Road Bike, Cycling Forums banner
1 - 13 of 13 Posts

·
Registered
Joined
·
17 Posts
Discussion Starter · #1 ·
Hi guys , I just purchased a second hand set of RTS R50 carbon clincher wheels and I noticed that there is brake pulse as I am coming to a stand still on the bike . Currently am using KoolStop brake pads . The thing is I do not know if I should be worried about this , some say that its a common problem with carbon clinchers and some say its not . At speed and under heavy braking theres not much to be felt but as I have noticed it happens just as Im coming to a stop .Can anyone help shed some light on this as I m really confused . Thanks again guys .
 

·
Registered
Joined
·
1,298 Posts
Have you checked that they're perfectly true? I've been having trouble with my Zipp 303s in that one of the non-drive side spokes keeps loosening up and the wheel goes out of true. I can tell when it's happened because the rear brake starts pulsing when I get close to a complete stop.
 

·
Registered
Joined
·
17 Posts
Discussion Starter · #3 ·
Carbon clincher brake pulse.

Hi, I'm having the same pulse issues as I come to a stop on the rear wheel too. Switched to Swisstop yellows but I still feel it. I do notice the braking surface on the rim is not as even as an aluminium rim but from what I've read on numerous forums is that it's expected of carbon wheels. A lot of conflicting views on this so am not sure what to think. Have been riding them for quite awhile now and I must say they deliver stiff for the climbs and so far good on the descents. The thing is the brake pulse and the uneven brake surface keeps bugging me in a sense that if it's normal or not. Checked the spokes like you said and all normal. thanks for the input dude.
 

·
Recycle King
Joined
·
870 Posts
Check to make sure your brakes are center on the wheel. Also, did you toe-in your brake pads? If not, that could be the cause as in my case a month ago after I switch over from alloy rims to carbon clinchers. Do a search on squeaky brake pads as that topic has been discussed before.
 

·
Recycle King
Joined
·
870 Posts
Also, make sure your braking surface is clean on your wheel and clean on the pad. I was told from another thread that could be the cause for pulsing. Use a scrub pad to clean.
 

·
Registered
Joined
·
31 Posts
As mentioned by roadrunnerL, make sure you toe-in the pads ever so slightly. It took me two attempts to get the pads positioned correctly on my zipp wheels before I got rid of the shudder and squealing. All I heard today was the 'raspy' sound of the pad doing it's job :)
 

·
Registered
Joined
·
17 Posts
Discussion Starter · #10 ·
Hi There , have noticed that my carbon clincher rear wheel's brake track surface is a slightly wavy or uneven ,is this normal for a carbon clincher ? Dont seem to be able to get definitive answer to this . Would be really helpful if you could shed some light on this .Thanks for your help bro.
 

·
Registered
Joined
·
41 Posts
Smooth carbon braking needs: consistent carbon rim thickness. Clean brake tracks with even Friction around the entire rim. Clean brake pads without much gunk or dust in the grooves. Clean dry conditions ( not like yesterdays gran fondo ny)

Carbon brake tracks wear down and could pulse after much use. As you use the wheels the thickness gets worn of and the rim becomes uneven.

The thickness of the carbon rim brake track is dependent on quality lay-up and can vary in thickness along the rim. Cheap rims suffer from this.

Carbon specific pads also wear out - they are meant to shed material quickly to dissipate heat. When they wear poorly they hold inconsistently on the rim. The front of the pad might be thinner than the rear if they are angled poorly.

Also, as pad material is deposited on the rim, friction varies along the brake tracks. The brakes hold and release as the wheel goes round. The rim should be cleaned.

Basically all the things we are used to with aluminum rims and rubber pads are gone. It's like we started over with wheels and brakes.
 

·
Registered
Joined
·
17 Posts
Discussion Starter · #12 ·
Thanks for the info Bro. You are right though nothing compares to the braking efficiency of an aluminium rim. Well I guess it comes with the territory. Thanks again for the info dude, much appreciated mate.
 
1 - 13 of 13 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top