I bought them a few weeks ago. Altogether and with all the RR data out there it will hopefully help a client of mine save around 20-24w on his TT bike (pulleys, chain, tires, and glue job).
Open question here, as I'm just curious... I've always been told that at speed you spend about 90% of your effort on wind resistance (even a professor in a sports physics class at the university told me so when we talked about aerodynamics in sports), and then we talked about some 35km/h so fairly slow...
Let's just for the sake of argument say you still loose 90% to wind resistance at 45 km/h, some 450 watts or so, right? ...can you actually shave 24 watts out of those 45 watts (your 10% non-wind resistance)? It sounds so unlikely that you could easily cut all mechanical resistance in half?
Please enlighten me?
I cannot answer your question in the way you posed it but his position has been optimized using roll down tests as best we can.
RR data shows that a switch from his old tires to new tires should net around 12-15w depending on how good his glue job is.
The new chain should save another 6w.
Properly cleaned and lubricated spindles another 1-2w.
Jockey wheels we're unsure of.
So if he had not optimized those things he'd have that many more lost w in terms of friction and RR. Also changed his helmet, which helped in the roll down tests. If we want to believe Castelli his new skin suit should add something I've not included in these calculations.
So if you add it up for a pro:
Oversized pulleys: 2.4w
Optimized chain: 6w
Ceramic BB: 2w
Proper width tires with appropriate glue job: 12w
Simply covering these bases nets them 22.4w over competitors that do not do these things. It might not be this much in practice, but it makes sense as to why they bolt on Berner derailleurs on special days, re glue tires and match them to the rim width, and pursue such small gains.
Don't take me too seriously. The only person that doesn't hate
Froome.GramzFailed Custom Bike