This makes sense if you are testing braking effectiveness, but their intent was not to see which rim stopped best, either initially or over time, It was rather a test of which rim would not fail violently under ham fisted and unsafe braking.
The safest riders will brake hard before corners and accelerate again, they may brake hardest, but they are unlikely to put their rims at risk because they get back off the brakes and accelerate after the turn (I suppose a very long straight decent or a huge group ride like a fondo in which high speed until the corners is unsafe or impossible could/would make that less true). My understanding is that carbon failure is more likely among folks more uncomfortable descending who continually drag their brakes over long periods until their rims delaminate and can fail catastrophically. This test may not be a perfect representation of that type of abuse (there are totally fair critiques of the test above, especially the critique about using a common brake pad) but to suggest it does not fairly "test braking" ignores the point of the test and article, of course it doesn't.
I did read the whole linked article, but didn't watch the longer video. If, as stated above, temperature drops after 300 seconds (5 minutes right?) by that point hadn't the Altos already outlasted all but one of the other wheels. Overheating clearly negatively impacts brake function, and it delaminated the Altos too, but they didn't fail catastrophically. It won't make me rush out and buy any, I'm 6'3" and 220, I would never own carbon rim brakes, but it seems like a valid thing to test for, even if the test could and should be improved.
Quote:
Originally Posted by muz
As an engineer, this strikes me as a bogus test. The way you test a brake system is this: You use a heavy flywheel to drive the carbon wheel under test. Bring it up to test speed, then apply brakes with no additional power added. If a brake system is effective, it will bring the wheel to stop quickly. Repeat until failure, increasing flywheel weight if necessary.
The obvious fallacy in the cited test is that efficient wheels which can apply a lot of braking force will be stressed more than wheels with slippery brake tracks. Which wheels would you choose going down an Alpine pass in the rain?
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