NoVector

Appreciate your thoughts on the rear tire blowout I had today on the GTS. I was going about 40 when it blew and I’d guess the ambient temperature was about 85F. I see from the PO’s receipts that the tire was purchased in 2003; but you’d never know it based on the tread. I’ve never seen a tire do this on the inside, sidewall--it's almost as if the entire sidewall was tearing away from the tread. So my question is, can a tire dry-rot from the inside out? There’s no exterior evidence this tire was going, no cracks, etc. Just wondering if something else could have caused this like an overheating brake or something(?) Where the blow-out occurred and also still in the tire is the fine rubber powder—I’m not sure if that’s normal or if it is from dry rot.

BTW – first time I’ve had to use the inflatable tire. It wasn’t so bad. But that little scissor jack is another thing…. To be safe, I chocked all 3 wheels with rocks to make sure it didn’t roll.

I’m just REALLY glad I wasn’t doing 100+ when it went! It’s given me reason to pause and “think” about whether a tire is good for high speed or “know” a tire is ready for high speed.

DeWolf

You should perhaps contact Michelin about that.

SeanR

Find the DOT date code on there, and then google search to find out what month/year the tire was manufactured. 5 years is about the oldest you want to go.

Tails

Maybe two aspects here:
1. The age of the tyre (tire) anything over 7 year is suspect as the rubber detoriates.
2. The failed side wall could be from too low tire pressure causing excess flexing of the side wall.

I have seen side wall wearing as the pressure has been too low that the side wall has rubbed on the wheel flaring.

What pressure were you operating with?

Tails 1990 928S4 Auto

NoVector

Funny, but on page 2 of the warranty book that came with the tires, it says "This limited warranty only applies to the original purchaser." I see he paid $163 per tire. I guess Michelin's aren't "all that".. Replacement tires I ordered today ar Fusion ZRi's. I had them on the 84 and really liked them.

Bruce

blown 87

Looks like a classic low pressure failure to me.

Mrmerlin

a failure like that indicates the tire was run on the rim flat or close to flat.
I would bet when you remove the tire you will find an area on the other sidewall that has the flaking chipping rubber.
The age of the tire not withstanding this tire was subject to operation outside of its intended use

NoVector

Tails - Thanks, I normally keep them at 36 psi and I usually check them about once a month. Funny, but I was thinking on the way home, where the hell was the tire pressure warning light on the dash when I needed it?

IcemanG17

my guess is it sat for a LONG time.....the tire went flat & all the weight pinched down on the sidewall......still scary...

cold_beer839

+1

I used to sell tires, that failure was caused by low air pressure. You probably rode for several miles with near 0 air pressure causing the tire run on the sidewall (thus wearing the "MICHELIN" lettering, and producing the black powder inside the tire). The heat built up to extreme levels then blow off the thread and sidewall.

Those look like Pilot Sport 1 All Season tires, Michelin hasn't made those in a while, but you should be able to find a new one on eBay or Craigslist. Frankly, I replace those old tires anyway, that way you know whats under you.

jcorenman

Bruce,

A couple of thoughts: Purchased in 2003 means the tire is at least 7 years old, but it could have been sitting around for quite a while before that-- as mentioned, check the DOT date-code. There is no max age spec in the US, but the European spec is 6 years max from date of manufacture.

In your first picture there is a "M+S" designation after the size-- this usually means "Mud+Snow" (i.e. a winter-rated tire) although the tread doesn't particularly look like a snow tire. But depending on exactly what it is, it may not be happy with Texas summer heat.

Also, I bet the history has some bearing on the failure-- as Brian said, maybe sitting flat. Also, tires that sit rot faster than tires that are used-- something about lubricants in the rubber not getting redistributed when the tire sits.

Congrats on no damaging anything else! We had a rear on our S4 blow a few years ago on a freeway ramp, a high-speed left-hand sweeper, because of under-inflation caused by a nail. A bit exciting for a moment, but all was OK. And ditto on jack, and spare.

NoVector

Thanks everyone! This has definitely been a learning experience for me. So the consensous is, the tire went low, and then turned to crap--and any tire 6+ years old should probably not be trusted. Certainly not at high speeds. I did look at the inside sidewall on the passenger side just now--coincidently, it doesn't look so good either. Maybe the tire shine stuff on the outside sidewall is deceiving too...

Although I am wondering why I never saw the RDK light up... just another one of life's mysteries I guess.

Thanks again everyone. The new Fusions will be here this week and I'll soon be on the road again--and have piece of mind! / Bruce

Tails

Bruce,
My RDK requires 43psi on the rear tyres.

You may need to check and reset your RDK pressure sensors. This procedure is fully described in the WSM and also in the Owner Manual IIRC and there is a short setup procedure and a longer set up procedure.

36psi is a little low, check you Technical Specification Booklet.

If you are carrying out spirited driving with 36psi then you will get excessive side wall distortion and flexing, that can cause failure over time.

Tails 1990 928 S4 auto

Tails

Stromius

Bruce why not call it in anyway and see what you get for your troubles?

danglerb

+1 on checking the DOT date code stamped into the sidewall (only thing usually that isn't raised, its an oval with stamped in digits).

My guess is that maybe sometime in the past the tire was run flat, maybe fixed for leaks, but still damaged.