How many treadwear miles do we REALLY get for every 100 UTQG points?

On Sat, 25 Aug 2007 17:51:55 -0400, Nate Nagel wrote:


I live near Pleasanton California where it almost never rains nor snows. Well, it rains a bit in the winter but never in the fall, summer, or spring. It's pretty flat so there are no hills, nor do I drive on dirt roads. My car is a Toyota Camry, year 2000 and I've the stock size tires and wheels. I drive like a little old lady mostly around town and not much on the highway. When I drive on the highway, I stay below about 85 as my limit. Around town I try to avoid sudden starts and stops and I never spin my wheels nor do I leave skid marks on the road. Still, I don't get anywhere near the 30,000 miles per index 100 for my tires, having been through two full sets of tires in the 85,0000 miles I've driven since I bought the car new. I buy my tires where I get free balancing and rotations and about twice a year I take them in for the tests. I had the car aligned twice since I bought it and the shocks/struts have been replaced about a year ago. I keep a tire gage in my glove box so when I fill the tires about every few months, I check to keep them at the right specification that I read off the door panel. I get about a flat a year (on average it seems) and they have to repair the tire from the inside (sometimes it's too close to the edge and they have to throw the tire away).
I'm not sure what else matters. What else would you need to know?
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_Prina, I find this quite interesting, and I've been lazily waiting for a valid answer to your question--it's been on my mind, on a back burner I must admit, but has nonetheless bothered me over the years. The most explanations I've received from tire dealers is the 'relativity excuse'--i.e., a 200 theoretically goes 2 times the miles as a 100-rated tire. My dad sold tires and I sold cars. At one time I would install the el cheapo tires, like those with a 220 twr(treadwear rating), on cars I was sending to auction. After all, if they weren't Michelins, new tires were just that--new tires (We only knew of 1 'quality' tire in my area.). But after I saw 2 customers wearing those same tires(not sold by me): (1) have a blowout while sitting at a red light in hot weather; and (2) another have a blowout riding in town at about 35 mph; both these tires blew out on the sidewall, of all places. I quit even using them on the auction-units! My customers and my family and I never have gotten the mileage wear advertised by that belief in 30k per 100 rating. One actually did get 60k on a set of 60-k Michelins on a '95 Riviera, but I refused to ride with him for the last 10-15k miles. Like you, I feel there must be some percentage we can use to help determine the actual miles to "really" expect. Even twr's will differ among mfgs--I don't wish to beat them down, but "Energy Men" stores will put a 500 twr on a tire that won't give but about 60-70% the miles that a 500 Michelin will give. My guestimate therefore would have to be for a given mfg. Michelins, for instance, I'd guess like you: using 500 to indicate 5 times the 30k, or 150,000 miles, I'd estimate about 1/2 the theoretical 150k, or 75k at best--in our state, the last 2/32 inch of tread legally must be replaced! My friend who got 60k from his Mich's was using Summits, and the 60k he quoted me was what the selling dealer had told him--but the twr was way higher than 200--which would've been twice the 30k from the 100 twr. IIRC, his twr was about 400. Using the relativity model, that would suggest 4 times 30k, or 120 k. And 1/2 of this 120k would be the 60k he actually got--some miles from quality and some miles from prayers! I used to buy a metric-design tread from Western Auto--made pretty tires for Taurus's etc.--and IIRC their twr was about 320. We ran a set on an ~'87 model Taurus. With about 20k on the tires, we sold it to a local company. Seems like they asked me to get them a new set of tires when they had put about another 10k on them, for a total of 30k miles. This rates about 96k based on the 100 giving 30k, and works out to be a factor of about 1/3 actual miles as based on the 96k theoretical miles. These were cheap tires, and may have had a much-inflated rating like the "Energy Men" ratings I mentioned earlier. Then one exception I must toss in: a friend who bought a new Explorer and drove it on many daily 200-mile round trips, got an unbelieveable 130k on a set of Firestones. He then traded it to the local Toyota store, which cleaned it up and put it on their budget lot--with the same tires, just polished to give them a glossy appearance. My final analysis from all this bs is that one would at least have to use a different set of parameters, and percentages, as he moves from one mfg. to another. But we can be assured of one thing: that model of 30k per 100 rating can NOT be relied upon. Even if we stick to one brand, the %'s are going to vary as we go from one temp. rating to another and from one traction rating to another. Now to introduce another problem that prevents our getting as many miles...those damnable flat spots that occur and create such roar and bumping, even with 2/3 the original tread depth still remaining. Can we legally claim 2x their original cost?...or 3x the orig. cost?...as a charitable income tax deduction? I cried every time I had to "donate" so many over the years that I'd think it reasonable to claim some % of their original cost to pain and suffering!!! This whole theme seems to just defy all scientific criteria. Unless we defer it to "social science"!!! All my 2 cents' worth, and often worth every dime. sam
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Just a data point.
1999 4dr Olds Alero 3400 V6, purchased new. Factory original BF Goodrich Touring T/As.
P215/60 R15 TPC Spec 1139 M/S Treadware 380 Traction A Temperature B
This car has 107,500 miles on it and while obviously worn, none of the tires are down to the tread wear indicators in any groove. Tires are wearing extremely evenly, have been rotated maybe 3 times in the life of the car, although the fronts of course wear quicker than the rears on this front wheel drive car. Rain and dry traction still excellent, even in resistance to hydroplaning in standing rain water. Wheels seem to be exceptionally well aligned, although it has never had a wheel alignment and was in one moderate collision to the right front corner. This car rolls very easily, when you lift at 45 mph it slows -very- gradually.
Location is Evansville, Indiana, miles have been about 75% city, 25% highway. About 99 percent paved roads, but roughness, pot holes, rough train tracks, etc. are not unusual.
Lee Richardson Mech-Tech
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Lee, sounds like a car that one of us should hang on to! You are probably also a careful driver who does not punish a car during takeoff or the brakes during stopping. Keep it up! BTW: How do you like that 3400? s
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True, I drive like an old man, because at over 50, I guess I am one.<g> Also in an attempt to keep fuel costs down. But it has had several full throttle blasts throuhout it's life. The engine is great, except mine has the leaking intake gasket. It was replaced once under warranty, and it has been leaking again for the past 20,000 miles. Not a lot, but just enough to let me know it is leaking. I have used a total of 2 gallons of 50/50 Dexcool since the second leak began.
Lee Richardson

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You appear to have a terrible misconception of the scientific method. People have given you good answers. I don't know why you choose to ignore them. Nothing other than BS has come up saying that 100 = 30k miles.
If you actually use the scientific method to find out how long a tire will last under certain conditions, you need to subject a tire to those conditions until it wears out. Then you get to repeat the experiment again and again. If the results are pretty consistent, then you *might* have the right answer.
http://en.wikipedia.org/wiki/Scientific_method
But guess what? Even if they did test the tires until they wore out, there are still all kinds of variables that are different in your case. You are driving in CA, not TX. Your car is likely not the same model. The weather is not the same, etc, etc...

Which of the newsgroups you cross posted to are you talking about?

Yes.
Ivan
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_Pnina Gersten_ wrote:

The test tire rated 100 is or was a bias ply, and my Goodyear Polyglas bias ply tires lasted almost 20,000 miles.
Michelin 140: < 40,000 miles Goodyear 140: < 40,000 miles Dunlop 220: > 50,000 miles (tires replace due to age, not defects or tread) Cooper 560: 35,000 miles Discount Tire 300: 45,000 miles Michelin 740: 88,000 miles (still in use, 3/32" tread remaining)
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I'll bet if you drove all 150,000 miles in a conservative manner on the same test track you get close to the rated mileage. But the real world is not a test track. There used to be a study that compared tire wear state by state. My home state, NC, was rated near the bottom, mostly because so many secondary roads are recoated with a rock and tar mixture. This leaves a lot of sharp edges exposed that really wear out tires. My ex-wife used to shred tires at an incredible rate. She never, I repeat never, drove on a major highway. If she needed to get from point a to point b on the other side of town, she would wind through all the obscure highly cambered, twisty surface streets she could find. Tires that would last me 50,000 miles would not last her 20,000 miles. Your driving style also affects tire wear. Lots of quick starts, heavy breaking, and high speed cornering will wear out tires much more rapidly than conservative driving. My Sister had a 1980 Honda Accord. She actually had the car shipped to Europe when she worked their for 2 years. When she was back in the states the car was totaled in an accident. It had around 80,000 miles on the odometer. There were rust holes in the body, the car rattled and whistled like a banshee, the muffler had holes you could stick your hand through, but the tires were original and still had enough tread to pass inspection. My Sister just doesn't wear out tires. I think she is averaging over 60k on the cheapest tires she can buy for her current Honda Civic. The type of car also has an effect. I had a 1978 Ford Fiesta. It came with 12" Michelin tires. I read a recommendation that you should never rotate the tries for this car, rather just replace the front ones when they wore out. This is what I did for the first 8 years. Finally when the car had 130,000 miles on the original rear tires, I moved them to the front so I could wear them out before they dry rotted. The fronts were only good for about 40,000 miles per set (Michelins). I think if dry rot wasn't a problem, the rears would have out lasted the rest of the car.
Ed
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