ZO6Pilot

I am signed up for a HPDE in novice class at Summit Point in a couple weeks. While my car was up on a lift today, the mechanic pointed out two nails in my left rear tire (the Goodyear F1). I was surprised as I have not had to fill the tire, and it is apparently not leaking.

The mechanic suggested just leaving the nails in until the tire begins to show signs of leaking. Alternatively, he said it could be hot patched from the inside, but not plugged. However, I began to wonder how safe either of these options are given I will be exceeding 100MPH on the track.

I am thinking of getting two new rear tires for the HPDE, and keeping the two current rear tires for use at a later date. Am I over-reacting to worries about driving on this tire at a HPDE? Any experienced advice would be appreciated. Thanks.

Doc

emf

<ahem> DO NOT RUN IN ANY HIGH SPEED EVENTS WITH NAILS IN ANY TIRE.

I'm not surprised that everything stayed put at highway speeds, but between air pressure and speeds that you'll see during a DE, it could easily pop loose. The LAST thing you need is to learn how to drive on a cut or leaking tire . . . it's no fun, and typically ends badly.

Could the tires work for your event? Maybe . . . but on the flip side, why chance it?

*edit* On the patch versus new debate, that's completely up to you -- properly patched, there shouldn't be an issue with running on a patched tire. Standard caveats exist, the location of the puncture / patch will ultimately tell you how safe the repair will be.

ZO6Pilot

Thanks. That's pretty much how I saw it concerning leaving the nails in. However, I am not sure I understood your opinion about running a high speed event on a patched tire. I would not think twice about it under normal driving conditions, but the thought of blowing a tire at 100+ scares me a bit. I suspect a patched nail hole would not cause a blow out, but even a quick leak might be a problem. I'd value the opinion of you or any other track-experienced person on whether I should just spring for a couple new rear tires. (Or would one tire be sufficient, even though it is being matched with a companion with only half the tread left). Thanks.

Doc

StArrow68

I think you have answered it for yourself. I've run on a patch once and for peace of mind I'd go with replacements and save the patched tire for when you want to either sell the car or just spend more time on the roads and not the track.

You note that you are in the novice class and it takes more than a few days to get up to real speed, you won't believe how much faster you will be after several events, but why give yourself anything else to be a concern? Have a great time!
Randy

emf

Short version, if patched properly the overall structure of the tire is sound -- the puncture itself is sealed, and then patched with an additional amount of rubber which basically means that the patched area is thick enough to support the air pressure and not allow the previously punctured area to leak. Essentially, it's all rubber, and is not necessarially prone to blowout or failure any moreso than an average street tire. The stress applied to the patched side of the leak, is purely heat and pressure, which is why I stress a "proper" patch should be OK.


How close are the punctures to each other? How close are the punctures to the sidewalls? Is the mechanic sure that they're nails?
Stuff like this will ultimately tell you if you can safely run with patched tires, and if they will be able to properly bond the patch to the tire over the puncture.


New tires ultimately *will* be the safest option [in comparison], assuming that you're able to scrub in the new tires before heading to the track. Personally, I'd head to an event with fresh rubber, but I'm a bad barometer . . . . . I typically end up rotating through slicks fairly often.

Skant

One of the guys I knew was racing on his Khumo Victoracers with 7 patches in one of the tires.

- Skant

AU N EGL

This guy must have a very very close relationship with GOD.

One never really knows if the punture cut a cord or not and how well it was patched. If a cord or cords are cut that tire will give way without notice. Most cases the tire FEELS out of round. We have seen this happen many times.

I agree with emf. If the tire is patched properly, you will be fine. But new tires or scrubs and unpatched tires are safer.

New treaded tires really should not be used for HPDEs. The rubber has not aged and slidding around corners can cause blistering. Highly warn street tires, down to the wear bars, are the better street tires to use.

Good luck

freefall

I agree with them. I've found that nails will wear the heads off and not leak air when in the main contact patch of the tire. After visiting my construction site a few times I've managed to pick up a couple of nails that I need to get patched this week...

ZO6Pilot

Thanks to all. I just bought a couple Nitto 555R2 305/35-18 tires for track day, and will patch my OEM tires for use later.

Doc

StArrow68

Just FYI, I ran GY Supercars for two sets before switching over to Kumho's. But, I put the rear Kumho's on first and ran a two day event with the mixed set. Let's just say they didn't have the same grip and it was a fairly slow weekend. It does provide some lessons in car control, so not all was lost, let's just say interesting. FWIW
Randy

AU N EGL

Randy you had fun didn't you?? and that is what its about.

Something about a bad day fishing is better then a good day at work . . . .

StArrow68

Absolutely enjoyed it, was also a wet Sunday morning and got to slide at lower speed some, very fun. But when up to temp and dry it is a different feel, something I wouldn't try to do on purpose again. And yes, any day on track is better than almost all other alternatives. Just surprised at how few actually are willing to try it out. If they only knew!
Randy