Tire size question
- Thread starter Santeeford
- Start date
Whytry91
New Member
04sleeper
Founding Member
DucatiRdr
New Member
What about speedo error for the difference in tire circumference? My 88 has 225/60-15 with a circumference of 153.54". A 225/50-16 has a circumference of 143.53 for a difference of 6.5%. Is there a new speedo drive gear to account for the change in circumference?
WHy do you want to decrease tire diameter?
If you want wider rubber for your car, you can use a 245/55/15. This will keep your diameter the same and not require a gear change.
For the original poster, a 245/50/16 will also keep factory tire diamter and not require a speedo change
FWIW, its not the EXACT factory diameter, but its pretty damn close. B/t the 225/60/15 and 245/50/16 There's a .79" difference in overall height, leading to a .05" difference in circumference. At 60MPH, your speedo will be ~2MPH off.
Remember, when changing wheel size or tire width, the middle number of the three is the sidewall height as a percentage of the overall tire width. So as the width (first number) goes up, the sidewall percentage (second number) must go down to keep the overall dimension the same. The same is true when going to larger rims w/ the same width tire. The sidewall percentage must go down to accommodate the larger wheel.
225/60/15 ~= 245/50/16 ~= 245/45/17 ~= 245/40/18 and so on
so if you're sticking w/ a 15" wheel keep in mind that the sidewall must be tall enough to make the stock 15x7 wheel width. A 60 on a 225 is plenty. You can go to a 245/55/15 which are rare as crap, but its the exact same overall size.
Remember, when changing wheel size or tire width, the middle number of the three is the sidewall height as a percentage of the overall tire width. So as the width (first number) goes up, the sidewall percentage (second number) must go down to keep the overall dimension the same. The same is true when going to larger rims w/ the same width tire. The sidewall percentage must go down to accommodate the larger wheel.
225/60/15 ~= 245/50/16 ~= 245/45/17 ~= 245/40/18 and so on
so if you're sticking w/ a 15" wheel keep in mind that the sidewall must be tall enough to make the stock 15x7 wheel width. A 60 on a 225 is plenty. You can go to a 245/55/15 which are rare as crap, but its the exact same overall size.
DucatiRdr
New Member
For my '88 I wasn't looking to change overall wheel height, just tire width. I am going to pick up a set of 16" pony wheels and wanted to bump up the width from the OEM 225 to something a bit more asthetically pleasing. Remember, my '88 has the "old style" fenders/fender liners. I would like to avoid tire-fender contact and don't want to have to roll the fenders. Will a 245/50 16 fit the rear? Do I need to reverse the quads?
On my '88 i went from 10-holes to 16" pony wheels with 245/50/16 tires. The rear fit fine, the front had a little rub at full lock. Nothing major.
I know have 245/45/17" tires on it
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