Mavic Open Pro Ceramic Rim £81.95 each

Well into a particularly wet and mostly warm winter, RCUK can now offer a full assessment of Mavic’s Open Pro Ceramic clincher rim.

There’s no particular need to modify our earlier appraisal, which gives a good idea what to expect. However, one or two aspects of ceramic rim performance bear careful scrutiny. First of them is what happens to what is an expensive investment in the event of an impact.

Two of my ceramic rims, both on front wheels, have now received dents, one from hitting a kerb and the other the sharp edge of a manhole cover. In both cases the ceramic coating immediately adjacent to the site of the impact flaked away to leave a rough indent. Luckily, both rims remained perfectly useable. Although dented inwards, the braking surface of both rims retained a narrow strip of ceramic that kept it a constant width, avoiding the snatch under braking that would have consigned either to the bin.

In this I was very lucky; a bigger or differently shaped dent could have wrecked £80 worth of rim plus building costs. Given that both rear rims remained undamaged and that it is usually the rear that wears out first from heavy winter use, there is a good case for fitting a ceramic rim to the rear wheel only, should cost be a deciding factor.

Standard Shimano (Dura Ace) rubber blocks work well in the dry on these rims. If used for extended periods of dry weather riding, the rim acquires a kind of polish to its braking surfaces. This affects wet weather braking quite markedly until it has worn off, which takes about 10 miles of urban riding in heavy rain. Thereafter, the rim offers exceptional retardation in the wet, but polishes up again after a few miles in the dry.

The loss of wet weather braking power in a polished ceramic rim is not dangerous, inasmuch as the brakes will still stop the bike with a good squeeze. However, there is a considerable difference between the dry and immediate wet performance of the polished rim that might catch out the unwary user.

The wear rate of standard brake blocks is minimal in both wet and dry. I wore a pair of rear blocks close to the pad before fitting a ceramic rim last year. Since then the blocks have not worn any further, and might well last another winter before needing replacement. Since brake blocks are expensive and usually last no more than 2000 miles in all-conditions riding, this goes some way to offsetting the high initial cost of the rim.