Wheels: Smaller rims, taller sidewalls?

[Vekke]

Based on my own road during one day testing. Which has bee best setup with 215/55r18 tires on my test route was 16,0kWh average. Then outside temp was 17,0 celsius around 5,15 in the morning.

Changed the 155/70R19 under and went back to road to test at 6,00
No wind temp has risen to 18 celsius. Did two runs to heat the tires and car back up. on second run temp was 19,0 celsius. Got 15,35 kWh average.

Thats 4,0% difference. 1 celsius difference has been 0,12kWh in cloudy weather. So temp corrected result 2,6%

That was with too wide tire deflectors. Narrowed them down in front and back about 60mm to match tires. 8,38 went again to test. and got 14,8kWh still no wind then outside temp23,5c.

The 215/55r18 setup at 23,0c was average 15,3 kWh on other day results no wind. That is 3,2% difference.

The 155 have 0,84% bigger diameter, that was not taken into account in the tests. So I would say they are 4% better for energy consumption in this car and setup.

[cRiPpLe_rOoStEr]

Most people here may not know it, but the latest models of the 2nd generation of the Renault Clio which had an extended production run in Argentina had 13" rims instead of the 14" which were the standard when it was launched. Sidewalls didn't seem so taller than the ones of the early Clio II my father used to own for a while, yet I don't know if the differential ratio had been tweaked on those later models in order to compensate for smaller tires.