If you consider 2 tires, both the same model, type, 80K mile rated, etc, and one is a 13" tire and the other is a 17" tire. Obviously, the 13" tire will have to turn many more revolutions to travel the 80K miles than will the 17" tire (assuming the 17" tire isn't such a low profile that it's overall diameter is greater than that of the 13" tire). Is the 13" tire composed of a different rubber compound than the 17" tire to allow it to last 80K? If not, wouldn't this mean the whole mileage rating thing by tire makers is nothing but a scam?
Are mileage ratings nothing more than a guess?
- Thread starter grampi48
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Disclaimer:
Actual mileage may differ due to driving habits, vehicle conditions, and road conditions.
Actual mileage may differ due to driving habits, vehicle conditions, and road conditions.
There is a government mandated test for the ratings, so at least in this regard it is a good basis. The test consists of testing the candidate tire against an SRTT (Standard Reference Test Tire), and the tires are swapped back and forth between two vehicles.
But because of the size thing that you mentioned (the SRTT is a medium size), the rating has to be "traceable" to the test in some way. Put another way, if the tire to be tested is way bigger than the SRTT (or way smaller), then you can't find a vehicle that will work.
But frankly, this wear rating thing is just for comparisons, and trying to make too much of it is just wasting time. If you compare 2 tires, both the same size, then you've got some valid comparison.
Put another way, most tire wear occurs in cornering, so the more time you spend in the city, the worse your wear will be. This by far is the largest factor in determining what your ultimate mileage will be.
I've seen the cheapest of the cheap tires get 100,000 miles just because they drove 99% on the interstate.
This also applies to alignment. Too much toe-in is just like driving the tire sideways - not good for wear.
But because of the size thing that you mentioned (the SRTT is a medium size), the rating has to be "traceable" to the test in some way. Put another way, if the tire to be tested is way bigger than the SRTT (or way smaller), then you can't find a vehicle that will work.
But frankly, this wear rating thing is just for comparisons, and trying to make too much of it is just wasting time. If you compare 2 tires, both the same size, then you've got some valid comparison.
Put another way, most tire wear occurs in cornering, so the more time you spend in the city, the worse your wear will be. This by far is the largest factor in determining what your ultimate mileage will be.
I've seen the cheapest of the cheap tires get 100,000 miles just because they drove 99% on the interstate.
This also applies to alignment. Too much toe-in is just like driving the tire sideways - not good for wear.
YUP, very educated one but a guess. You can vary it all by weight ratings and what not. Say you have a P205/60R15 102T and a P205/60R15 118T tire both with UTOG 380 A B Ratings. The latter will last longer on the same car just due to its high load rating. It will not be working as hard as it is designed too. So it will only work at a 50% of design load say instead of 75% load.
Not to put too fine a point on this, but in reality, you will never really be able to see better mileage from an Extra Load tire compared to a Standard Load. The difference is small compared to the effect you'll get just by your driving habits.
Not that I think using an XL in place of a SL is bad. Quite the opposite. I just don't think one individual ought to be making a buying decision solely based the difference in wear rate.
Also the wear rating varies by manufacturer
say a michelin tire has a wear rating of 260
another michelin tire has a rating of 480
these are comparable.
but not comparable to a goodyear tire with a
rating of 360... you can only compare ratings
on tires from the SAME manufacturer.
say a michelin tire has a wear rating of 260
another michelin tire has a rating of 480
these are comparable.
but not comparable to a goodyear tire with a
rating of 360... you can only compare ratings
on tires from the SAME manufacturer.
To some degree Rand is correct considering they are comparing to the same US Government reference tire they should be close. So say a Michelin 400 vs a Goodyear 380 the Goodyear may last longer (probably should have given this example the other way but hey) but a Michelin 400 will outlast a Goodyear 200 under the same conditions it is just the fine tuning in the numbers that is rough. So do not necessarily get a tire because this one is 240 and that one is 220. You may find that a 340 is an 60K tire and and a 400 is a 50K tire, but once again that is only its warranty, not indicated milage it can go. Most 400 rated should outlast a 340 any closer I'd say a wash.
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