Tires are the only part of your vehicle that touches the road, so they affect braking, handling, comfort and fuel economy more than almost any other part. This guide explains how to read the numbers on a tire, how to choose a type for how you drive and when it is time to replace them.
How to read a tire size
A size such as 225/65R17 102H contains five pieces of information. 225 is the tire width in millimeters. 65 is the aspect ratio: the sidewall height as a percentage of the width. R means radial construction. 17 is the wheel diameter in inches. 102H is the load index and speed rating. Your vehicle's correct size is on the placard in the driver's door jamb and in the owner's manual. Always match the size, load index and speed rating at least to the original specification.
Choose the type for how you drive
- All-season: a balanced choice for daily driving in mild climates, with light snow capability.
- Summer or performance: better grip and handling on dry and wet roads in warm weather, but they harden and lose grip in the cold and are not for snow.
- Winter: a softer rubber compound and deep sipes grip in temperatures below about 45 degrees Fahrenheit and on snow and ice.
- All-terrain: a tougher tread for trucks and SUVs that spend time on gravel and trails as well as on the road, with a little more noise.
- Mud-terrain: an aggressive tread for serious off-road use, loud and slower to wear on pavement.
Check the numbers that matter
Look at the treadwear, traction and temperature grades (UTQG) printed on the sidewall as a rough comparison, the load rating for trucks and anything you tow, and the date code. The date code is four digits: the first two are the week and the last two are the year, so 2823 means the 28th week of 2023. Tires age even when they are not used, and many makers advise replacing them after six to ten years.
When to replace tires
Replace tires when the tread is worn to 2/32 of an inch, which is where the wear bars become flush with the tread. A quick check is the penny test: put a coin in the groove with the head upside down, and if you can see all of the head, the tread is too low. Also replace tires with bulges, cracks, or a puncture in the sidewall.
Common questions
Should I replace all four tires at once?
It is best to replace them in sets of four, or at least in pairs on the same axle with the same type, because mixing tires changes grip and stability. On an all-wheel-drive vehicle, large differences in tread depth can also strain the drivetrain.
Can I change the tire size?
Small changes are possible, but the overall diameter should stay within about three percent of the original so the speedometer and the vehicle systems stay accurate. A larger tire also needs clearance.
Do I need a TPMS sensor?
Most modern vehicles have a tire pressure monitoring system. Sensors are separate from tires and can be moved or replaced when you change tires.
Where to buy
We carry wheel studs, lug nuts, spacers and fitment parts in wheels and tires, and suspension parts that affect how tires wear in suspension and components. We are an authorized dealer for every brand we sell, shipping is free anywhere in the USA, and returns are accepted within 60 days (unused, in the original packaging) and return shipping is free. Not sure what fits your vehicle? Contact our support team and we will help you check before you order.