[PackPride85]

Curious what the odds are of getting a flat at the track and whether its OK to run a patched tire? I'm looking at getting a dedicated set of track wheels for next season and debating whether the replacement certs for discount tire are worth getting for track tires. The certs are good for 3 years and don't exclude track used tires from what I can tell.

[wjones14]

Patched tires are generally considered safe for normal driving and highway use. But common sense should tell you a patched tire isn't the best idea on a race track, where you're pushing the tires MUCH harder than in ordinary driving. We've all seen what happens when a NASCAR tire starts going down - the car usually ends up hitting the wall.

[Maynard]

Not recommended to run repaired tires on track - the added heat and stress is more than typical street use, and could cause failures. If you do patch one, be sure it is a true tire-off job, with an inner patch, not just a tire plug covered in glue. I don't hear about a lot of tire failures on track at the HPDE's I attend, and I think a lot depends on how aggressive you are with the gators.

[Fabb]

Depends on how hard you drive your car on track. If driving 10/10, def new tire. If newbie driving 5/10, you can run patched. I've run patched/plugged tires at track before, just apply common sense and not run over sausage curb

[medphysdave]

I recently ran a properly patched cup2 tire on track. It was in the center of the tire. I didn't run the tires down to the cords. I'm still learning so I'm certain I wasn't as hard on them as someone with more experience would be. I likely would not have done if it had not been very central in the tread.

[Suds]

I would not run a patched tire on the track!
I see +180F temps on my tpms while tracking my cars.
I have seen some bad things happen when tires loose pressure on the track.
A new tire is cheap compared to fixing your car or fixing your body after a crash.

[medphysdave]

I saw plus 180F on the repaired tire with my track connect sensors. Until someone can show some data on a patch/plug failing due to temp, adhesive, or something else it's all speculation. I'd like to hear how these fail. The detailed physics. I haven't been able to uncover anything in my research beyond "a tire is cheaper than your car or life.".

[PackPride85]

Originally Posted by medphysdave

I saw plus 180F on the repaired tire with my track connect sensors. Until someone can show some data on a patch/plug failing due to temp, adhesive, or something else it's all speculation. I'd like to hear how these fail. The detailed physics. I haven't been able to uncover anything in my research beyond "a tire is cheaper than your car or life.".

From what I've been reading it can be hit or miss depending on the tire and type of patch and failure. Tire rack has some good info here:

https://m.tirerack.com/tires/tiretec...jsp?techid=225

Some tire mfgs will still support the original speed rating of the tire with a patch if it meets certain criteria. Some do not, meaning that tire is no longer rated to max speed. Hard to tell if that's a pure liability decision between each mfg or if compound related.

[ZL9M2]

In 30 years I've never seen someone pick up debris to the point of getting a flat with a dedicated track wheel/tire set, if that's what you're asking. Also, I know nothing about physics, but do know that a non-patched tire is better than a patched tire and don't want to be the first one to find out when/how a patched tire might fail at the track.

[medphysdave]

I don't think there is any debate on which is better between patched vs unpatched. I'd like to see evidence of how a proper plug/patch fails.

Perspective. Let's say we have a 0.25" hole. Properly repaired from the inside the rubber plug component is ~ .25" and is bonded/backed by a roughly 2" diameter patch. Adhesive is used to glue this into place.

Let's assume the plug separated from the patch. How is a glued in 2" patch going to fail? It would have to melt and or fail from pressure trying to force it through the original hole. This assumes no plug is left, tread didn't melt into hole, etc etc.

I'm not trying to convince anyone to run repaired tires. That's a personal decision. My opinion is that liability drives all the responses. Manufacturers aren't going to stand behind it. And anyone providing opinion doesn't want to be on the wrong side of a tire failure.

I ultimately made my decision on the lack of info supporting failures for repaired tires and the whether I was going to be running the tires at or beyond their limits.

[pal]

I'd say the decision on running a tire with a puncture repair should be made on a case by case basis and not using generic advice or consensus on the interwebs. Multiple factors can be at play, and not just the physics of the repair itself. For example, did the car drive on a flat or almost flat tire and possibly also weaken/damage the sidewall?

That being said, in the 21 years of doing HPDEs, I've only had 2 tire issues. One time I got a nail in the tire - never quite figured out if it was in the paddock or on track but I discovered it on track when the rear end started to get squirrelly on a couple of corners and on the third corner I couldn't make it so went straight off. Shop applied a patch plug from the inside and I did a couple more sessions and called it because I wasn't comfortable with the potential weakened sidewall since I had put side load on that tire before going off and while it was low on air. The second time was when I went off track at a decent speed and the front tires got a little sideways action in the grass and dirt, embedding enough of small rocks and grass in the space between the bead and the rim. Didn't lose pressure, but when I brought it to a tire shop they noticed some bead damage. They repaired it enough for me to get home but not subject the car to track loads.

Bottom line, in the right situation, I'm not too concerned with a properly applied patch plug repair. But I will always make a decision on a case by case basis.

[medphysdave]

Well said

[M2joey]

Yes, a plug kit is your "secret" friend at the track. I have had a few punchers over the years. One on a 5-mile old RE-71R, plugged and ran the tire to a slick. Once had picked up a screw exiting the pit. I could hear the screw hitting the ground right away. Plugged that tire as well and ran until there was no tread remaining.

In short, this may not the best practice or something that the club you are driving with will approve of. However, plugs work great for "typical" tire punctures.