency stop at the same place i've done the same on the old bike.
Steep hill down to a roundabout where cars sometimes turn without indicating .. probably should slow down more as i've had a few e-stops here.

Old bike would lockup quickly and i would as i have often done, skidded to a stop but under control as a long time mtber have no issues.
Disc bike in the same situation only skid very slightly at the end but had full control the whole time with room to spare.
Frankly I was surpised how much more modulation I had in the same situation. I knew from many tests how much more modulated power I had but only in an emergency did I see how well it can be used.

spud
Posts: 675
Joined: Sat Feb 07, 2009 5:52 am

by spud

assuming noth brake systems are in good condition, disc brakes are less likely to lock due to two things:
1) less friction/hysteris in the systeme - cable friction vs lack of fluid friction
2) even a great rim set up can have a very minor variation in braking force on different parts of the rim - the sticky point can lock when the rear tire is very light on the ground due to weight transfer
I've never locked my rear disc brake unless it was on purpose

by Weenie


dricked
Posts: 73
Joined: Tue Jan 09, 2018 1:57 pm

by dricked

All the time. Skids are cool!

superdx
Posts: 516
Joined: Sun Jun 29, 2014 1:27 pm

by superdx

Never, not even when I crashed

jfranci3
Posts: 352
Joined: Tue Jul 26, 2016 5:21 pm

by jfranci3

Recently switched frames with my road tires / CX frame to same tires / road frame. The differences in the frames are slight with the same fit - 20mm seat stays and steering trail at the opposite ends of the spectrum. Also went from TRP Hy/Rd (cable to hydro) to Sram Force HRD. Same tires/wheels/160mm discs front and rear. I need to got 140mm on the rear with the proper hydro discs and the road frame. They just lock up so easily.

TobinHatesYou
Posts: 1876
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

Going to a smaller rotor will just keep on masking the real problem in your braking technique. Your rear brake is for slowing down, trail braking after entering a corner slightly too hot for example. It Is something you always apply in a controlled progressive manner. If your body can’t feel the additional braking power working and where the limit of traction is, that’s on you. How did you survive with rim brakes, which have worse modulation?

CEVelo
Posts: 99
Joined: Tue Mar 24, 2015 5:22 pm

by CEVelo

Whenever I need to drift around a corner...

Modulation is far superior on disc breaks vs. rim, so the risk of locking up the rear is reduced with a good disc system.

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

by Theologian

I've always ridden with disc brakes, first mechanical and now hydraulic, never lock out the rear wheel. But then again, I've never had to "panic brake." As other have said, well designed levers, calipers and pads have great modulation.

MikeD
Posts: 142
Joined: Thu Dec 11, 2014 9:55 pm

by MikeD

In my opinion, the more powerful the brake the more likely it is to lock it up. Modulation goes out the window in a panic situation when you're just grabbing brake without thinking. On my mountain bike, I have to squeeze the lever super hard to lock the brake so it almost never locks up. That doesn't mean I'm not going to work on improving the braking power of this brake though.

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

by Theologian

So what's next in bike tech? Anti-lock hydraulic disc brakes?

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

by Theologian

Growing up here in the Northeast, we all had to learn how to "pump" your car brakes in the winter before ABS became standard on cars. In fact, we learned to turn "into" the direction the car is sliding (against intuition) to gain traction should the wheels locked up on snow or ice. I don't think I've ever done that on a bike, the window for reaction is really small. I wonder if ABS would work on bike.

Jugi
Posts: 166
Joined: Sun Jun 24, 2018 8:10 am

by Jugi

TobinHatesYou wrote:
Mon Sep 10, 2018 5:27 am
Going to a smaller rotor will just keep on masking the real problem in your braking technique.
I wouldn’t call that a flaw in technique. At least for me, the easiest braking system to use is the one which will provide optimal stopping power when a similar amount of pressure is applied to both levers. Intuitive braking in a straight line comes first, finesse in trail braking etc. is achieved when the system works logically.

MoPho
Posts: 455
Joined: Sun Jul 10, 2011 7:48 pm
Location: NorCal/SoCal

by MoPho

Theologian wrote:
Mon Sep 10, 2018 4:42 pm
Growing up here in the Northeast, we all had to learn how to "pump" your car brakes in the winter before ABS became standard on cars. In fact, we learned to turn "into" the direction the car is sliding (against intuition) to gain traction should the wheels locked up on snow or ice. I don't think I've ever done that on a bike, the window for reaction is really small. I wonder if ABS would work on bike.

Also grew up in the Northeast and learned to pump the brakes. I have similarly pumped the [rear] brake many a time on my road bike when having to make hard stops, particulalry when I was using rim brakes. Can't recall having to do it since going to disc.
Usually if you've locked the front wheel, you've already gone down LOL

dvq
Posts: 134
Joined: Mon Sep 25, 2017 1:36 pm

by dvq

Theologian wrote:
Mon Sep 10, 2018 4:42 pm
Growing up here in the Northeast, we all had to learn how to "pump" your car brakes in the winter before ABS became standard on cars. In fact, we learned to turn "into" the direction the car is sliding (against intuition) to gain traction should the wheels locked up on snow or ice. I don't think I've ever done that on a bike, the window for reaction is really small. I wonder if ABS would work on bike.
Works _really_ well on motorcycles.

by Weenie


dvq
Posts: 134
Joined: Mon Sep 25, 2017 1:36 pm

by dvq

MoPho wrote:
Mon Sep 10, 2018 6:37 pm

Also grew up in the Northeast and learned to pump the brakes. I have similarly pumped the [rear] brake many a time on my road bike when having to make hard stops, particulalry when I was using rim brakes. Can't recall having to do it since going to disc.
Usually if you've locked the front wheel, you've already gone down LOL
I think that's one of the things I see that ABS on motorcycles does well -- allows you to retain the ability to stay upright as well as stopping in a shorter distance. Normally you'd just lock the front wheel and fall over as the bike falls over.

https://www.youtube.com/watch?v=dJ_UkAFW6cA

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