Alto Cycling, in conjunction with Spark Wheel Works, recently completed a destructive braking heat test that shows carbon clinchers by Zipp, ENVE, Mavic and others failing in spectacular fashion.
The test planned to run each of the wheels for 20 minutes with the brake pulled onto the rim at 7lb of force. If the carbon wheel survived that period, the braking was increased to 9lb and test continued for another 20 minutes. Alto tested carbon clinchers from Mavic, ENVE, Zipp, Knight, Boyd, FSE, Bontragerand Roval as well as the brand’s own product.
The speed was consistently higher on the Altos, could indicate poorer braking performance? The lower temperature would lead to the same conclusion. That braking energy needs to go somewhere, and of not in heat, I don’t know in what.
The Zipp also achieved lower temp’s, but failed at around 300s. You are right that the ‘energy’ has to go somewhere – it may not all be concentrated on the Altos braking surface, the heat may be dissipating in other parts of the rim, leading to a better performance in fatigue…
I was thinking the exact same thing.