I did a 40K TT today and Best Bike Split estimates my CdA at 0.2628.
Oldish Ridley Dean with Zipp 404 Firecrest front, Zipp disc rear. I don’t have a feel for how that number stacks up. I presume it’s a fair number with lots of room for improvement?
Without more data in front of me, that seems on the high side, but quite posssily realistic. That said, using race data often yields a lower CdA number due to passing traffic. Their model does take weather into account, but it’s necessarily coarse grained data.
If you want to look into this yourself, search the forum for ‘platypus’ - there’s a long running thread on performing aero testing and using Golden Cheetah to find out CdA and Crr. Beware though, it’s a bit like entering the rabbit hole 😄.
Thanks. Rabbit hole as in impossible to account for all the variables?
Not impossible 
I meant that once you start looking at aero, you’ll never stop.
I did a 40K TT today and Best Bike Split estimates my CdA at 0.2628.
Oldish Ridley Dean with Zipp 404 Firecrest front, Zipp disc rear. I don’t have a feel for how that number stacks up. I presume it’s a fair number with lots of room for improvement?
Irrespective of what BBS says, there is *always *room for improvement. Whether there is a *lot *of room isn’t really possible to answer without much more detail specific to yourself.
Time-trial ready. I had my Zipp tires at 90 psi - maybe a bit too high. No bottles.
Decent fitting off the shelf Pactimo short sleeve Ascent 3.0 skinsuit and lycra shoe covers.
Final fit used for TT. Comfortable.
I think if I were to do another TT, I’d bring my forearms closer together just for the race and widen them back to their current position for training.
I would not be surprised at such a number if I were testing your aero. Then again the range of CdA that would not surprise me is fairly broad.
You do however have opportunity to gain speed. Best of luck with it.