Gas Mileage

[richamer1]

I have a 99 s-10 2.2 Automatic and I am getting about 21 or 22 MPG. This seems low. I did go from 215/75/14 to 235/75/15 tires which the new tires are about 2 inches taller. I did not think the tires could make that much difference. I thought that I used to get around 24 to 26 MPG. What kind of mileage do you guys get ? Thank You

[blazerbob91]

Here is a link to calculate the effect of different size tires. The larger tires you have are affecting your recorded gas milage.

http://www.miata.net/garage/tirecalc.html

I recently replaced my 205/75/15 tiger paws with a Winterizer 215/65/15 tires. I thought I would get better milage with them but I got th opposite. I lost 1.5mpg. I think it's due to the snow tire type tread.

The web site showed me the with the new tires my speedo is showing 4.1% faster than I'm really going.

[old_master]

The VSS, (Vehicle Speed Sensor) measures PPM, (Pulses Per Mile). If the circumference of the new tire is larger, the VSS will sense less pulses per mile. The speedometer will indicate a slower speed and odometer will indicate less miles travelled giving you a lower MPG figure. If the circumference is 10% larger, expect a 10% decrease in speedometer, odometer and fuel mileage calculations. Actual fuel mileage will not change significantly just by changing tires.