Speed crown: tt vs tri bike?

Triathlon Forum
1

I think we know which is faster in the tt vs tri bike on a truly flat race (all else the same aside from frame), and that wind will alter things (giving favour to high vs low yaw optimized frames).

But how much do the uci rules hurt the tt bikes? And with the uci relaxing the 3:1 rule, why are there not a flood of deep frames in the tt world? Kamm tail is slower than an airfoil (yeah yeah, weight and stiffness).

2

The UCI may have relaxed the 3:1 rule, but they didn’t eliminate the maximum 80mm or minimum 25mm dimension rules on the main tubes, so we’re still left with a 3.2:1 rule, at least for the main triangle…

3

The UCI may have relaxed the 3:1 rule, but they didn’t eliminate the maximum 80mm or minimum 25mm dimension rules on the main tubes, so we’re still left with a 3.2:1 rule, at least for the main triangle…

I assume saddle position is unchanged also.

4

https://m.youtube.com/watch?v=7lK1xC0Z5FA

No tri bike here, but i was a bit shocked at how close and optimized road bike with aero bars was vs the tt bike. Thinking the tri bike is not much better. Now, at yaw the difference would be larger but i am not sure if they did weighted averages for yaw.

5

Manufacturers make really, really good bikes under restrictions at this point. Even the bike companies that have started making bikes specific for tri really just end up with similar cda, just with more storage/hydration/etc at those numbers.

Aerocoach put up some of the highly regarded “illegal” frames (zipp 2001, Lotus 110) vs a P5 it just shows… we make fast bikes now.

6

same rider, same position, same frame essentially… only difference is the drop bars

https://m.youtube.com/watch?v=7lK1xC0Z5FA

No tri bike here, but i was a bit shocked at how close and optimized road bike with aero bars was vs the tt bike. Thinking the tri bike is not much better. Now, at yaw the difference would be larger but i am not sure if they did weighted averages for yaw.

7

The Cervelo P5 is UCI legal. That is a pretty fast bike by any standard.

8

The Cervelo P5 is UCI legal. That is a pretty fast bike by any standard.

So true.

The swissside talk described 8w from wheels, 8w from frame, and 10w for other stuff on the bike (i presume bars, derailiers, etc). Their data was at 30-35km/hr (this is by memory). It is a reminder that a fast frame is not that huge of a change once position is set.