Advantage of Disc Brakes?
#26
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From: Pittsburgh, PA
Bikes: '96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '20 Surly Midnight Special, All are 3x10. It is hilly around here!
#27
Senior Member
Joined: May 2013
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From: SF Bay Area
Bikes: Bianchi Infinito (Celeste, of course)
One minor advantage of disc brakes is that the brake force is more consistent.
Rims always have minor variations and are never perfectly true. As a result rim brakes tend to grab a tiny bit in certain spots. As a result you can't get quite as much power before locking up.
Hydraulic discs also respond faster, meaning it's easier to recover from being over the limit.
Mechanical discs brakes aren't really any better than a modern dual pivot rim brake. Both are basically limited by the flex in the cables. The discs will be better in the rain.
The difference between brakes is basically only noticeable when you're riding near the limits.
Rims always have minor variations and are never perfectly true. As a result rim brakes tend to grab a tiny bit in certain spots. As a result you can't get quite as much power before locking up.
Hydraulic discs also respond faster, meaning it's easier to recover from being over the limit.
Mechanical discs brakes aren't really any better than a modern dual pivot rim brake. Both are basically limited by the flex in the cables. The discs will be better in the rain.
The difference between brakes is basically only noticeable when you're riding near the limits.
#28
FLIR Kitten to 0.05C
Joined: Sep 2014
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From: Lincoln, Nebraska
Bikes: Roadie: Seven Axiom Race Ti w/Chorus 11s. CX/Adventure: Carver Gravel Grinder w/ Di2
#29
Banned.
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The problem with these things is that the comparisons are rarely apples to apples. High end disc brakes, either hydro or mech are worlds better than high end rim brakes, IME. There is a lot of overlap at the mid/low end for regular riding. Rain/dirt and discs are superior across the board.
One major thing is that disc brakes allow significantly better braking with wide tires. Compare even the lowliest mechanical disc brake to a long reach caliper and the former is significantly better in all conditions.
Disc brakes are also completely insulate the wheel-set from structural wear. I've seen the stock pads on rim brakes destroy a rim, ridden only in dry weather, in less than 5,000 miles. We're talking rim thickness that went from 1.7mm to 0.4mm in half a season - rim was toast and it was pretty expensive to replace.
The ejection issue seems to be limited to older models - current production is almost entirely thru-axle or forward facing drop outs. I've had the QR loosen but never had a wheel eject and it's pretty scary but just another thing to be checked during pre-ride. In my case the lawyer lips kept the wheel in place for almost 6 hours of riding with it loose enough to shift every time I braked, I just didn't notice.
Mine was on a poorly designed Soma fork that STILL has downward facing dropouts for some stupid reason.
Here's a great article and graphic:


https://cyclingtips.com/2015/10/road...axels-but-why/
Anyway, with the exception of my C&V fixed gear all my bikes are disc. I ride mountain bikes a lot, I ride in the rain and at night a lot and I like to switch between fat 650b and skinny 700c so discs work great for me.
One major thing is that disc brakes allow significantly better braking with wide tires. Compare even the lowliest mechanical disc brake to a long reach caliper and the former is significantly better in all conditions.
Disc brakes are also completely insulate the wheel-set from structural wear. I've seen the stock pads on rim brakes destroy a rim, ridden only in dry weather, in less than 5,000 miles. We're talking rim thickness that went from 1.7mm to 0.4mm in half a season - rim was toast and it was pretty expensive to replace.
The ejection issue seems to be limited to older models - current production is almost entirely thru-axle or forward facing drop outs. I've had the QR loosen but never had a wheel eject and it's pretty scary but just another thing to be checked during pre-ride. In my case the lawyer lips kept the wheel in place for almost 6 hours of riding with it loose enough to shift every time I braked, I just didn't notice.

Mine was on a poorly designed Soma fork that STILL has downward facing dropouts for some stupid reason.
Here's a great article and graphic:


https://cyclingtips.com/2015/10/road...axels-but-why/
Anyway, with the exception of my C&V fixed gear all my bikes are disc. I ride mountain bikes a lot, I ride in the rain and at night a lot and I like to switch between fat 650b and skinny 700c so discs work great for me.
#30
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Joined: Mar 2008
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The big thing is the self-unscrewing that happens.
Once the q/r begins to slip, even once, the acorn nut unscrews rather rapidly.
It doesn't take long before the q/r becomes slack enough to slide over even rather deep lawyer lips.
The chance the rider has to notice the wheel losing alignment during braking before ejection is rather small.
Sure, IF you ALWAYS use a rigid enough skewer, and ALWAYS close it hard enough, THEN the current design works.
But considering how easy it would have been to avoid, it's kinda embarrassing and annoying that the industry settled for such a poor design.
It's a critical assembly, and it's designed in a way that allows it to fail at an easily foreseeable operator/equipment error.
#31
FLIR Kitten to 0.05C
Joined: Sep 2014
Posts: 5,331
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From: Lincoln, Nebraska
Bikes: Roadie: Seven Axiom Race Ti w/Chorus 11s. CX/Adventure: Carver Gravel Grinder w/ Di2
IMO, there are actually TWO fairly big ifs in that statement.
The big thing is the self-unscrewing that happens.
Once the q/r begins to slip, even once, the acorn nut unscrews rather rapidly.
It doesn't take long before the q/r becomes slack enough to slide over even rather deep lawyer lips.
The chance the rider has to notice the wheel losing alignment during braking before ejection is rather small.
Sure, IF you ALWAYS use a rigid enough skewer, and ALWAYS close it hard enough, THEN the current design works.
But considering how easy it would have been to avoid, it's kinda embarrassing and annoying that the industry settled for such a poor design.
It's a critical assembly, and it's designed in a way that allows it to fail at an easily foreseeable operator/equipment error.
The big thing is the self-unscrewing that happens.
Once the q/r begins to slip, even once, the acorn nut unscrews rather rapidly.
It doesn't take long before the q/r becomes slack enough to slide over even rather deep lawyer lips.
The chance the rider has to notice the wheel losing alignment during braking before ejection is rather small.
Sure, IF you ALWAYS use a rigid enough skewer, and ALWAYS close it hard enough, THEN the current design works.
But considering how easy it would have been to avoid, it's kinda embarrassing and annoying that the industry settled for such a poor design.
It's a critical assembly, and it's designed in a way that allows it to fail at an easily foreseeable operator/equipment error.
#32
Senior Member
Joined: Feb 2009
Posts: 6,660
Likes: 177
Oh man! Now I have to check to see how the front wheels of my Catrike are held on.
I can tell you from personal experience that the front wheel disc brakes have PLENTY of stopping power to lift the rear wheel off the ground. It won't endo, though, because the sprocket bash guard hits the ground to stop it. Might it eject a front wheel? I honestly don't know. I've never needed to take one of the front wheels off. If I have a puncture, I just roll the trike up on it's side.
I can tell you from personal experience that the front wheel disc brakes have PLENTY of stopping power to lift the rear wheel off the ground. It won't endo, though, because the sprocket bash guard hits the ground to stop it. Might it eject a front wheel? I honestly don't know. I've never needed to take one of the front wheels off. If I have a puncture, I just roll the trike up on it's side.
Your Cattrike, if it's like my friends has a through axle. He sometimes is on a different plant and has ridden with a loose QR and never had an ejection.
#33
Senior Member

Joined: Aug 2005
Posts: 1,224
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From: New Hampshire
Bikes: Niner RLT 9 RDO, Niner RLT9 Alloy
The ejection issue seems to be limited to older models - current production is almost entirely thru-axle or forward facing drop outs. I've had the QR loosen but never had a wheel eject and it's pretty scary but just another thing to be checked during pre-ride. In my case the lawyer lips kept the wheel in place for almost 6 hours of riding with it loose enough to shift every time I braked, I just didn't notice. 
Mine was on a poorly designed Soma fork that STILL has downward facing dropouts for some stupid reason.

Mine was on a poorly designed Soma fork that STILL has downward facing dropouts for some stupid reason.
One downside is that I find wheel mounting slightly more awkward with the forward dropouts. I think it's because the angle of the dropout kind of pushes the wheel forward as you're lowering the fork down onto it.
#34
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Joined: Mar 2008
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A front-mount caliper and the design becomes fail-safe. Even thru-axles would benefit. With both ride and brake forces acting in much closer alignment it'd be far easier to keep the front wheel accurately in place.
#35
Occam's Rotor
Joined: Jul 2013
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Unfortunately, that isn't true.
Although my disc brake wheel moves around in the fork, it hasn't come out. Yet. I bought some better, internal cam quick releases, like you recommended. Enve's newer version of their CX disc fork is thru-axle, but the one I got in 2014 is not. (It looks like Figure 4 in the above post.) It popped out of my roof rack once. The fork is sprung instead of having lawyer tabs, but that I found can cut both ways.
Although my disc brake wheel moves around in the fork, it hasn't come out. Yet. I bought some better, internal cam quick releases, like you recommended. Enve's newer version of their CX disc fork is thru-axle, but the one I got in 2014 is not. (It looks like Figure 4 in the above post.) It popped out of my roof rack once. The fork is sprung instead of having lawyer tabs, but that I found can cut both ways.
Last edited by Cyclist0108; 02-12-17 at 12:26 PM.
#36
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Joined: Aug 2005
Posts: 1,224
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From: New Hampshire
Bikes: Niner RLT 9 RDO, Niner RLT9 Alloy
My argument isn't with QRs, it's mainly with the decision to put the caliper on the rear of the fork.
A front-mount caliper and the design becomes fail-safe. Even thru-axles would benefit. With both ride and brake forces acting in much closer alignment it'd be far easier to keep the front wheel accurately in place.
A front-mount caliper and the design becomes fail-safe. Even thru-axles would benefit. With both ride and brake forces acting in much closer alignment it'd be far easier to keep the front wheel accurately in place.
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