Czarvtte

Purchased some 10.5 x 18 rear wheels for my 88 and I'm undecided on 295/30/18 or 295/35/18 tires. What size are you guys running on your 10.5 x 18 rear wheels? I'm thinking that the 295/30's will make car sit lower in the back...correct? Thx for the help!

Btw...I'm running 9.5 x 17 up front with 275/40's.

bogus

The 295/30/18 will result in an overall height of 25"

The 275/40/17 is 25.6"

And the 295/35/18 is 26".

Czarvtte

Thanks. I'm thinking that the rear height should be higher than the front so the 295/35/18 would be the best fitment?

SeanHM

You want at least as much overall diameter as the front and if it doesn't have the same or more sidewall height it will look funny. To achieve that with 17's I have 275/40's in front and 315/35's in the rear. Not sure but you should have room for the 315's depending on the wheel. Bear in mind, same size tire from different manufacturers will vary somewhat in their actual dimensions.

Czarvtte

Thanks!

DanielRicany

Your speedometer will be inaccurate if you change the total diameter from the stock size.

maddogwyatt

Yeah, good point. You can work out the diameter of wheel including tyre if you know the height of the tyre sidewall. This is shown as a percentage of the width 295/35/18. So sidewall will be 35% of 295mm = 103.25mm or 4in 1/16th. Add that to the rim diameter (18inches), and you have it - 22in 1/16th. Multiply that by PI (22/7), and you'll have the circumference a shade over 71 inches. Compare that with your original wheels, and you'll see how much your speedo will be out. I learned all this when my brother was building a trike and needed to to sort out wheels, tyres and differential ratios Now I've written this, I'm not so confident. Please correct me if I'm wrong