Braking performance and Ceramic rims



hwttdz

New Member
Sep 28, 2003
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The point: do ceramic rims significantly improve breaking performance?

The long version: I've been riding two bikes lately, a tiagra bike with thousands of miles and a shiny almost new ultegra bike. The brakes on the tiagra bike are awful in comparison. In an attempt to remedy this I have replaced the pads, do my dismay it still doesn't break anywhere near as well. Do I need to break the pads in, wear the surface even to increase surface area? are tektro pads just not good (the shimano ones are steep)? would replacing the brake cable help (it's sort of rusted but I can't really feel any stretch) ? how about lubing the cable? teflon based lube? Is this just going to be a difference between the calipers, and the only fix would be new calipers? The fellow at the bike shop mentioned I had polished my rims by braking, decreased the coefficient of friction of the surface, I'm under the impression that these ceramic coated rims have a greater coefficient of friction. Anybody use them how do they work?
 
Clean, dry aluminum is the best braking surface as it has a good coefficient of friction and it conducts heat well. Ceramic is an insulator and as such, it helps in the wet to dry the braking surface but it can cause brake pad overheating and wear.

Cable friction is a big part of braking performance. Keep cables clean, lubed and corrosion free. Here is where stainless cables help.
 
A few bike shop guys told me that the ceramic rims chew through your pads like crazy, which is why they have really"taken off", sales wise...well, not in Australia, anyway.
 
If you adjust the brakes the proper way, use new brake blocks and clean the brakes completely you can make the oldest Weinmann brake come very close to the most expensive Campa brakes.

The difference between the two is that you have to adjust the Weinmann brakes more often if you want the superior braking.

Make sure you also clean the rims very well.

Carbon rims are knows for bad braking.

Regards, Frank.
 
Ceramic coated rims were introduce to get superior braking performance in the wet. In the dry they are even nastier and as someone pointed out they can overheat and shorten brake pad life. Besides, the ceramic coating does not last long either so pretty soon you'll be braking on bare aluminum. But the point is that one does not need ceramic coated rims to get good brake performance. Aluminum in itself is quite adequate. It could be that your Tiagra calipers are flexing as do your cables or even your levers. The ultegra brakes are beefier and more quality components. Try your rims on your Ultegra equipped bike and check if you experience the same. If not then its not the rims.