Posted by SirWeazel on February 17, 1998 at 20:35:22:
In Reply to: How to match a tire to a wheel/rim - HELP posted by David Goodrich on February 17, 1998 at 18:57:14:
215/75/14 means that your tire is 215mm (21.5 cm) wide. The 75 is the profile, or 75% of
the width (.75x215). 14, as you guessed, is the wheel diameter. a 14x7 wheel is 14" in
diameter, and 7" wide. you can calculate the overall diameter of the tire by the equation:
(2(width/10)(Profile/100))/2.54+diameter so, for your tire, it would be
(2(215/10)(75/100))/2.54+14 = 26.70 inches. You should find a new tire/wheel combo
which is close to this diameter. plus or minus 3% for cars, or 15% for trucks. If you
don't want to change your truck's performance, keep as close as possible to the original
size. if you want better handling, get a larger wheel, and lower profile tire. If you
want better off-road performance, you should get larger tires, and possibly larger rims.
15" is pretty standard for truck rims, and you should find plenty of options in that size.
just note that the equation above is a general size. Different brands/types of tires vary.
you should check with the tire dealer for specific application sizes.