Hi Waldo, thanks for your bright reply. The numbers you posted make more sense! The graph you posted with the 303 vs 404 with 23mm and 25mm tyres is very handy! The rims/tyres in that graph are clinchers I presume?
I expected that the 303 with a 25mm was doing better. But my conclusion from your graph is that the 404 is always faster. Even a 404 with 25mm is can beat a 303 with 23mm tyre at some yaws. Is it true that the difference of the 404FC vs 303FC is only one watt? From the graph it looks more?
What combination do you think can take the abuse of rough roads / cobbles during a road race beter: A 404FC with 25mm GP4000S or a 303FC with 23mm GP4000S?
The graph brings me to the same question you have, 10 grams of drag is approximately one watt. Nowhere in the graph we can see the 404 getting as closed as 10 grams compare to the 303 with the same tire.
I have 808 firecrest carbon clincher on my TT bike (they are absolutely fabulous !) and 303 carbon clincher, I went with 303 over 404 exactly because riding with 23mm tires on my road bike I thought the aero advantage of the 404 would be close to none (404 would still be faster with 21mm but I don't use such small size for road as we have rough roads where I live). If the graph is correct Waldo, I really wished I went with 404 !!! It would also have been a better match to have the 404 so that when weathier is windy I could use 808 rear with 404 front on the TT bike.
Waldo, please enlighten us, why 1 watt in catalog and much more showing on your graph ?