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Companies with a fleet of vehicles (taxi, limo, etc) think of car tires as a cost that cut into their profits.

For this reason, it's best for them to buy the cheapest tire for the same expected mileage lifespan. However some tires will wear faster so we cannot simply compare the price.

How would a company decide which tire to buy?

Is there a simple metric to compare tire lifespan (Treadwear cost per mile) ? How do they choose the best tire for the price given they don't care about drive comfort but want to instead maximize for mileage?

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  • Consider safety V price ? And tyre cost per mile or kilometer has been used for years especially in the trucking industry...
    – Solar Mike
    Dec 6 '17 at 20:20
  • I bought one of these tread gauges recently and am going to start measuring my tread wear over time. Would be good if there was a public dataset available that folks could contribute to.
    – jxramos
    Dec 6 '17 at 22:57
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The cheapest tire isn't always going to be the cheapest per mile. A company with a large fleet like a taxi operation has the advantage of being able to try many different options to see what might end up being the cheapest overall choice. To get started in the right direction, in the US anyway, there is a tire grading system.

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Picture from this site. Not sure what they do, but they had a nice picture and a write up on UTQG.

The UTQG/Uniform Tire Quality Grading system was put into place to solve the issue you speak of. Tire companies could advertise milage warranties and traction levels, but it was difficult to get a clear picture of how one tires wear compared to another.

This system gives tires a rating number (and some letters) to indicate how long the tire is expected to live. The picture of the tire above has a treadwear rating of 400. You could compare that to a terrible tire with a rating of 100, and be reasonably sure that it should last about 4 times as long (100 * 4 = 400). The AA is the traction rating, and important for choosing a tire, but not as important for how long it will last. With some casual tire shopping, I have seen ratings in the 300-700 range.

The treadwear rating isn't perfect, and there are accusations of manufactures trying to "game" the system like they do with car fuel economy ratings. A tire with a 600 rating might not last exactly twice as long as a 300 tire, but it should be a much longer lasting tire. Again, the fleet testing will help find the real winners for a specific application.

Another thing to consider on tires is something called "low rolling resistance". Special compounds and tread patterns are used to make the tire roll easier. This is supposed to save fuel, and make up for the slightly higher price of the tire. These tires are marketed as being "green" or "eco" because less fuel saves the environment.

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    One thing I don't see you mentioning here about the UTQG, that being any given rating is only valid against other tires from the same manufacturer. A 700 rating from Michelin may not give you the same as a 700 from Sumitomo.
    – Pᴀᴜʟsᴛᴇʀ2 ♦
    Dec 6 '17 at 23:00
  • @Pᴀᴜʟsᴛᴇʀ2 Honestly I don't know where you get that. There are "standard" tires with a treadwear rating of 100 called CMT (course monitoring tires) which are provided by NHTSA. All manufaturer claims are based on testing relative to these "standard test" tires. I think they run them somewhere down south (Texas?) and derive the treadwear rating from there. Certainly not an exact science, but still apples-apples testing in my [never] humble opinion.
    – SteveRacer
    Dec 7 '17 at 7:06
  • @SteveRacer - Read the second paragraph under Treadwear Grades in this Tire Rack page. This isn't the only place I've seen this information.
    – Pᴀᴜʟsᴛᴇʀ2 ♦
    Dec 7 '17 at 13:43
  • I think a good summary would be that they should compare results to a standard tire, but the manufacturer is the one doing the test, with no active supervision. Manufacturers can also put lower ratings than they should to help differentiate different models of tires.
    – JPhi1618
    Dec 7 '17 at 13:47
  • Tire Rack piece makes it seem like the Treadwear rating isn't necessarily "valid" at all. I suppose it's a rather nebulous number anyway, as it's only relative to a CMT "testing" reference with no inherent knowledge of how that carcass lasts. The only take-away that's useful is that the Monster Piloto Extemo Summer Performance with a UTQG treadwear of "50" is going to burn rather quickly [and fun-ly]., where the Harold's Honest Holeproof Hypermiler with a treadwear rating of "600" might last a very long time. Unfortunately. Well, I learned something from this: you can't trust anything!
    – SteveRacer
    Dec 8 '17 at 2:35
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I don't know the results of how any of the specific tires performed or some of the specific details for how they chose the tests but Consumer Reports has this treadwear course they carry out these tire tests with. Apparently they put several tires to the test over a predetermined route and measure treadwear over the mileage they cover and actually accumulate a tread thickness vs mileage profile. You might consider paying up and checking out their report to see what findings they found. Check out the video here: 1,000 Miles a Day: Consumer Reports Tire Testing | Consumer Reports.

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