is 4/32 to 5/32 tread safe on snow and ice?

[Russell]

I recently had an accident where the rear of my car slipped in packed snow and perhaps some ice. No other cars seemed to have problems. my tread is mostly 5/32nd. The right rear was closer to 4/32nds. I think they were too thin for winter use. I pushed them too long. Opinions?

Tires are 225x60x15 Bridgestone Turanza LS-H with 63,000 miles and about 5 years old.

 

[crj19]

Buy some new tires.

 

[mrsilv04]

No. Time for some new rubber. 63,000 miles is plenty good enough.

 

[Russell]

To all. New tires will be put on after car is out of body shop next week. Will put on michelin Exalto A/S tires.

Even the basic question of safe tread depth/age still needs to be answered. Feds consider 2/32 as THE safe limit. Following that logic my tires would be safe. A Tirerack study seems to suggest that 4/32 is the real limit for real world situations.

Age of tire with flexibility/stiffness issues may come to play as well.

 

[CapriRacer]

Russell,

Here's the fundamental problem:

Is there a break point or discontinuity in the traction curve so that we could - from that point on - say: "This is "unsafe"".

Nope, there isn't.

So how do we define what is "safe"?

NHTSA abritrarily selected 2/32nds of an inch back in 1968 as the "legal limit" - and it has become "Industry Standard".

There is increasing evidence that decreasing tread depth results in decreasing traction - and obviously worse is worse, but where do you draw the line? How do you define "unsafe"?

Some folks - in order to be helpful - have stated that tires should be removed when they reach 4/32nds for all seasons, 3/32nds for summer, and 5/32nds for winter - but again - it is an arbitrary point.

 

[Russell]

Excellent helpful answer

 

[GMGuy]

Exactly. The "standard" is only a legal measure, and has no bearing on performance.
Lots of thread is best for snow as it will allow the tire to "grab" hold of the snow. Reduce the thread depth and the ability to "grab" is greatly reduced.

Take a walk down a sloped snowy/icy driveway with a well threaded boot.
Make the same walk with sneakers.
Dare to dry your sunday shoes? =-)

Alex.

 

[Titan]

Great answer, CapriR!

Let me add another: NO. There are no "safe" tread depths on snow and ice. You need to understand that unless you have studs in your treads, you are at the mercy of a very small window of inertia and traction no matter what the depth of the treads.

Exaltos are fine tires (I even have one on the rear of a motorcycle), but, they aren't able to supercede the laws of physics...so, you had best be VERY careful on snow/ice, no matter what tires/tread depths you have.

 

[eljefino]

It bugs me a bit that all season tires are getting thrown out at 5/32" tread, when new they're only 11/32".

Seems like if one ran winter tires (often 15/32" when new) they could more properly finish off their 3-season tires. Maybe they'd have to slow in the rain near the end.

It's rarely brought up that the sipes on all season tires, that help them in snow, are often only cut halfway into the tread, as a wear/traction compromise.

One is always wearing out some sort of rubber, may as well be appropriate for the weather conditions they're in.

Finishing off the all season tire helps reduce tire disposal, a PITA.

If these 225s were on the BMW in your sig, I can understand there being issues... their width will make them float on the snow more, instead of digging down to pavement.

 

[Russell]

Very true. However, really do not want to have two complete sets of tires. Most tire dealers will not sell winter tires unless a set of four, unless a replacement.

Also, the 225s on my car are a standard oe size. They have worked well in last year's snow conditions. Just worn out IMO.

In the future, when the weather looks icy, I can and will stay at home. As you are aware, Ky has few really bad days.

 

[Drew99GT]

Originally Posted By: eljefino


It's rarely brought up that the sipes on all season tires, that help them in snow, are often only cut halfway into the tread, as a wear/traction compromise.



That is a big factor! I now look for tires with full depth siping and lots of it. Seems that BFGs have the sipes all the way through the tread block - like on the Traction T/As.

 

[Russell]

Originally Posted By: Drew99GT
Originally Posted By: eljefino


It's rarely brought up that the sipes on all season tires, that help them in snow, are often only cut halfway into the tread, as a wear/traction compromise.



That is a big factor! I now look for tires with full depth siping and lots of it. Seems that BFGs have the sipes all the way through the tread block - like on the Traction T/As.


Really good points I may need to reconsider my tire choice. Couple of questions.
Which BFGs have full depth siping?
Is there a downside to it?
Any other tires with full depth sipping?

 

[Drew99GT]

The Precept Tourings have it; the Traction T/As as well. When you're looking at tires, take a small flathead screwdriver with you and jam it into a sipe - see if it goes all the way down - the same length as the tread block. I'm sure other manufacturers are the same. I know the Michelin Destiny's go all the way. It's hard to tell by looking - that's why I use the screwdriver technique.

On many cheaper tires, the only go in half way, so when you're at, say 6/32s, there will be hardly any/if any siping left!

 

[rjundi]

IMHO is really depends the tire your using and its winter capabilities. Some tires with full tread are still useless on snow/ice.

You were going to fast for the conditions(known or unknown) and an accident happened. I would not read much further into it.

 

[jmacmaster]

"Feds consider 2/32 as THE safe limit."

That is truely absurd. That is 1/16 of an inch. Look at that on a ruler and tell me that you think that its adequate tread. And, anyone who trusts what the feds say about anything needs to have their head examined. 5/32 is the most recommended depth for tire replacement. Personally, I would not run tires on snow that are(5/32) that bare. And I've driven on snow since 1959. 2/32 tires are baldies; I wouldn't even run them in the summer.

 

[Russell]

Originally Posted By: rjundi
IMHO is really depends the tire your using and its winter capabilities. Some tires with full tread are still useless on snow/ice.

You were going to fast for the conditions(known or unknown) and an accident happened. I would not read much further into it.


Perhaps. However, I was going 30 mph and passed by a suv going about 60, Immediatly, the rear end started slipping out and the entire car started going into the other lane of heavy traffic. Got it under control enough get it of the road into a ditch at about 15-20 mph. I saw no other cars with as much trouble as me.

BTW, TireRack says 6/32s for snow and 4/42s for rain are safe limits. Of course, they want to sell tires.

 

[AHC]

Consumer reports says that performance deteriorates at around 5/32nds.

“Unfortunately, 2/32 of an inch may be too late if you drive in rain or snow. Based on our tests of new and half-tread-depth tires, you may want to consider replacing the ones on your car or truck closer to the 5/32-inch groove depth that marks the half-tread point on many tires.”

 

[1sttruck]

Use A/S tires to save money if you wish, but winter tires will usually work better in winter conditions. Chains are cheaper than winter tires and work well with a known set of tradeoffs. That's just one of those 'how things work'.

 

[Russell]

Originally Posted By: AHC
Consumer reports says that performance deteriorates at around 5/32nds.

“Unfortunately, 2/32 of an inch may be too late if you drive in rain or snow. Based on our tests of new and half-tread-depth tires, you may want to consider replacing the ones on your car or truck closer to the 5/32-inch groove depth that marks the half-tread point on many tires.”


I agree if you are going into the winter with rain/snow and ice. Not so sure if you are just going into summer with 5/32s left. They have a little life left. Unfortunatly, I did the opposite. Never again.

BTW, I repaced my wife's tires on her Explorer with Michelins because they were over 5 years old yet had sidewall cracking and plenty of tread because I wanted her to be safe as possible. I thought I was fine with my car. Wrong!

 

[PT1]

I replace tires at 4/32. Which I figure is giving away the last 10% of tire life. Since the average price I pay for tires is $110 each that is $11 per tire or $44. My insurance deductable is $1000 which means one accident caused by too little tread depth is equal to replacing 6 sets of tires 10% early. Not to mention the higher insurance rates, potential injury, litigation, etc, etc.