[SecondWind]

This is an addition to my earlier post showing the effect of taller tires on highway mileage. The car is a 2011 Honda CR-Z 6MT. The tires tested are the OE Dunlop 195/55R16 vs Michelin 205/65R16.

To determine the effect of the larger tires on city driving, a loop was laid out in and around Delaware, Ohio. The loop consists of 25, 35, 45 and 50 mph zones, and both stop signs and traffic lights. The loop also includes pulling into and out of some businesses. The idea is to duplicate running a series of errands.

The conclusions are that the larger tires do not affect city driving mileage. I expected, based on the opinion of others, that the larger, heavier tires would result in lower city driving mileage. I found that if I drove slower (due to traffic, etc.), that my mileage went down. I think that must be the result of more time spent in lower gears. I also found it difficult to drive consistantly. My data is not grouped together nearly as tightly as I would have liked. I think the point here is that in-town driving is strongly influenced by driving style. Highway driving is influenced much less by driving style; just a matter of setting the cruise...

The loop was run 5 times with the OEM Dunlop tires, 5 times with the Michelins, and 5 times again with Dunlops. As measured by ScanGuage II, the loop is 13.0 miles. By Google Maps, it's 12.9 miles, but Google doesn't recognize driving into a shopping center.

I drove in “normal” mode, and also as normally as possible. I do not use P&G, EOC, or any other hypermiling techniques. I shift at about 2,500 1st to 2nd; and at 2,000 or less up through 3, 4, 5, and 6. I use the brakes lightly, since it re-charges the battery, and
try to anticipte the traffic lights when possible. I decelerate in gear, again to re-charge the battery.


Run Time MPG Gallons Max RPM Max MPH
1 36.23 42.0 0.31 2,830 51
2 35.93 45.3 0.28 2,702 50
3 38.84 43.5 0.30 2,794 51
4 34.48 44.0 0.34 2,853 50
5 35.55 44.3 0.31 2,785 50
6 37.93 46.3 0.29 2,537 52
7 35.38 48.6 0.27 2,395 50
8 41.07 45.2 0.30 2,405 53
9 36.54 45.6 0.29 2,608 54
10 36.57 49.3 0.27 2,187 51
11 36.84 45.6 0.29 2,658 50
12 39.52 45.5 0.29 2,253 50
13 37.85 46.4 0.28 2,519 50
14 38.72 44.1 0.29 2,233 50
15 37.42 44.9 0.29 2,576 57