Thinking about new tires? read this:

[cyclopathic]

http://www.abcactionnews.com/money/c...ranty-promises

The tests found some tire claims are too optimistic.

Consumer Reports says a Kumho tire with a 75,000 mile warranty should only last around 55,000 miles; a Continental tire with a 90,000 mile warranty projects a tread life of 60,000 miles; and a Nokian tire with a 80,000 warranty will wear out around 35,000 miles.

The tire tests also revealed some tires will exceed their manufacturer warranties.

"Michelin was a standout," said Rechtin. "The three models we tested all met or exceeded their mileage warranty and came in with a projected tread life of 80-thousand miles or more."

The longest lasting tires in the tests are the Pirelli P4 Four Seasons Plus. Pirelli claims they will last 90,000 miles. Consumer Reports estimates they will go 100,000 miles.

[inuvik]

Good info, not surprising though.

[cyclopathic]

Good info, not surprising though.

I am disappointed with Nokians. Very interested which tire under what conditions they tested. I had Bridgestones in the past which would melt out at high speed on hot day, I suspect could be an issue with Nokians.

Michelines were rocksolid. Last 6 Energy Savers A/S went well over 60k they are rated at.

[25Plus]

I never heard about tire warranties here in Germany. I buy new tires if I have to, no matter how many kilometers they last. And I buy the best tires I can get for my money.

Tomorrow I will get my Continental Winter Contact TS850 tires (165/50 R15), the best winter tires of last years tests. I drive Winter Contact TS800 on my Daihatsu, the tires with the best fuel economy I ever had. The Daihatsu rolls better than the Space Star with the Bridgestone Ecopia. I hope the TS850 will be even better.

[cyclopathic]

@inuvik:
I found more info on test here: http://www.consumerreports.org/cro/m...wear/index.htm

As I suspected they tested it in Western Texas, so heat was likely an issue. So I guess Nokians are off my list. It doesn't get as hot here as in west TX, still 95-100F is norm during summer.

@25plus:
Yeah we have tire warranties in US; at least on paper. Most of the time it is not worth the paper it is printed on. The tire is pro-rated (so if you had 50,000mi tire wear in 45,000, you only get 10% toward new tire), you have to handle warranty through original seller, labor to take tire off and put on is not covered, issues with alignment are not covered, damage due to excessive abuse, racing, under-/over-inflation etc. So if you got tires online most likely it will not worth it your time.

BUT warranty is usually a good indicator of how long the tire can last, so it is part of the buying decision.

[Cani Lupine]

If you want longer treadlife, you trade off traction or rolling resistance. It's kind of like a triangle, with each one at a corner, but you can only choose one side.

Good grip and low rolling resistance? Short life.
Long treadlife and low rolling resistance? Low traction.
Good grip and long treadlife? High rolling resistance.

Now with treadwear ratings, manufaturers have leeway to make their own math a bit fuzzy. The ratings are compared to a baseline 100 treadwear tire, and they do their own calculations based on the remaining treadlife after the 100 has worn out. It's different for each manufacturer, so a 500 treadwear rating for Kumho will be different than Michelin, for example.

With most Michelin tires, I've noticed they do have very long treadlives, but most people don't even wear the tire out by the time dry rot sets in after 5-6 years.

[Eggman]

Good grip and long treadlife? High rolling resistance.

That is an interesting statement. Can you help me understand what factors cause this?

I would guess that a hard compound gives long treadlife at the expense of grip, a soft compound aids grip but wears quickly. What influences rolling resistance? From riding a bicycle, I can tell when my tires need airing up, as I have to put in more effort. Tire pressure being otherwise equal across these scenarios, I would guess that compound hardness would have the greatest effect on rolling resistance, which would be compatible with long treadlife but not good grip. So what combination of factors do you say contributes to both good grip and long treadlife, but high rolling resistance?

[cyclopathic]

That is an interesting statement. Can you help me understand what factors cause this?

I would guess that a hard compound gives long treadlife at the expense of grip, a soft compound aids grip but wears quickly. What influences rolling resistance? From riding a bicycle, I can tell when my tires need airing up, as I have to put in more effort. Tire pressure being otherwise equal across these scenarios, I would guess that compound hardness would have the greatest effect on rolling resistance, which would be compatible with long treadlife but not good grip. So what combination of factors do you say contributes to both good grip and long treadlife, but high rolling resistance?

Read this: http://machinedesign.com/automotive/...ance-car-tires

[cyclopathic]

If you want longer treadlife, you trade off traction or rolling resistance. It's kind of like a triangle, with each one at a corner, but you can only choose one side.

Good grip and low rolling resistance? Short life.
Long treadlife and low rolling resistance? Low traction.
Good grip and long treadlife? High rolling resistance.

That is an interesting statement. Can you help me understand what factors cause this?

I would guess that a hard compound gives long treadlife at the expense of grip, a soft compound aids grip but wears quickly. What influences rolling resistance? From riding a bicycle, I can tell when my tires need airing up, as I have to put in more effort. Tire pressure being otherwise equal across these scenarios, I would guess that compound hardness would have the greatest effect on rolling resistance, which would be compatible with long treadlife but not good grip. So what combination of factors do you say contributes to both good grip and long treadlife, but high rolling resistance?

here is another good write up on this (I assume Cani was referring to it): http://www.barrystiretech.com/rrandfe.html

[Eggman]

Read this: http://machinedesign.com/automotive/...ance-car-tires

I did, and I don't think it helps much. To quote the article,

The most influential factor on rolling resistance is tire pressure.

This is in reference to hysteresis losses internal to the tire. The more the tire flexes, the greater the rolling resistance.