[diamondlarry]

Originally Posted by MetroMPG

More inflation vs. rolling resistance data for the pile.

It matches the previous tests (meaning, rolling resistance decreases significantly up to a certain pressure, then plateaus).

Tire tested: Bridgestone Potenza RE92 LRR tires in 165/65R14 size (Honda Insight OEM tire, installed on Geo Metro electric car - ForkenSwift)




Weather: 25C, 8 km/h SW wind (test course ran NW/SE)

Methodology:

• tires were pumped up to 70 PSI, drove to test route (< .5 km), pressure adjusted
• car was reversed up a small hill (approx. 2 ft. elevation) and stopped at a marked point
• hand brake was used to stop - hydraulic brakes were not used at all during the test or on the short drive to the test area
• transmission in neutral, hand brake was released
• car rolled down short hill onto a flat run-out area
• where the car stopped, the road was marked
• pressure was adjusted (dropped 10 PSI)
• rinse & repeat

Results:



For kicks, see also: comparing RE92's @ 50 PSI to space saver spare tire donuts @ 70 psi - Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Poll Results

Very interesting results. Anyone have any ideas on what may be causing the distance to decrease with the higher pressures?