Celica Forums General Discussion Exterior tire size

i know that this one is probably a repost but i really need everbodys help what is the better size of tires i could put on the 18"? is it the 215/35/18 or 225/40/18?

given the overall diameter of the stock 15" is 23.7945 and 16" is 23.995 you would be able to go with a 215/35/18 without screwing up your gauges to much the overall diameter of the 215/35/18 is 23.8695 if you went with the 225/40/18 you would totally blow it out 25.02 is overall diameter..you might rub at that point. When I first bought my car someone had put on 225/50/16 on the car and they rub every time I reached the end of my turning radius. My overall diamter at that point was 24.775 almost an inch to big.

oh by the way, they way i figured it out was using this calculation

just imput your specific numbers and presto you got overall diameter

To find the Overall Diameter and Section Width of a 175/70R15 tire do the following:

1. Multiply 175 by .039 to convert the Section Width from millimeters to inches. 175 x .039 = 6.8".

2. You will need to find the Section Height to determine the Overall Diameter so multiply the Section Width by the Aspect Ratio.
6.8 x .70 = 4.8".

3. To find the Overall Diameter you need to twice add the Section Height and then add this sum to the Rim Diameter.
4.76 + 4.76 +15 = 24.5"