Rim brakes gradually erode the sidewalls of the rim

Rim brakes gradually erode the sidewalls of the rim

The effect of rim brakes is almost as subtle as spoke fatigue. If the brake track has a surface finish (such as black anodising), then riders might notice when it disappears, or if it is polished, the black marks that slowly appear. Both are of little consequence to the integrity of the rim, but they are the first signs of the gradual erosion that is caused by the brake pads.To get more news about Carbon Wheels, you can visit zpebicycle.com official website.

Over the course of many months, years even, the sidewalls of the rim will become concave as the pads scrub away at the material. It’s an inevitable by-product of rim-braking that affects both alloy and carbon rims. The combination of rain and dirt/debris will enhance the abrasive effect of the brake pads to accelerate the process while soft-compound brake pads (eg. Swissstop BXP) can be used to slow it down, however, the only way to eliminate it is to switch to disc brakes.

For riders using rim brakes, it’s important to monitor the brake track of the wheels. Rubbing a finger over the track will reveal any concavity and a straight edge can be used to gauge how deep the concave is.

Rim walls are typically less than 2mm thick, so any concavity approaching 1mm is very significant (and worrying), especially for clincher rims. That’s because the hooks of the rim will get weaker as the brake track is worn away. There will come a point when sidewalls will flare from the pressure within the tyre. Tears will appear in the brake track and one or both hooks will fail, leading to a blowout for the tyre.

It is difficult, if not impossible, to anticipate when this will happen. Some rim manufacturers position wear-indicators in the brake track, recommending that the rim be replaced once those indicators are no longer obvious. In the absence of such indicators (typical for carbon rims), owners must decide the risk for themselves.The hubs and wheel bearing are also subject to wear and tear, where the biggest threat comes from the gradual accumulation of dirt and debris and the ingress of water. The former will have an abrasive effect on the balls and races while the latter will promote rust.

Regular hub maintenance will go a long way to prolonging the life of the bearings, however the eventual demise of these moving parts is inevitable. For those hub using cartridge bearings, the entire unit can be replaced when balls or races are damaged. Similarly, cup and cone hubs can be overhauled with new parts (cones and bearings) though not all have replaceable cups, so once pitted, the hub will have to be replaced.

Any play in the bearings or hub axle can be indicative of wear, so it shouldn’t be ignored when it appears. Similarly, any roughness or catches in the bearing-action when the axle is turned by hand is enough to warrant a service so that all of the parts can be cleaned and inspected to accurately determine the cause of the problem.