Tire Tread Depth--Penny vs Quarter

[nwsteve]

I was checking tire depth with the Lincoln head technique (if tread covers Lincoln head, you are good with the 2/32), I noticed tires were getting close and maybe had 1/32 extra. Maybe enough for Summer?
Googled tire depth and learned there is considerable stopping and safety advantage to use WA head quarter as the standard for replacement. Quarter provides 4/32 depth vs the penny's 2/32.
Full study results--https://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=85
"This time the repeated runs taught us that the average stopping distance for the legal 2/32-inch deep tires from 70 mph was a staggering 499.5-feet in 7.5 excruciating seconds."....
"The runs indicated that the average stopping distance for the 4/32-inch deep worn tires was 377.8-feet in 6.0 seconds.
Costco has a tire sales with $70 off Michelin plus $60 more if you use their CITI credit card--with a bit reaction time loss at70+, guess I am buying tires this weekend.

 

[SecondCor521]

Translation: "We care about your safety." or "We want to sell more tires."

 

[nwsteve]

Translation: "We care about your safety." or "We want to sell more tires."

No question! But given you are going to buy anyway soon, why not have a bit of extra margin of error now? I consider it a minor investment in avoiding an increase in insurance and potentially improving longevity.

 

[Telly]

Running tires down to 2/32nds leaves about no hydroplaning resistance, since the water cannot squeeze through the remaining small cross-sectional-area of the circumferential grooves fast enough. When tires get down to around 4/32nds I'm replacing them. Actually, I'm probably replacing them at 5/32nds on some, as the wear on all four tires is not the exact same, no matter how much/often they are rotated. One hydroplaning incident could mean severe debilitating injury, death, or same to others. In weighing risks, I'm more comfortable climbing ladders, working on a steeper roofs, etc., than driving with near-worn-out tires in rain. As they say, YMMV... especially if it ends with a violent bang! Not preaching here, just sharing my thoughts, and actions.

 

[SecondCor521]

I take mine into Discount Tire and have them rotated every 7K miles or so and will probably replace them when they tell me to.

I agree that there is no reason to penny pinch my way into an early dirt nap. But the cynical part of me wonders if the rule someday will become using a Kennedy half dollar to provide 6/32s, because six is better than four which is better than two.

 

[Telly]

I agree that there is no reason to penny pinch my way into an early dirt nap. But the cynical part of me wonders if the rule someday will become using a Kennedy half dollar to provide 6/32s, because six is better than four which is better than two.

Yeah, there sure is a point of diminishing returns there! Except for the tire stores, ha ha!

The old adage was to "slow down" in the rain. When I moved to Texas many decades ago, "slow down" was not in the knowledge base here... still isn't! But our climate and road drainage here can give some sudden surprises even after a rain has stopped and pretty much dried up.

 

[Bamaman]

We.have had are with ultra high performance low.profile tires, and we are tired of replacing tires.worn.out at 25k miles or less. I had to buy 2 tires last week,.and they were quite expensive.. These tires will look just fine and 2 days later will have the cord/belts showing.

My future vehicles will not have low.profile tires. I am looking for vehicles that get 40k or.more miles out of a set of tires.

 

[RetireBy90]

We.have had are with ultra high performance low.profile tires, and we are tired of replacing tires.worn.out at 25k miles or less. I had to buy 2 tires last week,.and they were quite expensive.. These tires will look just fine and 2 days later will have the cord/belts showing.

My future vehicles will not have low.profile tires. I am looking for vehicles that get 40k or.more miles out of a set of tires.

+1 on low profile tires. We have a Subaru Legacy sedan with them. DW hit a rock outcrop on side of road (it was covered in snow just as the rest of the road) about 6" high. It broke the wheel and screwed many parts of suspension and other systems. Cost over $3k to repair. My truck with normal tires runs over that rock outcrop with no damage.

 

[RunningBum]

A few years ago I tried to squeeze one more year out of my tires. They were still legal, but close. I almost made it, but in a March snowstorm I went into a skid on a downhill, only going about 10mph, and went into a ditch and hit the end of the guard rail head on. My car was totaled. Luckily there were no shards of metal in this Takata airbag because I got to experience putting my face into one.

I'll never try to get a little more out of worn tires again. Luckily, this incident only costs me money (I self-insured on collision) and there was no injury. Next time may not be so lucky.

 

[Jerry1]

I live in a state with snow. I would never let my tread depth get to a point where I actually had to measure it in order to make a decision on replacement. As has been said, you’re going to replace them at some point soon anyway, may as well go ahead. Stretch it out may save you one set of tires over the life of the car if you have standard tires and you own the car very long term.

 

[JoeWras]

Quarter? Penny? Neither.

I never let them get that low. I don't wait for wear bars. When I can start easily seeing the wear bars buried below the tread, I change.

My parents' only serious accident was due to bad tread (hydroplane). After that, my dad insisted on not letting them go too long.

 

[euro]

The other thing to keep in mind is that tires also "age" and should be replaced after 6-10 years regardless of how much tread. For example, my DW only drives 2-3k miles per year, so her tires will typically "age out" before they are worn.

 

[OldShooter]

That linked tire test in the OP was done on a wet surface. Not mentioned in the OP.

Actually, the best tread depth for dry adhesion is zero. That is why race cars use slick tires. It is also why some racing series mandate a certain amount of tread -- to slow competitors down.

As @Telly points out, the issue with tread depth is an aquaplaning issue. It is also, actually, a tread design issue. The design needs generous channels that allow water to escape so the contact patch does not aquaplane. I always select tires with this thought in mind; tread designs are done with significant consideration of consumer perception and I have seen some really stupid ones. If you live somewhere where it rains a lot or where it hardly ever rains, that should be considered when you look at your tires' tread depth.

 

[Chuckanut]

I live in an area with lots of moisture on the road due to frequent though not necessarily large amounts of precipitation. I would never let my tires get down to 2/32. It's a matter of safety. My life and health and that of my loved ones are worth the cost of an extra set of tires every few hundred thousand miles.

One accident (my fault or not) because my tires would not stop me in time would probably cost me many, many times the value of the 'extra' tread life I tossed away. Not a good risk/reward ratio, IMHO.

 

[Sunset]

A few years ago I tried to squeeze one more year out of my tires. They were still legal, but close. I almost made it, but in a March snowstorm I went into a skid on a downhill, only going about 10mph, and went into a ditch and hit the end of the guard rail head on. My car was totaled. Luckily there were no shards of metal in this Takata airbag because I got to experience putting my face into one.

I'll never try to get a little more out of worn tires again. Luckily, this incident only costs me money (I self-insured on collision) and there was no injury. Next time may not be so lucky.

+1
Once I drove in winter snow with fairly bald tires, slipping and sliding for the most part. I got new tires and was amazed at how much better my traction and turning was on snowy days.

 

[Texas Proud]

I take mine into Discount Tire and have them rotated every 7K miles or so and will probably replace them when they tell me to.

I agree that there is no reason to penny pinch my way into an early dirt nap. But the cynical part of me wonders if the rule someday will become using a Kennedy half dollar to provide 6/32s, because six is better than four which is better than two.

Problem with that is some tires start with 6/32 tread depth...

 

[Sunset]

We.have had are with ultra high performance low.profile tires, and we are tired of replacing tires.worn.out at 25k miles or less. I had to buy 2 tires last week,.and they were quite expensive.. These tires will look just fine and 2 days later will have the cord/belts showing.

My future vehicles will not have low.profile tires. I am looking for vehicles that get 40k or.more miles out of a set of tires.

I usually look for 65K or more miles.

 

[foxfirev5]

To me tires are more important than all the new crash avoidance technology. I'd much rather have my 15 year old Lexus with newer premium tires than a year old car with an 1/8th inch of tread.

 

[JoeWras]

Problem with that is some tires start with 6/32 tread depth...

Well, there are high performance tires mostly used for the track. You have enough tread to drive there and back home. This is why you hear about people with performance cars burning through really expensive tires at a high rate even if they are not constantly doing burn outs. Of course, the soft compound of the tires exacerbates the wear even more.

For most all seasons, or mere mortal tires, they start at 10/32 or 11/32.

 

[JoeWras]

To me tires are more important than all the new crash avoidance technology. I'd much rather have my 15 year old Lexus with newer premium tires than a year old car with an 1/8th inch of tread.

+1. Those small contact patches are the most important safety feature of a car. And over the last 100 years, incredible improvements have been made.

 

[jimnjana]

The other thing to keep in mind is that tires also "age" and should be replaced after 6-10 years regardless of how much tread. For example, my DW only drives 2-3k miles per year, so her tires will typically "age out" before they are worn.

Florida is tough on tires. 6 years could be pushing it.

 

[Chuckanut]

Has anybody who has bought tires from Costco brought them in for rotation? Do you need an appointment? How long did it take?

 

[SecondCor521]

Has anybody who has bought tires from Costco brought them in for rotation? Do you need an appointment? How long did it take?

A long time ago. No appointment needed. Usually took a long time - 1.5 hours.

 

[kgtest]

I run em until they start squeaking "peel out" and that is around 2/32 . Trying to stop with no rubber is a lot more dangerous...I did it once when a tire flew off...hello grinding rotor and car frame. Long walk of shame to collect the tire that flew rolling down the highway.

 

[JoeWras]

I run em until they start squeaking "peel out" and that is around 2/32 . Trying to stop with no rubber is a lot more dangerous...I did it once when a tire flew off...hello grinding rotor and car frame. Long walk of shame to collect the tire that flew rolling down the highway.

I saw that happen to a guy right in front of me on the highway at 70 mph! He had some lowrider gig, I suspect a hub broke or something.

He did a great job pulling over without panicking. However, the wheel kept going and crossed 3 lanes of oncoming traffic, after jumping the center guard wires! Thank goodness it found a seam and nobody on the other side collided or had a wreck. I don't even think the people in the oncoming side ever saw the wheel -- because you don't expect that coming at you.