Shaved tires last longer. Myth, or true?

[slugg]

For autocross and street tire racing applications, I've heard from many sources that shaved tires somehow last longer than brand new, unmodified tires. I fail to see how this is even remotely possible. Anyone care to explain, please?

 

[skyking]

Tires are built to fairly good standards, but you can "true" them up to much closer tolerances when mounted on the wheel and inflated. Rounder = less stress.

 

[Batmeat]

I don't know about shaved tires, but siped tires do.

 

[slugg]

But truing = less rubber. This is counter intuitive and the reason for my confusion.

 

[helpme]

This can be true if a full depth tire "chunks", or has pieces ripped off when the tread flexes. Once you shave it, the depth doesn't allow the same flexing, and no chunking.

A shaved tire and a full depth tire used on the track may actually see the same useful life. The rubber will harden after so many heat cycles, and the user may stop using them before the actual tread is gone. Thus, shaving them gives you more grip through the life of the tire (less tread squirm) even though you have less "rubber".

 

[phucheneh]

I don't know about shaved tires, but siped tires do.

You sure? IIRC, sipes are for better traction on all surfaces. But better traction = increased friction.

This is where I've always been a little confused. I think I'm right, but unsure. Obviously, 'kinetic' friction, i.e. spinning tires, will wear the rubber off faster.

'Static' friction should not. But just because the tire does not lose grip with the road surface does not mean it's all static friction...I had an argument with a teacher over this once...I argued with teachers a lot...go figure, right?

If a tire only had static friction as it rotated in contact with the road surface, it would not wear. This is obviously observed when you compare front tire wear vs rear tire wear- rears wear way more slowly because the tires don't rotate on a vertical(ish) axis like the fronts, which will scrub against the pavement. They (rears) have less kinetic friction with the road.

But obviously rear tires still wear out. I believe a large contributing factor is the sipes, which allow the tread blocks to 'squirm' and rub against the pavement individually, increasing grip.

Slicks (or tires made before siping was common) still wear because the tread compound has to be much softer. Modern compounds can be harder, but would not provide adequate traction without the sipes. Assuming you stayed within the the tire's limits (didn't break traction), a tire of the same compound without sipes should wear slower...I think? Makes sense to me, anyway.

What I've wondered more is how much 'spirited' driving (again, without breaking traction) increases tire wear. I go around corners much closer to the, uh....'tractional limits,' than your average person, but I still seem to get good tread life out of tires.

One thing I know for sure- driving the car harder wears the tires a lot more evenly. I've seen a LOT of people driving fairly high performance, good handling cars who shouldn't...they take corners like an old lady. Said handling often includes fairly aggressive alignment angles, which increases the likelihood of uneven wear- inner tire wear from negative camber, or 'chopping' (don't know a technical term...when a tire looks like an angled paddle wheel) from a lot of toe-in or toe-out.

I saw this sooooo much with the G35/37's. People...okay, I'll say it...often women...buy them because it's a relatively cheap car with a luxury badge. But they are great handlers...that get gingerly driven. I've seen new front tires destroyed before you can even get to a 7500 mile rotation. So much toe wear that they roar like both front hub bearings are bad.

edit: Oh yeah...the OP...I dunno. But I've never been a believer that imbalance/runout (related but not the same) wears tires faster. The heavy (or high) spot in the tire will 'hit' the road harder, but I don't think that's going to make it wear noticeably faster. Especially if the tires are FAIRLY round (i.e. not cheap pieces of shit) and balance is properly corrected with weights.

And I don't see how they'd increase traction at anything other than very high speed cornering.

 

[jlee]

rears wear way more slowly

lolwut?

()

 

[Ferzerp]

lolwut?

()

Seriously....

The weather is getting cold, traction is going down, power is going up. Rear tires going screeeeeee even when I don't mean to sometimes.

 

[phucheneh]

If you drive a [RWD] car with traction control, it's not even remotely possible to wear rear tires faster than fronts. If you turn it off/don't have it and just spin your tires like a 16 year old all the time...well...grow up?

 

[Meghan54]

For autocross and street tire racing applications, I've heard from many sources that shaved tires somehow last longer than brand new, unmodified tires. I fail to see how this is even remotely possible. Anyone care to explain, please?

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=67

 

[EightySix Four]

If you drive a [RWD] car with traction control, it's not even remotely possible to wear rear tires faster than fronts. If you turn it off/don't have it and just spin your tires like a 16 year old all the time...well...grow up?

lolwut?

 

[Ferzerp]

If you drive a [RWD] car with traction control, it's not even remotely possible to wear rear tires faster than fronts. If you turn it off/don't have it and just spin your tires like a 16 year old all the time...well...grow up?

People claim that childhood is the happiest time of our lives, but then people also criticize what little fun we do have.

I recognize that you're new here, but you've been here long enough to know that there are quite a few of us here who have cars that can leave pretty much entire tires on the road if we really feel like it.

And yes *gasp* occasionally we might actually cause them to spin. (and as I alluded to, not always on purpose as the weather turns colder)

 

[exdeath]

Spinning sux.

 

[Mutilator]

^ What they said about spinning. Or my car is broken because for some strange reason I go through rear tires twice as fast as my fronts even with traction control on.

Performance summer tires are great until it gets below about 40F... then they scream in pain (or is it pleasure? ) if you even think about touching the accelerator.

 

[slugg]

Back on topic.

I can't find any empirical evidence anywhere that supports the claim of shaved tires lasting longer than unmodified tires. Tire Rack's informational page does not explain why shaved tires last longer in high performance applications.

Okay, so there's less squirm in the tire tread. So why not wear the tire down to 6/32" naturally rather than shaving? Has anyone done any tests to show the difference in durability? So far, through my searching, I have found no reason to believe that shaved tires last longer than normal tires. It's all speculation; zero evidence. Can someone show me otherwise?

 

[Zenmervolt]

If you drive a [RWD] car with traction control, it's not even remotely possible to wear rear tires faster than fronts. If you turn it off/don't have it and just spin your tires like a 16 year old all the time...well...grow up?

Even if you never so much as chirp the rear tires on a RWD vehicle, they'll usually wear faster. The driven tires almost always wear fastest.

Severe wear on the inside of a tire is caused much more by excessive toe-out than it is by any reasonable camber setting; the camber has to be off by pretty ridiculous amounts or combined with excessive toe out before you'll get inside wear. I've seen plenty of cars with 2-3 degrees of camber and no abnormal tire wear because they didn't get crazy with toe settings.

I'm not sure what you mean by "chopping" as the description is vague. The only things I can think of are either cupping or feathering.

"Cupping" is generally caused by either weak/worn dampers (shock absorbers), an unbalanced wheel/tire combination, or bearing wear in the hub. These are all conditions that allow the tire to "bounce" more than normal which is what causes cupping.

"Feathering" (where the tire feels sort of "serrated" when you run your hand across the tread width) is indeed usually caused by excess toe (either in or out), so I think that's probably what you mean.

As far as your idea that driving the car harder makes the tires wear more evenly, that's just absurd for most vehicles, especially family vehicles where the handling balance is generally severe understeer and driving the vehicle harder simply induces ridiculous amounts of slip in the front tires and burns them up incredibly fast. The amount of side-slip that a typical FWD family sedan will see on the front tires when driven hard is incredible and it's certainly not going to make the tires wear evenly. It's just going to beat the ever-loving crap out of the outside front tire on every corner.

What keeps tires wearing evenly is regular rotation.

ZV

 

[phucheneh]

I'm aware that rotating your tires is necessary. I was pointing out that some people drive so gingerly that some cars (again, usually performance cars with more aggressive suspension setups and alignment specs) will wreck tires with abnormal wear before the first normal rotation interval.

Re: everything else about tires and alignment...you don't know what you're talking about. Sorry. Not feuding with you anymore. You're just incorrect and I'm done feeling the need to explain why.

edit: also, you're not smarter than everyone else. Sorry, someone had to tell you eventually. Maybe it's just me that you constantly condescend to with your 'input.'

 

[soccerballtux]

seriously....

The weather is getting cold, traction is going down, power is going up. Rear tires going screeeeeee even when i don't mean to sometimes.

fwdftw camry or bust

 

[soccerballtux]

Back on topic.

I can't find any empirical evidence anywhere that supports the claim of shaved tires lasting longer than unmodified tires. Tire Rack's informational page does not explain why shaved tires last longer in high performance applications.

Okay, so there's less squirm in the tire tread. So why not wear the tire down to 6/32" naturally rather than shaving? Has anyone done any tests to show the difference in durability? So far, through my searching, I have found no reason to believe that shaved tires last longer than normal tires. It's all speculation; zero evidence. Can someone show me otherwise?

tirerack wants you to buy more tires maybe.

 

[sdifox]

I don't undestand how it makes any sense. shaving might improve balance thus making the ride smoother, but that is a lot of wear right there.

 

[Ferzerp]

They do actually give you a reason (with no evidence). Whether or not you believe it is another story.

(This is a summation of their explanation, not my own, I am making no judgment on the accuracy of this information)
Wearing it down naturally, has a negative effect on the remaining rubber due to the flexing associated with the taller tread. If it is shaved down, you end up with a better set of remaining rubber that will last longer due to being under less stresses the whole time.

The stress of the taller tread has an impact on the rubber throughout the tread.

(My own view here)
While their hypothesis sounds plausible, it would require some actual testing for me to accept that view.

 

[Zenmervolt]

I'm aware that rotating your tires is necessary. I was pointing out that some people drive so gingerly that some cars (again, usually performance cars with more aggressive suspension setups and alignment specs) will wreck tires with abnormal wear before the first normal rotation interval.

Driving gingerly will never wear tires faster than driving aggressively. Driving more aggressively may, in some very rare cases where cars have extreme camber and/or toe settings, distribute the wear more evenly across the tread width by forcing the tire to straighten up in corners and thereby putting more wear on the outside of the tread, but the more aggressive you get the greater the slip angles and high slip angles cause massive wear.

Re: everything else about tires and alignment...you don't know what you're talking about. Sorry. Not feuding with you anymore. You're just incorrect and I'm done feeling the need to explain why.

Sorry kiddo, but that's just not true. I've been running 2 degrees negative camber on the front of my 951 for almost a decade now and never go above probably 7/10 in street driving, yet the street tires show no abnormal wear. This is because I have not been too aggressive with my front toe out settings.

High toe-out magnifies the effects of extra camber and while camber alone, at very high settings that should never be seen on the street, can cause wear on the inside of the tire, the most common way for the inside of the tire to wear in my experience has been for a person to have only mild to moderate camber settings and excessive toe-out.

It's not about "feuding," it's about correcting the absolute twaddle that you put in about 10% of your posts. Based on your posts here I wouldn't let you work on a lawn mower, let alone a car.

ZV

 

[jlee]

If you drive a [RWD] car with traction control, it's not even remotely possible to wear rear tires faster than fronts. If you turn it off/don't have it and just spin your tires like a 16 year old all the time...well...grow up?

Tell that to my MR2.

 

[phucheneh]

They do actually give you a reason (with no evidence). Whether or not you believe it is another story.

(This is a summation of their explanation, not my own, I am making no judgment on the accuracy of this information)
Wearing it down naturally, has a negative effect on the remaining rubber due to the flexing associated with the taller tread. If it is shaved down, you end up with a better set of remaining rubber that will last longer due to being under less stresses the whole time.

The stress of the taller tread has an impact on the rubber throughout the tread.

(My own view here)
While their hypothesis sounds plausible, it would require some actual testing for me to accept that view.

I could possibly believe something along the lines of: The top of the tread wears more quickly because of increased 'squirm;' so it doesn't matter that much if you shave some of it off.

But I don't. Experience says that it appears to be the other way around- long-lasting tires can appear quite 'new' for a decent amount of time, but once the tires are about worn out, the remaining tread disappears quite quickly. I'm pretty sure that's because the rubber gets softer as you get closer to the belts.

At least that's my opinion on it. Like I said, that's just what it seems like I've observed. Also, I worked with a guy who built tires at a Goodyear plant before things were as automated as they are now, and I think that was among some of his vast tire knowledge that he shared. His info always seemed pretty reliable. The manufacturing process may have changed, though.

In another kind of backwards move, I think having tires built by hand (I mean, there are machines, but no automation) turned out a better product. 'Hand-made' usually means that...but for something like a tire, I would think robots, computers, and such could do the job more precisely. Yet I've seen the quality of tires steadily decline as time goes on. More runout in every direction, even on high-end brands.

I've always felt Michelin was the best you can get, as far as quality. Their tires were always round, with very little to no radial runout and never any laterally. Never saw a Michelin tire's tread wave back and forth as it spins on a balancer.

...until the last few years. Now they seem to have as many problems as anyone else. I mean, yeah, you're more likely to get good tires than with, say, Hankook, who's always been hit-and-miss. With Hankook, they're capable of building good tires, but they appear to lack strict quality control standards. I guess Michelin has simply lowered theirs, as well. Probably all about being price-competitive with Korea (and now China...man, those are some truly awful tires).

You don't want to know how many high-end tires from brands like Michelin and Bridgestone I've taken off of (expensive) cars during pre-delivery inspections. If somebody's going to pay 70k for a car, you can bet your ass it's not getting my stamp of approval if it vibrates on the interstate.

 

[phucheneh]

Tell that to my MR2.

I guess the RWD cars I've owned, and the ones I've worked on, have all just been exceptions to this 'drive wheels wear tires more' rule.

While there may be exceptions, the 'rule' is that the steering tires wear faster. I've watched a LOT of cars go from brand new to their first set of replacement tires and on. Never seen rear tires wear faster. And I always put the most tread on the front...that's another rule people get backwards. I love when people argue with me about 'best tires on drive wheels' vs 'best tires on front.'

Yeah, getting good traction at the drive wheels is totally of the highest importance on a car that can't steer...