Hyrdaulic Disk Brakes

Discuss light weight issues concerning road bikes & parts.
GothicCastle
Posts: 110
Joined: Mon Jul 04, 2016 1:52 am

by GothicCastle

Cheetahmk7 wrote:Both really. You can't radially lace a disc brake hub for instance and that means a different hub design.


You can radially lace the non-disc side if you want.

But all of these arguments are silly. The lacing pattern doesn't appreciably affect aerodynamics, the number of spokes does.

If a six watt difference is significantly significant to your riding, it doesn't matter what wheels you use. You need to get for before you worry about such things.

Cheetahmk7
Posts: 69
Joined: Sat Aug 20, 2011 2:09 am

by Cheetahmk7

GothicCastle wrote:
Cheetahmk7 wrote:Both really. You can't radially lace a disc brake hub for instance and that means a different hub design.


You can radially lace the non-disc side if you want.

But all of these arguments are silly. The lacing pattern doesn't appreciably affect aerodynamics, the number of spokes does.

If a six watt difference is significantly significant to your riding, it doesn't matter what wheels you use. You need to get for before you worry about such things.


True.

And disc equipped wheels usually have more spokes. For instance the disc Zipp 404 has 6 more spokes.

I'm happy for you that you have power to burn.

fogman
Posts: 774
Joined: Fri Oct 30, 2009 10:36 pm

by fogman

I haven't heard anything recently about whether the UCI intends on lifting the disc brake ban again.


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It's all downhill from here, except for the uphills.

pushstart
Posts: 441
Joined: Sat Jun 16, 2012 3:12 am

by pushstart

Cheetahmk7 wrote:The brake tracks on the FLO30 wheels are definitely not vertical. From the Flo website:
The FLO 30's brake track starts at 24.00mm and reaches 25.82mm at the bottom.


I ride Flo30s too. I built them as disc-brake wheels, though. While the brake track is not perfectly flat, it is obvious looking at it they are still constrained by the brake pads. Compare to a Aileron or others of the newer disc-only rims. Those shapes clearly wouldn't work with rim calipers.

Obviously rim calipers are a constraint and removing that constraint opens up flexibility. Everyone in the industry has said that when asked.

But arguing over these hypothetical 3-6watts is silly. Look at a complete bike with modern, flat-mount brakes. If Specialized says it is a few seconds difference in the 40k/40kmph between an aero rim-brake bike and aero disc-brake, then that is probably the best / most-relevant apples-to-apples data here.

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mpulsiv
Posts: 1021
Joined: Mon Mar 24, 2014 9:17 pm

by mpulsiv

fromtrektocolnago wrote:I don't like the noise disc brakes make.


QR's is the root cause of noise due to marginal misalignment, right? I read that thru-axle remedy the noise issues.
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

MichaelB
Posts: 435
Joined: Tue Apr 22, 2008 4:31 am

by MichaelB

:lol: :lol:
I find many of the posts rejecting discs due to weight & aero a bit funny. Weight CAN be an issue, but the difference is not that much. That said, this is WW.

The weights are coming down and the aero stuff is real;ly lineball. If aero was really king, why do pro's have big bushy beards, flapping jerseys, dangling chains etc ...

ANYWAY, just got back from 2 weeks in Italy & France, and I can honestly say the discs (R785 levers and Zee calipers) were the ducks nuts :mrgreen:

Some of the descents (Passo Fedaia to Caprile, Umbrail & Il Monticello) would have been more interesting on rim brakes. Long descents were easy due to the 99% 1 finger braking.

The discs didn't slow me down up the hills (I'm not a small guy) but they certainly died it well going down !!! Same feel & power at the top and bottom, wet or dry, hot or cold.

Discs are the way fwd imho, but if you are happy with your rim brakes, then great too :beerchug:

tomee
Posts: 112
Joined: Thu Oct 16, 2014 8:52 am

by tomee

MichaelB wrote:ANYWAY, just got back from 2 weeks in Italy & France, and I can honestly say the discs (R785 levers and Zee calipers) were the ducks nuts :mrgreen:


What are the differences between the r785 or r805 calipers vs the Zee's?
i know Zee's are for mtb downhillers, do they run dual calipers?

fromtrektocolnago
Posts: 992
Joined: Sat Dec 07, 2013 10:15 pm

by fromtrektocolnago

mpulsiv wrote:
fromtrektocolnago wrote:I don't like the noise disc brakes make.


QR's is the root cause of noise due to marginal misalignment, right? I read that thru-axle remedy the noise issues.



My set-up is thru-axle
Colnago C-59 (Dura Ace)
Firefly(Ultegra)
Trek 5200(ultegra)

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mpulsiv
Posts: 1021
Joined: Mon Mar 24, 2014 9:17 pm

by mpulsiv

fromtrektocolnago wrote:
mpulsiv wrote:
fromtrektocolnago wrote:I don't like the noise disc brakes make.


QR's is the root cause of noise due to marginal misalignment, right? I read that thru-axle remedy the noise issues.



My set-up is thru-axle


Noisy even in dry condition?
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

MichaelB
Posts: 435
Joined: Tue Apr 22, 2008 4:31 am

by MichaelB

@ tomee

785 & 805 are both 2 piston calipers. 785 is the post mount, and 805 are the new Ultegra level flat mount.

Zee are the 4 piston MTB caliper (same size etc as Saint). Main reason for using the Zee is the bigger pad area, hence greater heat dissipation, longer pad life and more braking power. Still get brilliant modulation.

One added benefit was the hose routing suits my Volagi Liscio better than the R785 (banjo fitting) or BR785 (inline threaded fitting) because of where the fluid entry is on the caliper.


Anyone want a set of unused & unmounted BR785 calipers for cheap ? :lol:

PhilippCX
Posts: 54
Joined: Tue Jul 19, 2016 9:13 pm

by PhilippCX

mpulsiv wrote:
fromtrektocolnago wrote:
mpulsiv wrote:
fromtrektocolnago wrote:I don't like the noise disc brakes make.


QR's is the root cause of noise due to marginal misalignment, right? I read that thru-axle remedy the noise issues.



My set-up is thru-axle


Noisy even in dry condition?


I also run discs with thru-axles and they are indeed noisy in wet conditions. Same story on my CX bike with QRs and mechanical disc brakes.

Misalignment does not cause the squealing. My understanding is that it is caused by the ratio of static and dynamic friction coefficients of brake pads and disc surfaces.
Sintered metal pads are the worst in this respect. Btw. it's the same issue with cars. I had sintered metal pads on my previous sports car and they were squealing like crays when cold.

tomee
Posts: 112
Joined: Thu Oct 16, 2014 8:52 am

by tomee

MichaelB wrote:@ tomee

785 & 805 are both 2 piston calipers. 785 is the post mount, and 805 are the new Ultegra level flat mount.

Zee are the 4 piston MTB caliper (same size etc as Saint). Main reason for using the Zee is the bigger pad area, hence greater heat dissipation, longer pad life and more braking power. Still get brilliant modulation.

One added benefit was the hose routing suits my Volagi Liscio better than the R785 (banjo fitting) or BR785 (inline threaded fitting) because of where the fluid entry is on the caliper.


Anyone want a set of unused & unmounted BR785 calipers for cheap ? :lol:


interesting. I didnt know you could use mtb brakes with road. In the end i guess if you have the right line connection and mounts then it shouldnt matter.
Have you got any pics? im intrigued by this setup.

Broady
Posts: 266
Joined: Thu Jan 03, 2013 5:02 pm

by Broady

I run XT on the front, no problems at all. No noise or anything, no flex due to the QRs, all the online complaints are usually from people who have never actually used them.

Image

Brus
Posts: 38
Joined: Mon Apr 25, 2016 1:36 pm

by Brus

i think XT and R785 are completely the same except of "XT" logo.

I have R785 right now and i´m coming back to rim brakes with my next bike. i have 10k km of experience with disc brakes, i understand people who like them. But it´s not for me.

fromtrektocolnago
Posts: 992
Joined: Sat Dec 07, 2013 10:15 pm

by fromtrektocolnago

I'll be riding my disc brake bike more in the winter. Disc brakes have their uses and applications, but the proponents over-state the need. I ride my caliper bike far more than my disc bike
Colnago C-59 (Dura Ace)
Firefly(Ultegra)
Trek 5200(ultegra)

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