Hi there, im just wanting to know what do the numbers mean when your looking at a set of tires. For example: P295/50R15 i know what the last number means, but the other letters and numbers got my head spinning.
The 295 number refers to the width in milimeters (mm). Cant remember if its the cross-section or the tread, but you get the picture.
The 50 reflects a percentage ratio of the sidewall height to that width. So those tires would be 295 mm wide, the sidewalls would be 50% of that (154.5mm) and the r15 of course is a 15" diameter wheel.
The bigger the first number, the wider the wheel, the bigger the 2nd number, the "higher" the sidewalls in proportion to the width (think not lo-profile) the bigger the 3rd number, the bigger the wheel that the tire fits.
The 295 number refers to the width in milimeters (mm). Cant remember if its the cross-section or the tread, but you get the picture.
The 50 reflects a percentage ratio of the sidewall height to that width. So those tires would be 295 mm wide, the sidewalls would be 50% of that (154.5mm) and the r15 of course is a 15" diameter wheel.
The bigger the first number, the wider the wheel, the bigger the 2nd number, the "higher" the sidewalls in proportion to the width (think not lo-profile) the bigger the 3rd number, the bigger the wheel that the tire fits.
Trying to make it as simple as possible although those above have it correct.
The first number is the width, the bigger the number the wider the width, in milimeters. A 295 will be much wider than a 225.
The second number is the height. The higher the number, the taller the tire will be. Yes, this is a percentage of the width. A 70 series tire will be much taller overall than a 50 series tire. The 30 and 40 series are more the rubberband type.
As you already know, the last number is the diameter of the rim that it fits.
Yes, the "P" stands for passenger car while the "R" means it's of radial construction. You could also have another letter which indicates it's speed rating. "Z" is the highest speed rating you can have and it goes down from there. This letter is of the least significance when it comes to our cats though. It's geared more to the high end exotics that are capable of 140mph +.
Isn't speed rating for say "s' or "z" qualified at 1 hour of that sustained speed?
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
Mercury Cougar Owners
586.3K posts
20.8K members
Since 2001
A forum community dedicated to Mercury Cougar owners and enthusiasts. Come join the discussion about restoration, performance, modifications, classifieds, troubleshooting, maintenance, and more!