When do you guys change tires - wear bar, etc

Nice video, very interesting, but I have some questions for the experimenters

What is stopping peformance like at 6/32"? 8/32"? 3/32"?

If the legal limit is raised to 4/32", will they return in two years showing the same effect compared to 8/32"?

I don't like riding tires down to the 2/32" limit under most circumstances for a whole lot of reasons, but I would like to see the whole regression analysis in 1/32" increments at least. It would seem to make more sense to pick a point on the curve where braking distances begin to increase dramatically. If that point happens to fall on 4/32", that's a lucky(?) guess, but I'm a little underwhelmed by the design of this experiment.

If a tire company is going to get involved, donate a set of tires, a truing machine (lathe) and spend a day at the track. Set a base line with brand new tires and start cutting and running from there. Perhaps the slope will not be linear, perhaps it's not linear between 4/32" and 2/32".

Or would we find that performance doesn't really drop off until the wear bars fully block water flow up the tread channel? It's just an alternate hypothesis for the sake of argument mind you, but if you had cut out the wear bars with a tire grooving iron, what would have happened to stopping distance? Anybody want to suggest it would increase?

Yep, if your goal was to improve the safety of the general driving public without necessarily having a goal of selling more tires, I could think of two or three factors to evaluate before recommending an automatic replacement at twice the current legal limit.
 
Whenever I feel that traction is no longer in its best condition, wet or dry. That usually means around 3/32. I do keep the newer tire up front to match the need for the traction on my FWD cars.

But usually my tires blow out on hwy due to sidewall cracks way before it wear down to 3/32, so I buy the lowest trend wear tire on the market. What is the purpose of a long lasting tire if the sidewall cracks?
 
In reviewing this video with other folks, the question came up - and perhaps this is a good place to ask it.

Is it common knowledge that traction in wet driving conditions degrades as a tire wears?

Put another way: Is this video going to be the first time average folks would have heard this?
 
Quote:

In reviewing this video with other folks, the question came up - and perhaps this is a good place to ask it.

Is it common knowledge that traction in wet driving conditions degrades as a tire wears?

Put another way: Is this video going to be the first time average folks would have heard this?


Click to expand...


I would be surprized to find that the "average" driver is cognizant of the fact that traction is degraded by a wet surface (that is, up until the point they are doing 360's down the highway) much less that things get worse with wear. For an important fraction of the population, this lesson must be relearned every time it rains. Many of them live in California.

Of course, I don't actually know any of those people, all the drivers I meet are *above* average.
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Perhaps I'll pose the question to the next 10 people I speak to today. For those that answer correctly, *then* I'll ask them what the tread depth is on their front tires within +/- 1/32".

My guess is that if the basic knowledge test doesn't get the average person, then the applied knowledge test will.
stooges.gif
 
Common knowledge or concern? How many times have you been behind one with sparks coming from the steel belts? Here, in SC, we don't have inspection laws so we can't get these people off the road. Statistically speaking, how many accidents are attributed to tires? In SC, records such as these (tread depth / condition) aren't even kept. There is a section for "Tire Defect" which is usually meant for a blow-out or failure (tread separation) or whatever. Personally, I used to look at the tread at accidents but there was nothing to help me indicate that it played a factor in the cause of the accident (unless obviously bald or whatever). Most "slick tire" tickets I wrote were dismissed if the violator corrected the problem.
 
Quote:



I would be surprized to find that the "average" driver is cognizant of the fact that traction is degraded by a wet surface (that is, up until the point they are doing 360's down the highway) much less that things get worse with wear. For an important fraction of the population, this lesson must be relearned every time it rains. Many of them live in California.



Click to expand...


Really? I could swear that they all live in GA. We go thru periods of drought and every time it rains after a period of dryness (actually, don't have to be a long period either), 90% of the people don't know how to drive anymore.
mad.gif
 
Quote:

Quote:



I would be surprized to find that the "average" driver is cognizant of the fact that traction is degraded by a wet surface (that is, up until the point they are doing 360's down the highway) much less that things get worse with wear. For an important fraction of the population, this lesson must be relearned every time it rains. Many of them live in California.



Click to expand...


Really? I could swear that they all live in GA. We go thru periods of drought and every time it rains after a period of dryness (actually, don't have to be a long period either), 90% of the people don't know how to drive anymore.
mad.gif


Click to expand...


Yeah, a 5pm thunderstorm on the North Perimeter is roughly equal to the traffic problems that would be caused by a small nuclear attack on Buckhead.
crazy.gif
 
When driving in the rain gets excitng, or when the tires experience structural damage, which feels like a thump or an imbalance which cannot be balanced out.
 
When any one tire gets sketchy in any way I replace all 4. This has only happened once, with uneven wear that got worse after an alignment.

I would toss tires after 5 years or some mileage number just due to the aging of rubber compounds but it has never come to that. As I only buy summer high performance tires and winter tires, both of which tend to have compounds that do not last forever I never really hit those limits
 
I live in a rather moderate climate (TN), so I use All Season tires all year. I usually buy so-called "Touring Tires". My own casual research and personal experience is that 4/32" is a good time to change tires. I typically buy Michelin tires, which start with a rather "hard" rubber compound, so time & environmental aging (which increases hardening) is of particular concern also. Most of this has been well documented above.

Another feature that I now look for in new tires are full-depth SIPES. Sipes are the little cuts that typically run across the main tread or diagonally to it. Lower-grade tires typically have sipes that only go halfway down the tread, whereas higher-grade tires have sipes that go down the full tread depth. I'm told that sipes are designed to open under pressure and can make a significant difference in both wet and dry handling, but especially wet braking. From my own experience, I think that this is true. Sipes do not make as big of a difference as the depth of the main tread channels, and justifiably do not get as much attention. However, if you have had tires where the sipes wore-away at half tread-depth I think that you probably noticed a decrease in wet braking performance.
 
I'm down to about 2/32 in the front and 3/32 in the back after 45k miles on the Goodyear Allegras.

I think I'll rotate them and run them until next summer (another 5k miles).
 
I know but the search for 'wear bars' in title only yielded just this thread.

I hardly drive crowded interstate roads and my tyres are AA traction rated. So, I run them to the point of slicks on the front. I drop the PSI 4-5lb once I'm down to the bars. Practically doesn't snow here and in rain or wet roads I modify usual driving style accordingly.

I change the rear tyres shortly after hitting the bars though in summer, dry season, I'll stretch them out as well. I'm not concerned with understeer as much as I am about the rear end breaking loose in a corner.
 
I usually run mine to the treadwear indicators. 5K miles ago when I went to Discount Tire for the free rotation they tried to sell me 2 new tires to replace ones that were down to about 6/32nds. I ran them another 5K miles and went to get them rotated again Saturday. The salesperson this time said I didn't need new tires yet but would soon. This time he said they measured 5/32nds and as I recall that's the reading I got the last time I checked the tread depth. I'm expecting to get at least an additional 15K+ miles out of them from the time they first told me I needed to replace them. If I did a lot of highway driving at 70-80 MPH I'd probably change them earlier but, most of my driving is on rural roads in the 40-55 MPH range and I seldom drive over 50 MPH on wet roads. Discount Tire recommends changing tires at 4/32nds.
 
Sayonara_Sonata said:
I know but the search for 'wear bars' in title only yielded just this thread.

I hardly drive crowded interstate roads and my tyres are AA traction rated. So, I run them to the point of slicks on the front. I drop the PSI 4-5lb once I'm down to the bars. Practically doesn't snow here and in rain or wet roads I modify usual driving style accordingly.

I change the rear tyres shortly after hitting the bars though in summer, dry season, I'll stretch them out as well. I'm not concerned with understeer as much as I am about the rear end breaking loose in a corner.
Click to expand...

Dude, you just resurrected a 13 year old thread!

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Yeepers, I hope everyone changed their tires since this thread was last posted in!

I change around 4/32's. Wet traction is dropping. If I did nothing but city driving I'd be tempted to take down to 2/32's (wear bars) as hydroplaning wouldn't be a problem. But I do piles of highway driving and I'd rather have the extra traction.
 
The fall following 6/32. I try to go into snow season on new tires. This year, 6/32 translates as 40,000 miles. Some vehicles will be more but that's as early as I can remember. I may be a little eager since I HATE this set of OE tires.
 
No good on hydroplaning, but the silica in AA rated helps a lot. As well polyurethane lower motor/tranny mounts make a world of difference in traction on FWD. If you do not mind the vibration at idle and even worse in reverse.
 
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