Originally Posted by
GhostRider62
It is not hard to measure a difference of 5-10 watts.
An average recreational cyclist moving at 17 mph could see an increase to 17.5 with small changes in tires with same power input. Large improvements could see upwards of 1 mph improvement.
What is often erroneously assumed is the Crr published on various websites represents the actual Crr experienced on the road. Real world Crr is much, much higher and the incremental improvements are not trivial.
it is actually incredibly hard to measure a difference of 5-10 watts when you are outside in the elements. Even the slightest of breeze will swamp that kind of difference out. It's not even a constant 5-10W either. It varies with both speed and how rough the road surface is. There are plenty of roads where a wider tyre with a much higher lab test rr result would actually be faster in the real world. All that road buzz you feel through your bars is lost power. Anyway the OP was talking about lab test differences of only 2-3W, which is basically next to nothing.