[womprat]

I think it depends on the tyre. Tyres design for low RR will probably not gain from extra pressure.

I get an unscientific 6% with 32psi -> 40 psi (41 max sidewall) with Bridgestone sport tourers. These tires are grippy, and perhaps sacrifice rolling resistance for performance, so respond well to more pressure?

The 6% seems to be consistent average any way I do the numbers accross all tanks since I made the change to high pressure. I have a pretty consistent commute, and exclude tanks that include long road trips or highway driving. I ran the manurfacturers pressure for about 10 tanks first. I do lots of low speed coast downs where RR is going to be a big factor.

I find running higher pressure improves steering response and feel - which I prefer. I hate cars that don't feel like the steering is connected to anything, and positioning the car on the road is guesswork - pumping up the pressure will improve your fine control of the car and possibly save your bacon if you have to take evasive action. It's a bit harsh on rough surface and scary on gravel/dirt. :S