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# Tire Treadwear - Calculate tire life

This is about using Treadware to calculate a tire's expected life span.   If you missed the overview see: Treadwear Part 1

## How long will this tire last?

Remember that the most effective use of a treadwear comparison is between two different tires made by the same manufacturer.   You may use it as a rough guide to compare tires of two different brands but the best use is the same brand.

Look for the word "TREADWEAR"  on the tire sidewall followed by a number. In the photo below the treadwear rating of the tire is 340.

The Treadwear rating is not widely used because it is considered to be unreliable because each manufacturer does their own treadwear rating.

Since a standard tire has a rating of 100,  another tire with a rating of 200 could  be expected to last twice as long as the tire with a rating of 100. It's that simple!

No serious, reputable tire expert will give you a precise answer to that question unless he knows everything about your driving habits, conditions, vehicle and it's mechanical condition, climate, terrain, etc. All these things can affect your tire's life. If someone claims otherwise, that should be a red flag for you.

### Calculations

#### Good Deals

If you like to shop on line we suggest you consider the manufacturer's promotions available from The Tire Rack's Special Offers: You may be able to save on quality tires that will suit your needs.

I'm going to walk you through some calculations to show you how easily this can help you. Don't worry if you have trouble doing these kind of calculations, I even have an on line calculator which will do all the math for you, but in order for you to feel confident about this, it is useful for you to follow along with me. OK?

When you go shopping for tires you probably already have tires on your vehicle which you know something about. This is where you start.

For example, if you have a tire which gave you 20 months of use and its treadwear rating was 240, purchasing a new tire with that same rating -- especially if it is the same brand of tire, should give you about the same life.

You can divide the life of the tire by it's treadwear number to get a factor that you can use to estimate how long a tire with a different treadwear will last. Using the example we just gave,

20 divided by 240 gives 0.083.

So, if you multiply another treadwear rate by this factor you can see that a tire with a Treadwear 100 would have an expected life of 8.3 months

100 x .083= 8.3

and if you considered a tire with Treadwear 300 you might expect that tire to last 24.9 months.

300 x .083 = 24.9

So, now you ask yourself: Will I be happy if this new tire gives me almost 25 months (or whatever you calculated using your own numbers) of service? If the answer is "Yes" keep that tire on your list, otherwise look for something different. Got the idea?

### Putting it all together

You can use the treadwear rating as one of your tools to select the best tire for you. It may not be the only one you need to consider.

Sometimes, other factors, such as traction, load, speed, handling or noise may be more important to you than just life expectation alone.

You will probably discover that if you examine high performance tires, that the treadwear rating is different from a more popular tire and the price may be higher. This is because the ingredients of the high performance tire usually cost more than those used in ordinary tires, and unfortunately they may wear out faster. If you are very demanding in your car's performance and handling, you may have to pay a higher price to get what you want.

So, if you discover that a higher priced tire has a lower Treadwear than a more economic tire, you might be looking at two totally different classes of tire. The treadwear vs price comparison can alert you to this difference.

And always be cautious in comparing one brand's treadwear with another brand. They should be similiar, but there's no regulation to ensure that they will be.