Tire failure (debris induced) during track day: no drama

[willyjp]

This morning I was doing a dealer (Audi & Porsche) sponsored track day @ PIR (Portland Intl. Raceway). It was put on by a driving school/track day organizer @ PIR and was focused on "first timers", but more track-experienced Porsche and Audi owners were invited as well.

Track sessions were with a ride along instructor to start, with lapping later if they "signed you off." The warm up was a fairly fast autocross course in the large paved paddock area where the pro-teams set up their pits for Indy Car, NASCAR and GP bike events which run there.

After some good, hard autocrossing, with an instructor still onboard, I was accelerating down the pit straight on my third lap, doing about 115 mph in 4th, when we heard a loud "bang" from the L Rear wheel well. Driving I felt nothing else, no vibration or anything. My instructor immediately shouted, "Did you hit something?", to which I replied, "Didn't see anything on the track." He than said, "Do you have any warning lights?", to which I replied (correctly at that moment), "No." About 1 second later my TPMS light went on!!

I slowed, still feeling the car acting just fine, and rolled into the apex area of the chicane at the end of the pit straight. As I slowed below about 40 mph I began to feel and hear the "thump, thump" of a flat tire!

After verifying that it was indeed a flat L Rear, still on the rim, I slowly drove around a crash barrier and into a secure off track area. The Audi dealer's R8 Tech was there in about 30 minutes (had to come across town) with a spare "loaner" 11x19 wheel with a used but sound PZero tire mounted.

One interesting aside was that the car was so low that the Audi Tech couldn't get the R8 jack (which he brought) or any other jack under the car on the flat side!! Fortunately, the service road we were on had about a 2" drop off to grass to the right side, and after I drove the right wheels off the edge, the Tech could get the Audi jack under in the middle on the left and get the car off the ground.

Before that, I'm not sure any racing jack could have slid under on the affected side. The Tech had one and it was too thick! He tried the inflation pump, but it wouldn't hold air at all (no surprise after we saw the hole). Don't know what we could have done if we couldn't jack it! Anyone else had this problem?

Once off, the 305 PZero displayed a clean hole through the tread surface, with shredded fabric plies visible in the depths. The hole was about the size of an M16 round (5.56mm) so about 0.2 to 0.3". Around the hole, clearly visible in the tread of the tire was a hexagonal dent or impression. So, apparently I had a hex-headed screw or bolt of about 1/4" size that had imbedded there and punctured the tire.

Most likely got in during autocrossing on the paddock area. Probably was so firmly seated that it took a couple of fairly fast laps to throw it out into the wheel well (the "bang") and let the tire go flat.

We saw the track sweeping machines at work when we arrived that morning, but likely they didn't sweep the paddock area, maybe because the rather elaborate autocross course was there @ 07:00, so obviously must have been set up the day before.

My tires had 5/32" left all around and the dealer's R8 Tech says they advise replacement at 3/32". Clearly, the L Rear is ruined, so ordered a new set of Michelin PSS's all round, which will take a couple of days to get.

Interesting that Audi had PSS's in 235's and 295's in their supply chain but "don't stock"--per the R8 Tech--305's in the new Mich. PSS. But they were able to snag me a pair from "another source," which will take "3 or 4 business days".

So, no moral, no weighty conclusions drawn, just an anecdote about something that can, and does happen on any road any day. But the nice thing was that I had a tire fail @ 115 mph and, except for the TPMS warning, it took a good 5 or 6 seconds to even be aware of it!

Also, the car was absolutely glorious before the flat tire, and I'm sorry that I didn't get the chance to get "in the groove" and really let it out. I've driven this car pretty fast in some pretty difficult road and weather conditions (and on 2 previous track days) and I have yet to feel that it was anything but absolutely unflappable, and ready to go as fast as I care to go! Looking forward to it feeling even better with the new PSS's.

PS: another interesting aside: my instructor was a Viper guy, and I think my breaking was scaring him! He kept yelling for me to "brake", when I was shutting off conservatively for the R8 on this track (have driven it before). Using his braking points, I only had to brake at about 1/2 the R8's negative G capability! Vipers must not stop very well!! Other than that, I liked him. He made some very constructive suggestions about my line on this track.

[harrison]

You can drive the damaged tire onto a block, of some sort, thus giving the clearance neccessary... for the jack to fit under the car. So glad you had a great track day,even with the mis-hap.

[willyjp]

You can drive the damaged tire onto a block, of some sort, thus giving the clearance neccessary... for the jack to fit under the car. So glad you had a great track day,even with the mis-hap.

Great & obvious suggestion! The Audi Tech was rummaging around looking for "a block" in their service car (great little Q5 all outfitted with tool boxes in the back...Tech said Audi puts them together and sell them to dealers...in fact REQUIRES dealers to have one of they are a "Premium A8 Dealer.")

Now I know why he was looking for "a block." I think maybe an R8 ought to carry one? The assistant Tech who came with him suggested...even started to try...lifting on the wheel arch of the fender!! R8 Tech said he didn't think that was a good idea!!

[desperado]

You could try using the tire slime bottle as your block - that's probably all its good for. Fortunate the tire did not come apart at those speeds, as it would have done quite a bit of damage to your fender.

[Laurie]

Glad to hear there was no damage. I also had a track day tire issue this weekend, my front left tire started coming apart. But I had a lot of vibration on the straight, so I was able to catch it before it blew. I was wanting to get rid of those pzeroes for some PSS's anyway.

[KfabR8]

You two will LOVE the new Super Sports - great rubber indeed!

Good to hear it all came out good for you Willy. Love the Viper guy saying brake! They just don't get how well the R8 stops, do they?

[mngolfer]

When I would go to the track I carried two 2X10s about three feet long for just this reason. When I purchased the puck from Rob Microy I don't need the ramps any longer.

[willyjp]

When I would go to the track I carried two 2X10s about three feet long for just this reason. When I purchased the puck from Rob Microy I don't need the ramps any longer.

not sure how the puck works for that? thought it was just for the jack--car interface?

if the tire is flat, wouldn't you ideally need a block or board long enough to bridge from rim to rim (11"+) to get the rim (and the rocker panel) to elevate high enough to get jack under the car....without putting all the weight of that corner on just the outside rim? I guess you could just have the block under the outer rim long enough to get the jack started?

I don't have a puck, but I thought they were 3" or 4" in size? I know they've got a handle like rib on the backside....do you roll up on that? on one rim?

[harrison]

Using the puck on the jack actually requires the car to be even HIGHER.

[mngolfer]

This is what I used to lift Deperado's car to change the right rear wheel. Nothing else would fit under the car to the DEEP lift points. I put the puck in first and slid the racing floor jack under the puck. Pumped it up and we were able to remove and replace the wheel with an inflated rear tire. They were then were able to load into Desperado's Toter-home.