It's been kind of warm since switching to my 195 snows
Running about 7.9L/100km (29.7mpg) vs 8.5 (27.6mpg) with my 235 summers.
I'm surprised.
Ugh, wrongChiadog wrote:Could be you are actually going less distance. If wheel diameter and aspect ratio are the same, the tire diameter of the 195 is probably about 1.5" less than the 235.
http://www.csgnetwork.com/speedocalibcalc.html
He's 100% right, but if you're using the same aspect ratio on 235s and 195s, then your diameter is way off and your MPGs would be severely inflated.thebarber wrote:Ugh, wrongChiadog wrote:Could be you are actually going less distance. If wheel diameter and aspect ratio are the same, the tire diameter of the 195 is probably about 1.5" less than the 235.
http://www.csgnetwork.com/speedocalibcalc.html
1.3% difference in speed variance does not equate to 8% better FEkumquat wrote:He's 100% right, but if you're using the same aspect ratio on 235s and 195s, then your diameter is way off and your MPGs would be severely inflated.thebarber wrote:Ugh, wrongChiadog wrote:Could be you are actually going less distance. If wheel diameter and aspect ratio are the same, the tire diameter of the 195 is probably about 1.5" less than the 235.
http://www.csgnetwork.com/speedocalibcalc.html
Still, chances are that the diameter of your summer and winter tires are different by at least a couple of percent, which could account for most or all of the variation, especially once you take into account other factors not controlled for (temperature, length of warm-up time, small variations in traffic and trips, type of driving, use of AC/defroster, rolling resistance differences, etc).
Well 1.3% difference in diameter equals a 1.3% difference in circumference and a 1.3% difference in measured speed/distance traveled and therefore a 1.3% difference in fuel economy.thebarber wrote:1.3% difference in speed variance does not equate to 8% better FEkumquat wrote:He's 100% right, but if you're using the same aspect ratio on 235s and 195s, then your diameter is way off and your MPGs would be severely inflated.thebarber wrote: Ugh, wrong
Still, chances are that the diameter of your summer and winter tires are different by at least a couple of percent, which could account for most or all of the variation, especially once you take into account other factors not controlled for (temperature, length of warm-up time, small variations in traffic and trips, type of driving, use of AC/defroster, rolling resistance differences, etc).
195-65-15 to 235-45-17
FYI, got same 8.5L/100km on 225-45-17
If you think anyone would run the same sidewall profile on a 195 to a 235, give your fucking head a shake