bojangles

Is there a noticable difference in the width of a R70 series vs a R75 series tire? I would like to replace my 6.70 x 15's with a 205 x R75 X 15. I seen on Coker's site they have only 205 xR70 x15's.
Any recommendations?
Thanks

decarmine

The width of an R70 and an R75 should be the same -- in this case 205 millimeters -- about 8 inches. The difference will be in the height. The sidewall of a 70-series tire will be 70% of the width, a 75 series will be 75% of the width. If you want the same HEIGHT in a 70 series, then you need to go wider in the width -- about 219. Of course, they don't make 219...

a 215 will be a little wider and a little shorter, while a 225 will be even wider, and a little taller.

Frank

66since71

205 is the mounted width (in mm) of the tire on a particular rim width (probably 6" for a 205)
R is for Radial
70 (or 75) is the ratio of the width to the sidewall height.
15 is the rim diameter

So a 75 will be a taller tire, and closer to the height of the 6.70x15.

If you go 70 then a 215 will get you closer to correct height

I see Frank (decarmine) answered at the same time I did!!

bojangles

thanks for the information.. Will 215's fit on a '63 Vette?

Lee H

205 70 15 = 8.1" wide 5.7" tall Side wall 26.3" height
205 75 15 = 8.1" wide 6.1" tall Side wall 27.1" height
215 70 15 = 8.5" wide 5.9" tall Side wall 26.9" height
225 70 15 = 8.9" wide 6.2" tall Side wall 27.4" height

These are generic calculations as all tire manufactures are different.

vetzs

Of further interest to you is the spare if you elect to carry one. If the size does not match what's on the ground if you get a flat on the rear you should rotate a front to the rear installing the spare (odd size) on the front. This is only important if you have posi.

I have 215/70's all around mounted on 15x6 knockoffs. The tire fits in my spare tire tub using the longer hanger bolts. This gives a slight exposure of the spare to the elements.

JohnZ

The Diamond Back 205/75-15 Firestone Supreme Si tire has about a 1-1/4" wider tread than the Coker 205/75-15, and doesn't look "skinny" like the Coker and the original 7.75-15's do; no rubbing under any conditions, no problems, they balance, and they're round.

watson

I also have 215/70's all around with no problems. I would caution you to check the archives for a lot of material on Coker tires. In short, most folks think that they are junk compared to the Diamondback. I have had both, and I would not take another set of Cokers if they were free. The Diamondbacks that I have now are great.

Doc