Don't panic if you
don't know what all of this means, we're here to help!
The "P"
indicates that the tire is a
passenger car tire. The 235 says that the tire tread is 235 millimeters in
width. The 60 means the tire's height is 60% of the tire's width. The
"R" means it's a radial tire and the 16 indicates the overall
wheel size in inches. So a P255/60R15 is wider and shorter than a
P215/75R15. Also written on the sidewall will be maximum load as well as
inflation information and speed ratings*.
(
*Performance
Tires Only ).
To allow you
to compare tire brands, there is three other ratings written on the
sidewall of the tire. The first one is likely to say "Treadware"
and then a number such as "300". The higher number is, the
longer the projected tread life is under optimal conditions. NOTE:
Driving style, road conditions, alignment, rotation, and air pressures
and heat can affect a tire's life expectancy.
For comparison
purposes, the index used by tire manufactures is a percentage grading
based on 100. 100 being average for the base tire in that manufacturers
line. For example, a treadware rating of 150 from company "X",
means that tire will wear 1-1/2 times as well as a tire from that
company with a rating of 100 when all of the driving conditions are
constant.
As another
example, B.F. GOODRICH Radial T/A HR4's have a rating of 310 and the
B.F. GOODRICH Comp T/A HR4 has a rating of 340. This means that the Comp
T/A HR4 should last 1.096 times as long as the Radial T/A HR4.
For most of us,
the actual tread-wear warranty is easier to work with. It is the amount
of miles you can expect to drive before you will have to replace that
tire when it is properly maintained. Many tires carry a 40,000 mile
warranty, which translates to an treadware rating of approximately 360.
Another way to compare this rating is to take the number, in this
example "300", and multiply it by 2 and add 2 zeros. the
number would turn into 60,000. Which can be figured to be the
approximate life of the tire.
The second rating
is written as "Traction". This is a rating of either A, B or C
with A representing the best grade a tire can receive for it's traction
abilities. A mud and snow tire or an all season tire will almost always
have an A rating. A highway or high-speed tread could have a B or a C
rating.
The third rating
will be written as "Temperature". This rating represents the
tire's ability to stand up to high temperatures. An "A" rating
is the highest grade and "C" is the worst.
*Speed Ratings are
designated on Performance tires to indicate
the top speed for which a tire is certified. It does not indicate the
total performance capability of a tire.
(Speed Ratings Chart)
When you
are shopping for tires the first thing you need to do is determine the
size of the tire you need. This information is on the sidewall of the
tire you are going to replace. The tire size will be written as
P235/60R16.