I have a set of yokohama AVS ES100 245/40/18 with approx 8.5k miles.....

Now these tires cost me a pretty penny because they are 18 inch size...but i was wondering how long can I run these until my dry traction is no good? Because i read somewhere about Nealoc187 sayin he ran nearly the same times with any kind of streets tires (i.e. brand new kumhos vs. balded out toyo t1-s)......like basically he said any street tire will perform nearly the same no matter what condition its in....its when you talk about slicks and DRs, then the story gets different....

so what Im tryin to say is, I plan to keep these tires until they are "almost" bald because I really can't afford brand new 18s in the near future....but is it good idea to do this for my traction? for example when i drag race or take the local mountain twisties? I mean i'm not too concerned with wet traction and i know tread is really important for wet....but i live in So cali and the weather here is great, even during the winter.....so is it true that dry traction still remains on the tire even though thread is almost gone?

THANKS FOR READING!

 

I belive general law is that if you have 2/32 tread left, you should replace your tires. Variables such as temp, road surface, how aggressive you drive, punctures, etc will affect your ride also. I say be on the safe side and replace tires when they need to be replaced. They are the only thing keeping your car on the road.

 

I just got a new pair of Nitto 245/40/18 to replace the two that should have been replaced a long time ago. I don't know what the tread depth got down to but it was well past their time.

I didn't really notice too drastic a difference in dry traction between the old and new, but I can assure you rain traction goes to crap, almost to the point of being dangerous.

 

thanks for the replies....i will be sure to keep that in mind.....

on the flip side....i am broke as a motherfu*ker right now....since i had to pay off 2 tickets....and replace my CV boot because i accidently tore it doing a suspension install.....so yeah i'm planning to keep these yokos for awhile....they hold up pretty well....and i'm sure they still will even when the tread is gone.....but they do get pretty noisey after a certain mileage....argh

 

dry traction is mainly a function of the amount of rubber of the road... so unless the rubber compound changes ... dry traction should increase as the tread goes away.. rember that the limit of traction also changes.. with out tread squirm you will not feel the limits of the tire as easy and run the risk of overdriving the tire... for dry use only you can run them to the cords... also be aware the the ride will suck and puncture resistance will be very low... and any water will be like ice.... these are the reasons people don't drive on slicks on the street.... for a daily driver I would still replace the tires at the wear bars...later

 

Physics 101 says that wider tires or more/less tread don't change your traction at all. What matters is the coefficient of rolling friction between the two surfaces- the road and tire. Tire rubber compound definitely effects this, but tire size does not. Increasing tire width or using slicks will increase the surface area of the tire contact patch, but the weight on the tire(your car) remains the same. This means that while you have more tire on the ground, there is less weight per square inch=traction remains the same!

As my physics proffessor said, a top fuel dragster with tires 1" wide has the same traction as one with tires 2' wide (given same rubber compound and conditions). Of course the thin tires would wear out quickly from wheelspin, but that is another matter.

 

Steve - Your dry traction is going to be more a function of age and heat cycling than on tread depth. It'll probably be enough different to show up in ET's (or auto-x run times), but not enough to make a difference in any sane driving on the street.

Mark - Physics 101 is far too basic of a course level from which to discuss tire behavior. Unless your physics prof is thinking in terms of tires with completely undeformable treads (examples that come to mind include steel wheels/casters such as are found on floor jacks and medium-sized safes), his choice of this as an example of friction is poorly chosen at best (IMO, off-base is a more accurate and less understated description if somewhat inflammatory - though he should absolutely have known better).

With tires, nothing is linear and some of the concepts involved are highly variable yet are assumed to not even exist in the typical physics classroom. There are at least 3 components of tire 'grip', "friction" being but one (mechanical "keying" and chemical bonding being others). You'll be better off thinking in terms of an effective "grip coefficient" that's in some vague inverse relation with unit loading. Unit loading is not constant over the contact patch (it can vary by 2:1 even with the tire at rest). Then integrate the grip function with the variable unit loading over the contact patch in its deformed state.

Norm

 

why don't you get some wanli tires? They last a pretty long time, and they are cheap...

 

Hey 1FstmaX....I heard Wanli tires were knock offs of the Yokohama AVS Sports? And I dont go with knock offs....I only go with the real stuff....But anyway I heard Kumho Ecsta Supra 712s were good high performance tires.....and a reasonable price....and i heard they stick like glue......maybe I should check them out?

 

i still say wanli... cant go wrong with that price... besides who comes up to yer car and checks out what tires you got?

 

Me.

And it's with an open mind until I see B's and C's for traction and temperature or a treadwear rating that's more than a couple hundred points higher than what's on the tires that I buy.

Norm