Skip the auto shop - Our mechanics make house calls

Understanding Tire Service Descriptions: Speed Rating and Load Index

Tire Speed and Load
Steve Lagreca / Shutterstock.com

There never seems to be a shortage of questions you are asked when you inquire about tires. What size do you need? What speed rating do you require? How will you be using them? What load index do you need?

Where do you find this information, and what does it even mean? It may seem overwhelming, but knowing a few key pieces of information will help you find the correct tire for your vehicle.

Where to find Load Index and Speed Rating on your tire

On the sidewall of your tire, your tire size is indicated in the format of 215/60R16. Immediately following the tire size is another number and a letter like 94S. This is the load index and speed rating of your tire. Let’s decipher it.

Load Index

The number is the load index. It indicates how much weight the tire can bear. The higher the load index number, the more weight it can carry:

Example Load Index Chart

As you can see, the number 94 means each tire can bear up to 1,477 lbs of weight, or 670 kg. The load index of your tires shouldn’t be reduced. A tire is matched precisely to a vehicle when it is engineered. Using a tire with a lower load index could result in undesirable tire wear or failure. You may choose to use a load index higher than your vehicle was originally equipped with, and the load capacity will increase.

Speed Rating

Beside the load index is a letter which indicates the speed rating. In our example the letter is S. As with the load index, the higher the letter in the alphabet, the higher the speed rating:

Example Speed Rating Chart

The speed rating is the maximum speed a tire can be operated up to. A tire’s speed rating is void if it has been punctured, patched, or otherwise damaged. The manufacturer can no longer guarantee the safe operation of the tire at high speed.

High Performance Speed Rating

High performance tires have a speed rating in a slightly different fashion. In the tire size, the addition of a Z indicates it is a tire capable of speeds in excess of 149 mph. It is shown as: 215/60ZR16

That was thought to be as much rating as was needed, and the Z rating encompassed all tires rated at 149 mph and higher. Since the inception of Z-rated tires, further clarification has occurred that identified specific speed ratings for above-149 mph speeds. W-rated tires indicate a tire capable of speeds up to 168 mph, and Y rated tires up to 186 mph. Anything beyond Y rated tires is shown with the load index/speed rating in parentheses. For example, it could be shown as (99Y).

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
P2422 OBD-II Trouble Code: Evaporative Emissions Control System (EVAP) Vent Valve Stuck Closed
Diagnostic Trouble Code (DTC): P2422 P2422 code definition Evaporative Emissions Control System (EVAP)...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...


Related questions

Q: Rear tire bent

An impact that can bend a rim can cause further damage which are not immediately visible. Issues with bent tires may also indicate further problems with the suspension or steering. I would have this issue looked over by a certified...

Q: Are Euro-Metric and P-Metric Tires Interchangeable?

When looking for tires, you may run into some confusion when you see words like euro-metric or p-metric. With all of the other ratings on tires, such as temperature, load, treadwear, and traction, adding these other terms into the mix...

Q: How Long is my Spare Tire Good For?

We all hope that we never need to use our spare tire. If you have never had to use your spare tire, you should consider yourself lucky. On the rare occasion that it needs to be used, the last thing...