Wow, as an Engineer, I never considered that, I'd think gear selection would be prime factor.
I think a changing gears would cause a significant delay.
I'm guesing your instability is due to Cadence? I know mine would be. I know folks who have hit 200+ (Honest - semi-pro) and in TT's I've been in I often see Fixed gears. They seem not worried to get a good run from a standing start, but I've never heard them speak of time to XX. Course all that matters is TT Lap/total time. . Also, Sprinters Never change gears once they start final sprint, but they are moving. But going from 30mph to 35/38 would not be as significant.

Good question Will. I use a 53/18 fixed, I'll give it a try.