A super-unscientific example for how much power you could lose by having a dirty drivetrain, slow rolling tires, and bad aerodynamics

Equipment
1

Both done in the drops at relative steady state. Wind conditions were actually worse on the second example. Exact same power meter with exact same offset value.

Old bike (Niner BSB) with gravel wheels, 32c slick tires, a dirty drivetrain, and bottom bracket with old bearings

14%20PM
14%20PM1230×646 51.7 KB

New bike (Tarmac SL6) with Roval CL50, 26c tires, clean drivetrain

33%20PM
33%20PM1204×646 55.9 KB

I was surprised that the difference was so large.

2

I would have expected a bigger difference.
Interesting.
Thanks for sharing.

3

Bigger than 60 watts?? I was expecting more like 25.

4

Oh I didn’t see the power avg, I only looked at the time. I see. That is big with time + power considered.
Considered doing some Chung method testing?

5

I don’t have the old bike anymore, otherwise I totally would have tried it.