Carbon rims, squeeling and burning noise

huskie69

Hi all

I recently got hold of some carbon rims (with carbon braking surface).

I couldn't fit the provided brake pads/block into my exisitng brake shoes (Ultegra 6800). Although they were very similary shaped, they were a way too tight to push in the remaining 5-7mm. Additionally, there was no recess for the "grub screw" which seems to hold the original pads in place. They also appeared to be made out of the same material (though I could be wrong).

I did a tiny bit of reading (http://bicycles.stackexchange.com/questions/23605/are-all-the-ultegra-brake-pads-the-same) and it seems that the pads supplied with the Ultegra groupset (R55C4) are compatiable with both aluminium and carbon brake tracks. So off I went on a quick ride.

I'm not a light rider by any means (110kg) but I'm not constantly on the brakes. I get up quite a but of momentum so obviosuly it takes a lot more force to slow me down than lighter cyclists. II came to the first set of traffic lights and had to slow down. There was an almighty squeel from both sets of brakes followed by a really intense burning smell. While I was stopped, I touched the rear braking surface to find it was quite warm. Keep in mind this was the first time I'd slowed to a stop with these brakes, on a flat road. Minimal effort. I completed the rest of the ride with caution, only slowing when I really had to.

I'm concered the pads I'm using aren't suitable for my rims. I don't want to take these wheels out again using the pads I've got for fear of delaminating the brake track.

Are intense noises and smells normal when riding on carbon wheels? Is it something I have to get used to? Or is it that I really am using the wrong kind of pad and a proper pad will alleviate these problems (or certainly what I feel to be a problem!)?

mamba80

R55C4 are for alloy rims only.

R55C or R55C-1 for Carbon.

google shimano tech docs, then ultegra/BR6800/dealer manual (DM)

fwiw i ve found the campag Red pads to be very good, though if you direct mount brakes, they dont have the cut out in the right place for the 6810 pad holders on the front brake.

huskie69

Thanks mambo80.

I've seen RC55 blocks for both ceraminc and carbon rims. The R55C-1 appears to be made to alu rim. They all look the same! Really confusing. All the brands should start adding dyes to their pads so you know what compound they are at a glance.

I'm considering getting hold of new combination shoes and pads so I can quickly swap them over when I revert back to the normal aluminium rims (quickerthan swapping out the pads each time anyway).

Any recommendations (that won't cost a small fortune?!)

cougie

Just wait until you try them downhill in the wet.....

huskie69

cougie wrote:

Just wait until you try them downhill in the wet.....

I live in Wales, so if I'm not going downhill in the wet, I'm going uphill.... in the wet!

cougie

What made you choose all carbon rims?

huskie69

cougie wrote:

What made you choose all carbon rims?

The price

trailflow

If your using your old alu pads with the new carbon wheels, the old pads will be contaminated with aluminium particles. So that could be exacerbating the noise and heat build up. If you keep riding them i reckon you will destroy your carbon rim braking surface in no time.

Before you re-use the old alu pads with the alu rims. Give them a good clean with soap,hot water and a scourer and then a light sanding or filing of the surface. Otherwise any carbon/basalt stuck in them could re-contaminate your alum rim.

If the carbon wheels are chinese ebay jobbies. The pads that are included with those are crap. Mine also squeeled and heated up rapidly. Seriously bin them.

And buy some of these. They will instantly make a massive improvement to braking performance,noise and heat.
http://www.wiggle.co.uk/lifeline-perfor ... pack-of-4/

Another tip. When setting them up. Position the pad holders so the pads contact the rim at the bottom of the brake track. This will keep the heat build up away from the tyre and help lessen the chance of overheating/blowout/delamination.

huskie69

trailflow wrote:

And buy some of these. They will instantly make a massive improvement to braking performance,noise and heat.
http://www.wiggle.co.uk/lifeline-perfor ... pack-of-4/

Another tip. When setting them up. Position the pad holders so the pads contact the rim at the bottom of the brake track. This will keep the heat build up away from the tyre and help lessen the chance of overheating/blowout/delamination.

Perfect, thanks Trailflow - a much better price than some of the other pads I've seen. Hopefully arriving in the next few days.