Originally Posted by
Jancouver
Just want to share my wheel cover experience. Did two TTs on the same course two weeks apart. Almost identical weather conditions, pretty much the same power output and same time. First TT was done on 45mm carbon clinchers, the second TT was done on same wheelset with a rear wheel disc covers from Wheelbuilder. To my disappointment the disc cover made no difference over 20K TT.
Just saying ....
On a 20k TT the expected performance gain of a disc wheel versus a 45mm carbon wheel is, let's say, between 10 and 30 seconds.
You say the weather was "almost identical" and the power was "pretty much the same".
Slight differences in wind or power or power spread might have seriously in fluenced your time here, making the disc come out as having no gain.
You can't just compare one ride to another.
Do the same course at least 5 to 10 times both with and without the covers and then take the average difference ... even then there'll be quite a margin of error but at least a lot less
