Tire size reduction for winter tires
Asked by Robert Jan 17, 2018 at 11:05 AM about the 2008 Subaru Impreza 2.5i
Question type: Maintenance & Repair
The recommended tire size for a 2008 Subaru Impreza 2.5i is 205-55-16. I have
heard that a smaller tire size will provide better traction for snow tires. I know
the change will impact the spedo and odometer. My questin is will a reduction
to a 195-55-16 tire size negatively impact or damage the differential,
transmission, drivetrain?
5 Answers
Thanks tennisshoes, I keep getting mixed info on this. Even from different dealer service departments. Any chance you can tell me why this is? Im trying to go the extra mile in understanding before I fry a differential.
Thanks shoes, I appreciate the info. that definitely adds clarity. One other concern mentioned to me by one dealer I spoke with was the decrease in Circumfrence. They noted Subaru does not recommend a change of more than 1" in circumfrence. Any thoughts on the difference of circ. on the diff? The differences of the tires are listed below: 205/55-16 195/55-16 Difference Diameter inches (mm) 24.88 (631.9) 24.44 (62 -0.43 (-11) -1.7% Width inches (mm) 8.07 (205) 7.68 (195) -0.39 (-10) -4.9% Circum. inches (mm) 78.16 (1985.17) 76.8 (1950.61) -1.36 (-34.56) -1.7% Sidewall Height inches (mm) 4.44 (112.75) 4.22 (107.25) -0.22 (-5.5) -4.9% Revolutions per mile (km) 810.68 (503.73) 825.04 (512.66) 14.36 (8.92) 1.8% For the life of me I can't imagine why such little variances in dimensions, especially if all 4 tires are the same, would impact the drive train. But, I am no engineer and know the subie AWD system is very sensitive. thanks
Thanks Tom, is that related to just the circum. or is that all the dimensions listed? And, how do you know this? Just curious as I have spoken to many and wonder about validity?
Smaller tires would reduce your ground clearance a bit which is not a good idea in deep snow.