I'm going from 275/70 R16 to 285/75 R16. Getting 14-15mpg right now. How much do you think the mileage will drop? Estimates on speedometer discrepancies?
Changing tire size fuel mileage (1 Viewer)
- Thread starter Publius
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The difference in speedometer accuracy (assuming 100% accurate now) will be the same as the percentage difference in tire height. In your case, about 5%.
Mileage depends on the driver.
Mileage depends on the driver.
Speedometer error is also an Odometer error....
With the larger tire your odometer will read low, just as your speedometer reads low. So when you go to do the fuel economy calculation you will need to factor that out of your final MPG calculation.
-G
I changed from a 275/65R18 (32.09" dia) to 275/70R18 (33.19" dia) last time I got tires (same tire - Nitto Terra Grappler G2). I saw about a .75mpg decrease in fuel economy after correcting for the increased tire size (~14mpg average to just over ~13mpg average). My difference in size is about 3.4% on the speedo and yours can be calculated here: Tire Size Calculator - https://tiresize.com/calculator/ .
I also noticed a perceivable decrease in power/acceleration with the larger size. Enough difference that I'd consider going back to the smaller size next time around.
I also noticed a perceivable decrease in power/acceleration with the larger size. Enough difference that I'd consider going back to the smaller size next time around.
