Ok please correct me if I am wrong, a lower number usually means a softer tire. In exact terms a treadwear rating refers to the rate at which a tire wears out. It is not a measure if the actual hardness or softness of the rubber. Now my question is, if you have a 245 tire with a treadwear of say 220 would a tire of the same compound actually have a lower number if it was a narrower tire. My guessing is that a smaller tire with a smaller contact patch would wear out faster than a larger tire if made from the same compound tire. Does anyone follow my logic on this? More rubber on the road under the exact same conditions should last longer due simply to the amount of rubber it would take to wear it down.



Now we get to the root of my question. My current tires on the rear of my car are 245/50/16 with a 220 treadwear rating. I managed to eat them up in 6 months of street driving with zero track use. The new tires I just bought and have yet to take down to the tire store are 225/50/16 with a treadwear rating of 420. They are both Traction A, Temp A rated. It kinda worries me that they are both a narrower tire and have a higher treadwear rating. I was prepared for a loss of traction due to the smaller size of the tire and effective gear ratio change. However now I am really worried after seeing my current numbers vs the numbers on the new tires. The only good thing about the whole situation is my transaxles might last a bit longer and I won’t break as many mounts. (3 Isuzu’s in 2 years and engine is now held in by 2 solid mounts, 1 poly mount and 2 stock trans mounts, which will be upgraded to Rodney Dickmans poly trans mounts.





So anyone want to chime in with input regarding traction vs treadwear vs tire size?

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85GT 5spd ,93 Eldorado 4.9 Dual O2 Custom Chip, Archie Clutch. Custom Exhaust. MSD Everything 245/50/16's Not Your Average 4.9 Capt Fiero Com --- My Over View Cadero Pics Yellow 88GT 5spd Stock.

First of all, treadwear ratings are honestly not that accurate. Using treadwear to compare unlike brands of tire is also a bad idea. One trick that I almost fell for was a cheap "drag tire" that advertised a 40 treadwear rating, and it turned out to be a strech just so they could market it as a drag only tire but still be street legal. The research I found showed an inferior rubber compound and a very "street minded" design was really under the skin.

As far as your question goes, here is how I look at it.

If a large tire and a small tire have the same treadwear, then they in turn will have a true result of the same treadwear for this reason. The large tire will have increased friction with the road, and in turn wear more, but the tire is larger and has more tread to wear off of it, which I suppose would cancel out the "less wear" the smaller tire would experience. Also the examples in your situation are very small anyway, your tires may be smaller now, but only by 2 centimeters.

But IMO, stay away from looking too close at the tread wear ratings as they are most of the time misleading. Stick with truly indepentant testing for your tire research.

The tire manufacturers usually dont change the treadwear rating of a tire model between it's sizes, so that rating might come from one specific tire size that has been developed between tire companies as a standard. I think you should get some Kumho V710's . Thats what i was gonna get but they didn't have the sizes i wanted, treadwear of 30. I had to settle for V700 Victoracers treadwear 50.

Lower number indeed does not necessarily reflect a softer compound. It reflects a shorter "expected" life in comparison with other tires in that brand's lineup. 220 in a Pirelli won't be the same as 220 in a Goodyear. Only way to compare compound would have been a durometer test on both (when new). Still, you have the difference in tread pattern, which will have an effect on traction. Your 245's could have been understated to appeal to performance minded folks. The 225 size is going to appeal to a much broader market- it may be overstated to appeal to folks who want a long lasting tire.

To answer your question on the 225 wearing faster than a 245- All things equal, I could make an arguement for the 225 lasting longer because the narrower contact patch wont scrub as hard as a wider tire in a turn.

Well I went down to my fav tire shop. "Tom The Tire Guy" which is a privately owned and operated single tire store. Not a big chain store. I showed him the tires and he looked at my old bald 245's on the back that he had sold me last spring, he kinda shook his head that I ate them up that quick. He checked the tires over that I brought in and showed me the DOT number on them to make sure they were not some of the junk re manufactured tires that are being sold around here. He checked the ratings on the tires and told me they are very similar to some Yokohama tires he gets for customers. The end result of it, he said they are a really decent tire. They should probably do my car fine.He ended up doing the mounting and balancing on the house, which was really nice. I guess being a long time customer he still tries to take care of car guys.

So I got them on the car, and left. The snow was starting to thin and the ground was only wet. (yes it snowed this morning) First thing I noticed is the sidewall is much firmer with these tires. The back end felt more planted. I did a rolling start in 2nd and punched it, with my old tires the back end would have been all over the place in the rain, however they seemed to hunch down had a bit of controllable wheel spin and then grabbed and took off. I am very impressed. For the record they are "Fierce" brand 225/50/ZR16's I posted a pic of the tread pattern when I first got them. I will see if I can find the pic and repost it.

Thank You everybody that posted info about the treadwear stuff. He confirmed what you all said. The treadware is only a guidline and is not even close to an exact spec for a tire. Every brand seems to have a diffrent way of justifying what they feel is the rating and it can vary widly. I guess it is kinda like jeans. A 34 waist Levi won't be the same as a 34 waist Wrangler. Best to try it out and see how it fits.

Edit to add pics




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85GT 5spd ,93 Eldorado 4.9 Dual O2 Custom Chip, Archie Clutch. Custom Exhaust. MSD Everything 245/50/16's Not Your Average 4.9 Capt Fiero Com --- My Over View Cadero Pics Yellow 88GT 5spd Stock.

[This message has been edited by Capt Fiero (edited 04-02-2007).]