Size of weels
Tire sizes are generally standard, however there are slight differences between brands. What is of primary concern is the rolling diameter of each tire. The numbers which you are tlaking about relate to "aspect ratio" (how wide a tire is in relation to its diameter) differing aspect ratios generally affect how wide the tire is. The numbers on the door sticker are correct, but it is generally better to have different #'s front to rear only on one axle. I would actually use the 70's on the rear, as they have a slightly larger "footprint" All told, the difference between your front and rear tires is so insignifigant, that it is almost laughable that anyone would even bother you about it! About the only place I know of that people are that uninformed and crazy is in California!!!
To check rolling circumference, park on a long flat place like a parking lot. Make a mark with crayon on the tire and on the ground as a starting reference. Roll the car 'till the mark on the tire is exactly down, where it began. Mark the ground at this point and measure the distance between both marks. Compare this both front and back. This difference is especially important with 4X4's where a difference can cause the transfer case to wrap up internally and fail. On a 2wd vehicle the difference means nearly nothing mechanically. As far as how wide a tire is, it only becomes critical when the tire is so wide that it interferes with the wheel well or rear suspension. Good luck with your crazy inspector!
Oct 07, 2008 |
1994 Pontiac Sunbird