momo15

Let's be honest, how much time can a new TT frame (Shiv, etc.) save a casual TT rider over an entry level TT bike (Felt S22/32, Cervelo P2, Motobecane)? Currently, I am doing TT's with clip-ons and a dedicated saddle/seatpost. I think most of the gains that I would see with a new TT bike would be in the position, steering, and stability of a specific TT bike, but would a new super-aero frame provide any real benefit to an amateur who struggles to hold a low 20's mph over a 10 mile TT course?

I realize that the question of high-end vs entry level road bike has been done to death. I know that the motor matters most. I know that the depth of wallet is usually the ultimate judge. I just want to know if there is any special difference in this debate when it comes to a TT bike, as the aero technology weighs so much more on the overall speed of the bike in this situation.

Lexi01

No. No difference.

asgelle

https://forum.slowtwitch.com/gforum.c...rowed;#1802183
The difference between a very good and excellent frame would be on the order of 1-2 minutes in a 10 mile TT. One of the new super frames would give an even larger time benefit.

rbart4506

^^^^hahaha...sure pass me the kool-aid please

StanSeven

I just started to look at that thread and see it's 23 pages. Plus I'm not smart enough to understand most of what I saw on page 1.

The May issue of Velo tested four very high end aero road bikes and found 45 seconds difference between the best and worse over a 40K tt. I assume tt bikes will have similar differences.

rruff

Check your math. A difference in CdA of ~.03 would be on the high end of difference between a low end TT frame and the best. Like a CdA of .24 vs .27 or an overall drag reduction of >10%. That equates to ~3 sec per km or 48s for a 10 mile TT.

This is a good site to check out: https://www.cyclingpowermodels.com/Co...odynamics.aspx

asgelle

Using Tom's measured values for CdA of 0.228 for the P2K and 0.205 for the P3 in analyticcyling.com with all other values as defaults. I get time savings of 51 seconds @ 23 mph and 59 seconds @ 20 mph. So it looks like my rough guess was a little high.

Based on the OP's statement of riding in the low 20's mph, I calculated power for speed at CdA of 0.228 for 23 and 20 mph (182W, 126W). Using those powers, I calculated speed for power with a CdA of 0.205 (23.78mph, 20.67 mph) to get time savings.

asgelle

Tom brought data to the party. What have you got?