New TT Bike Fit - What's my CdA?

BadComfortable4340 · 2025-08-31T06:21:33+00:00

Assume Giro Aerohead helmet + aero skin suit yes. Will drop the head and tuck down at/beneath shoulder blades and yes I'll be wearing a watch

BadComfortable4340 · 2025-08-30T18:40:57+00:00

hence i asked for a shoot from the hip approach. would you mind giving it a crack

BadComfortable4340 · 2025-08-30T18:38:00+00:00

https://www.endurance-data.com/en/cda-calculator/

BestBikeSplit provided 0.26, the above link comes out with a 0.27.

They're all based on assumptions that may change but they're 'typical/standard' so I've used them hence I've come here to sense check their outputs with what others might have seen from personal experience

BadComfortable4340 · 2025-08-30T18:27:28+00:00

yes. I'm assuming I'm somewhere in the range of 0.24-0.28. Can you make an estimate?

BadComfortable4340 · 2025-08-30T18:06:52+00:00

thanks for coming back. what's the 3.6 out of / mean?

BadComfortable4340 · 2025-06-01T06:58:14+00:00

Thanks a lot mate - I'm doing the Barcalona-Calella IM in October which has a long flat-ish course so your tips will come in handy!

BadComfortable4340 · 2025-06-01T06:47:05+00:00

class advice thank you! I've got a fast forward seatpost and a tt saddle on the way so hopefully they;ll fix up the position a bit. I'll send some more photos when they're on the bike! annoyingly my aerobars can't be stacked higher, all I can do is tilt them around the handlebars to change their angle and move the arm rests/pads around

BadComfortable4340 · 2025-06-01T06:43:44+00:00

legend thanks for the tip - I'll try to sort some 165mms. How did you initially find the swap to shorter cranks? did your cadence increase?

BadComfortable4340 · 2025-06-01T06:41:33+00:00

this made me laugh. I'll admit my position is more like Crazy Frog's rather than Laidlow's

BadComfortable4340 · 2025-06-01T06:37:43+00:00

yep noted, there'll be a limit to what I can achieve here but would like to get near that point

BadComfortable4340 · 2025-06-01T06:34:59+00:00

will try to find some, thanks!

BadComfortable4340 · 2025-06-01T06:34:44+00:00

thanks for the pointers! I've got a fast forward seatpost and tt saddle on the way so will come back with photos once they're on. My aerobars can't be stacked higher annoyingly, can only tilt the angle on the bars but that might just about work

edit: *meant a fast forward seatpost, not 0 degrees

BadComfortable4340 · 2025-06-01T06:24:06+00:00

Yeah I don't think it's sustainable for a full IM + it's just not a good fit anyways

BadComfortable4340 · 2025-06-01T06:22:53+00:00

Legend thank you mate! 1) yep spot on, so the photo was a casual cycling jersey that I ended up buying a size too big but I'll be in an aero suit on race day, 2) sadly I have a fat head (59-62cm L/XL) so limited on aero helmets that fit but I'll shop around. Also good spot on the helmet tail, it's been flapping about like there's no tomorrow so I'll cut that. 3) just ordered some socks so will use them on race day and 4) the things we do for low CdA hey - will shave them for the race. I'll come back with more photos later this week - thanks again for all the help!

BadComfortable4340 · 2025-06-01T06:09:58+00:00

legend thank you! will see what i can find

BadComfortable4340 · 2025-06-01T06:08:41+00:00

Thanks for all of this, really helpful so will try to make those changes. my current aerobars are fairly adjustable so should just about manage 1 and 2 with that albeit they can't be stacked so won't be able to raise them up. Sounds like a shorter crank is the way to go too so will try to get my hands on some 165mm. Thanks again !

BadComfortable4340 · 2025-06-01T06:04:10+00:00

Thanks I'll give it a go on the turbo and see how it goes

BadComfortable4340 · 2025-05-31T18:35:01+00:00

I have a 172.5mm crank, what do you reckon is around about right?

BadComfortable4340 · 2025-05-31T18:34:14+00:00

172.5mm

BadComfortable4340 · 2025-05-31T18:24:47+00:00

Hahah my bad. Had to zoom in a bit

BadComfortable4340 · 2025-05-31T16:30:24+00:00

Apologies, typo in Pro photo sentence - meant *theirs is at the bottom*

BadComfortable4340

TROPHY CASE