Originally Posted by datlas

I am no longer a GCN fanboy but I still sometimes watch their videos.

There is a recent one where Si rides a couple courses with his 10-year old bike and his current one, and in both cases he was about 3KPH faster on the newer bike.

As a retrogrouch, I like to think it's 99% the engine, and I reconcile the moderate difference in the video based on sample error, placebo effect, more aggressive (aero) body position, and possibly aero wheels.

Any thoughts?