Brake track too smooth - roughening.

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NiFTY
Posts: 1493
Joined: Sat May 26, 2012 11:26 pm

by NiFTY

Hi guys, after some advice.

I have a set of Roval CLX40s. They have a uni-D brake tract which initially had a texture on it. The brake track has now become mirror finished and smooth as. This is obviously affecting braking performance with the recommended swissstop black prince pads.

I have tried to deglaze the tracks with a scotchbrite pad and some isopropyl alcohol and have sanded the pads. Still pretty poor brake power. Have talked to local LBS and specialized dealer but they said i have tried everything they know of. The wheels were bought second hand and hence no warranty, which is fine, no arguments with LBS who were helpful.

BUT, can anyone lend any of their experiences in how to add some bite back to the brake track? I assume roughening it somehow would work but not sure how to accomplish this evenly.

Thoughts?

Thanks in advance, wise sages of weight weenies.
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ITTY
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by ITTY

I may be wrong, but it seems like a rough brake track won't necessarily lead to better performance. I'm thinking along the lines of machined aluminum being the standard for braking surfaces. Seems like cleanliness and pad choice would make a much bigger difference.
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Marin
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Joined: Wed Jan 22, 2014 11:48 am
Location: Vienna Austria

by Marin

Carbon brake track? Try different pads. Apart from the occasional squealing, I'm currently liking SRAM OEM black by Swisstop (non-carbon specific) on my carbon rims - their brake track looks the same as your wheels and is very smooth after descending 70.000 meters this year.

sungod
Posts: 1702
Joined: Fri Dec 24, 2010 9:37 pm

by sungod

yep, i'd also try different pads

if the tracks are mirror finish it sounds like something weird is going on between pad and track

i doubt there's much difference between pad-track friction on a matt/mirror track, for instance on my lightweights the tracks are very smooth, but the sticky pad compound grips like crazy

deek
Posts: 406
Joined: Fri Aug 31, 2012 6:32 pm

by deek

How do the pads look? They might be glazed over. Take some sandpaper to them.

Edit: Missed the part about sanding the pads, whoops. I don't know what to tell you, the black prince pads have been pretty stellar for me.

Valbrona
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by Valbrona

What are you expecting from carbon rims, especially in the wet?

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06SpiceRed
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Location: Boulder, Colorado

by 06SpiceRed

As mentioned above try a different brake pad. I highly recommend Reynolds new Cryo power pad. Its fantastic, especially in the wet for a carbon specific pad. I have used swiss stop yellows in the past and will NEVER EVER use those again. They are loud, they leave marks, and they build up some heat.
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NiFTY
Posts: 1493
Joined: Sat May 26, 2012 11:26 pm

by NiFTY

Valbrona as always your comments are useless. I am not talking about wet weather, i am talking about all braking. As stated above i have another set of carbon rims with the same pads that have done 4 times as far and could stop on a dime.

I will give the reynolds pads a go.

Thanks to the useful responders.
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deek
Posts: 406
Joined: Fri Aug 31, 2012 6:32 pm

by deek

Try swapping wheels or pads with a different bike to see which is causing the issue. Maybe your pads got contaminated with something somehow and sanding didn't get rid of it.

rowdysluggins
Posts: 349
Joined: Tue Apr 27, 2010 2:36 am
Location: Taylosville, Utah

by rowdysluggins

What brakes are your using? That sounds like either a brake caliper or pad issue, and I wouldn't mess with the rims. Try Reynolds pads, or I've heard that Williams Wheels blue pads are good too, but less expensive. You need good calipers and carbon specific pads for to get decent performance from carbon rims.

NiFTY
Posts: 1493
Joined: Sat May 26, 2012 11:26 pm

by NiFTY

Calipers are sram red (1st gen dual pivots)
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racingcondor
Posts: 194
Joined: Fri Aug 27, 2010 4:22 pm

by racingcondor

NiFTY wrote:Valbrona as always your comments are useless. I am not talking about wet weather, i am talking about all braking. As stated above i have another set of carbon rims with the same pads that have done 4 times as far and could stop on a dime.

I will give the reynolds pads a go.

Thanks to the useful responders.


I'd bet they are a different brand wheelset though. I've got an Alu wheelset that brakes poorly in the wet compared to my other wheelsets. It's just different grades of metal / differrent brake sufaces.

As other have suggested I would put it down to brake pad residue building up on the rims and I'd bet both have turned a bit glassy. You have sanded the pads (which is good) but you'll need to swap pads to get rid of the build up and stop it coming straight back.

Butcher
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Posts: 1931
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by Butcher

Smooth texture does not mean you're going to have poor braking. Check your car brakes, they are as smooth as they get. All a textured service will do is tear up your pads. Kind of like sand paper.

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aaric
Posts: 430
Joined: Thu Jun 09, 2011 4:10 pm

by aaric

You could always take a magic eraser to the brake tracks on the wheels. Its pretty safe/low abrasive, and if your brake tracks have some contamination on them, it would likely be take off. Not sure if that's more or less abrasive than a scotch brite pad.

Very fine sandpaper would be an option too, if you can't get your desired results any other way.

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