Quote:
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 data here. One thing to note though, you have a very light car. The point of diminishing returns will likely be higher on heavier vehicles, like a full size truck or a Prius with all those batteries.
If you tried running only 50psi in the tires of a semi truck, you'd probably be highly disappointed in your fuel consumption.