Nail in middle of tire tread
07-17-2015, 11:46 AM
#16
Rennlist Member
In 2002 when I was instructing for the AMG Mercedes Driving Experience, they had a Michelin Tire Engineer from the factory in the pits along with assorted Mercedes mechanics to keep this high profile event running. I had the opportunity to talk with him at length about punctures and the science behind it all during the lunch break and here's what he had to say:
* If you decide to repair a tire be aware that it loses its speed rating. It is no longer a safe tire to run hard and hot and is subject to failure. While this may not be a factor on a 20-year-old pickup truck that makes runs to Home Depot and back, it will be on a high performance car that is driven aggressively
* Modern tires are steel belted radials, and any puncture and repair breaks that steel belt and allows water to gain entry into that area. Once water gets in - and it will - the steel belt will rust and can fail, usually as a blow-out.
* All repairs should be considered temporary until you can get the tire replaced.
I do not repair my tires on my performance cars or motorcycles, or my wife's SUV. I replace them. I will use internal plugs on my garden tractor or rear duallies on my truck (but not the front tires). To me, its not worth it to take a chance on failure. I know there are those that think its OK, and if you're good with it - that's cool. But please, never take a repaired tire and run a track event on it, the loads on the tires are huge and your chance of catastrophic failure increase significantly.
Before I get in a car to instruct at a DE school, I have two questions for the student. 1) Are you running dustless aftermarket brake pads, and 2) Are there any repaired tires on the car? If they are, than I won't ride with them - I consider it too hazardous for my personal safety.
* If you decide to repair a tire be aware that it loses its speed rating. It is no longer a safe tire to run hard and hot and is subject to failure. While this may not be a factor on a 20-year-old pickup truck that makes runs to Home Depot and back, it will be on a high performance car that is driven aggressively
* Modern tires are steel belted radials, and any puncture and repair breaks that steel belt and allows water to gain entry into that area. Once water gets in - and it will - the steel belt will rust and can fail, usually as a blow-out.
* All repairs should be considered temporary until you can get the tire replaced.
I do not repair my tires on my performance cars or motorcycles, or my wife's SUV. I replace them. I will use internal plugs on my garden tractor or rear duallies on my truck (but not the front tires). To me, its not worth it to take a chance on failure. I know there are those that think its OK, and if you're good with it - that's cool. But please, never take a repaired tire and run a track event on it, the loads on the tires are huge and your chance of catastrophic failure increase significantly.
Before I get in a car to instruct at a DE school, I have two questions for the student. 1) Are you running dustless aftermarket brake pads, and 2) Are there any repaired tires on the car? If they are, than I won't ride with them - I consider it too hazardous for my personal safety.
07-17-2015, 04:05 PM
#17
In 2002 when I was instructing for the AMG Mercedes Driving Experience, they had a Michelin Tire Engineer from the factory in the pits along with assorted Mercedes mechanics to keep this high profile event running. I had the opportunity to talk with him at length about punctures and the science behind it all during the lunch break and here's what he had to say:
* If you decide to repair a tire be aware that it loses its speed rating. It is no longer a safe tire to run hard and hot and is subject to failure. While this may not be a factor on a 20-year-old pickup truck that makes runs to Home Depot and back, it will be on a high performance car that is driven aggressively
* Modern tires are steel belted radials, and any puncture and repair breaks that steel belt and allows water to gain entry into that area. Once water gets in - and it will - the steel belt will rust and can fail, usually as a blow-out.
* All repairs should be considered temporary until you can get the tire replaced.
I do not repair my tires on my performance cars or motorcycles, or my wife's SUV. I replace them. I will use internal plugs on my garden tractor or rear duallies on my truck (but not the front tires). To me, its not worth it to take a chance on failure. I know there are those that think its OK, and if you're good with it - that's cool. But please, never take a repaired tire and run a track event on it, the loads on the tires are huge and your chance of catastrophic failure increase significantly.
Before I get in a car to instruct at a DE school, I have two questions for the student. 1) Are you running dustless aftermarket brake pads, and 2) Are there any repaired tires on the car? If they are, than I won't ride with them - I consider it too hazardous for my personal safety.
* If you decide to repair a tire be aware that it loses its speed rating. It is no longer a safe tire to run hard and hot and is subject to failure. While this may not be a factor on a 20-year-old pickup truck that makes runs to Home Depot and back, it will be on a high performance car that is driven aggressively
* Modern tires are steel belted radials, and any puncture and repair breaks that steel belt and allows water to gain entry into that area. Once water gets in - and it will - the steel belt will rust and can fail, usually as a blow-out.
* All repairs should be considered temporary until you can get the tire replaced.
I do not repair my tires on my performance cars or motorcycles, or my wife's SUV. I replace them. I will use internal plugs on my garden tractor or rear duallies on my truck (but not the front tires). To me, its not worth it to take a chance on failure. I know there are those that think its OK, and if you're good with it - that's cool. But please, never take a repaired tire and run a track event on it, the loads on the tires are huge and your chance of catastrophic failure increase significantly.
Before I get in a car to instruct at a DE school, I have two questions for the student. 1) Are you running dustless aftermarket brake pads, and 2) Are there any repaired tires on the car? If they are, than I won't ride with them - I consider it too hazardous for my personal safety.
My 2 cents...
NEVER plug a sidewall.
I carry a plug kit with me just in case of emergency repair to the tread area but the tire needs to be replaced. Steel belted radials must have the hole reamed out to get the plug inserted. The severed steel threads can still wear away at the plug.
A patch placed on the inside of the tire is considered acceptable in some circles. Those circles don't usually contain high performance cars.
Good Luck
07-17-2015, 07:29 PM
#18
Rennlist Member
In 2002 when I was instructing for the AMG Mercedes Driving Experience, they had a Michelin Tire Engineer from the factory in the pits along with assorted Mercedes mechanics to keep this high profile event running. I had the opportunity to talk with him at length about punctures and the science behind it all during the lunch break and here's what he had to say:
* If you decide to repair a tire be aware that it loses its speed rating. It is no longer a safe tire to run hard and hot and is subject to failure. While this may not be a factor on a 20-year-old pickup truck that makes runs to Home Depot and back, it will be on a high performance car that is driven aggressively
* Modern tires are steel belted radials, and any puncture and repair breaks that steel belt and allows water to gain entry into that area. Once water gets in - and it will - the steel belt will rust and can fail, usually as a blow-out.
* All repairs should be considered temporary until you can get the tire replaced.
* If you decide to repair a tire be aware that it loses its speed rating. It is no longer a safe tire to run hard and hot and is subject to failure. While this may not be a factor on a 20-year-old pickup truck that makes runs to Home Depot and back, it will be on a high performance car that is driven aggressively
* Modern tires are steel belted radials, and any puncture and repair breaks that steel belt and allows water to gain entry into that area. Once water gets in - and it will - the steel belt will rust and can fail, usually as a blow-out.
* All repairs should be considered temporary until you can get the tire replaced.
Before I get in a car to instruct at a DE school, I have two questions for the student. 1) Are you running dustless aftermarket brake pads, and 2) Are there any repaired tires on the car? If they are, than I won't ride with them - I consider it too hazardous for my personal safety.
The result was... *crickets.*
Any updates?
07-18-2015, 10:47 AM
#20
Race Car
I had about 10k miles on an OEM Pirelli that had a plug and interior patch due to a nail well away from the sidewall. Never a problem with the repair, which was done by a local shop that is a primary source of tires for racers and PCA trackers. But, note well- they would never repair anything that had a puncture near a sidewall, or with a damaged a steel belt.
07-18-2015, 11:10 AM
#21
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That is where wheel/tire insurance through the P Dealer can be a good thing. With a plan like that you get a replacement tire for a repairable tread puncture. With a Road Hazard Warranty, like the one through Tire Rack, you only get a repair. You only get a replacement tire if it is not repairable, and even then you do not qualify for Tire Rack's RH Warranty if the retail cost of the tire is over $410. I don't know the retail cost of the P-Zeros on our 911s, but it would not surprise me at all if they were more than that.
07-18-2015, 11:28 AM
#22
Race Director
Nail in middle of tire tread
I saw these for sale on another forum. On a set of HRE wheels for a 991. Scary
On the inside face of the rear sidewall you don't see, but very dangerous indeed. That's where they wear down the most.
On the inside face of the rear sidewall you don't see, but very dangerous indeed. That's where they wear down the most.
Last edited by STG; 07-18-2015 at 12:00 PM.
07-18-2015, 12:42 PM
#23
I had about 10k miles on an OEM Pirelli that had a plug and interior patch due to a nail well away from the sidewall. Never a problem with the repair, which was done by a local shop that is a primary source of tires for racers and PCA trackers. But, note well- they would never repair anything that had a puncture near a sidewall, or with a damaged a steel belt.
I certainly wouldn't have a problem with a tire being plugged when the damage was no where near the sidewall, but I could understand the reluctance of a tire shop being reluctant to undertake such a repair on a high performance car, given the litigious society in which we live. I also can understand the reluctance of an instructor to drive a car at its limits on a track when a tire has ben plugged. When the only thing separating someone from an accident and potential serious injury are the quality of the tires, it's prudent to err on the side of caution.
07-18-2015, 12:59 PM
#24
I have been buying my tires from Discount Tire for the last 15 years and buy the RH policy...they replace the tire regardless of age in full.... I have out of lets say probably 20 sets of 4 tires I have had probably 3 full sets free over the years from nails etc in Chicago with construction and just crap roads. And a few tires were pretty much almost worn out. A winter snow tire was shipped for free to me in FL on vacation during xmas to where I was staying since there was no DT store nearby but I at least had the tire to get it mounted on the car. DT really doesn't like to fix high performance summer tires either but they will, however with the RH warranty they have they just give me a new tire anyway. Personally I would not go on the track with my 100K+ cars to find out if its a good idea or not.
07-18-2015, 01:23 PM
#25
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That is a nice policy that Discount Tire has. I read about it on their website. Do you know how much they charge for this per tire, as it is a an extra cost option? Good thing to have. Really, then, the only difference between that and the Porsche wheel/tire insurance plans is the wheel coverage in the Porsche plan.
07-18-2015, 02:37 PM
#26
I have been buying my tires from Discount Tire for the last 15 years and buy the RH policy...they replace the tire regardless of age in full.... I have out of lets say probably 20 sets of 4 tires I have had probably 3 full sets free over the years from nails etc in Chicago with construction and just crap roads. And a few tires were pretty much almost worn out. A winter snow tire was shipped for free to me in FL on vacation during xmas to where I was staying since there was no DT store nearby but I at least had the tire to get it mounted on the car. DT really doesn't like to fix high performance summer tires either but they will, however with the RH warranty they have they just give me a new tire anyway. Personally I would not go on the track with my 100K+ cars to find out if its a good idea or not.
07-18-2015, 03:45 PM
#27
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Zero issues over the years. My last wheel scratched was actually by they dealer on my RS7 changing out a tire that had a chunk out of the side of it I think from delivery. Anyway the stores that were near me in the Chicago area did very good work with no problems and I went to several of them. I have only put a tire on a spare here so far in Florida but I tend to find they train guys very well and use the right tools and motions not to mess up things.
07-18-2015, 05:14 PM
#28
You are also right about the crickets. I've had quite a few tires patched over the years. One on the back of my 911 was patched twice. Plus a few that were plugged. Plus I never follow the tread wear replacement guidelines. These are fine for people who sell tires, people who don't know how to evaluate tire performance, and people who write tickets. I am none of those so I replace them when they need replacing. Yet for all that I've never had a "catastrophic failure" - or even any indication of any sort of failure at all being even remotely imminent.
And I know, because I make a pest of myself, bugging the tire guys until they let me watch/supervise them the whole time, including carefully inspecting the tires both coming off and going on.
Here's why:
The one time I did see catastrophic failure it was a brand new set of tires. The shop mounting them, their equipment had nicked the metal valve stem, on the inside of the rim where you couldn't see it. Then at 130 mph in Turn 1 at SIR the valve stem broke and ejected, and with no air the 993 pretty much immediately slid and rolled and crashed quite dramatically. (No injuries!)
But that doesn't fit the preferred narrative. After all it was new tires, and the cause traces directly to the "professionals" who mounted the tires.
07-18-2015, 06:08 PM
#29
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I don't care anything about internet trolling - whatever opinion you have is fine with me. But please, don't twist the facts. In my discussion with the Michelin tire engineer, he was not a sales rep, he was one of the design team and because this was a Mercedes factory sponsored event he was there to see how the big, heavy AMG cars - particularly the S class, were wearing the tires. If you choose to believe the conversation was not in good faith, that's up to you. We all know internet folklore is a much better source for the correct answer than a professional opinion.
I've been crashed out hard by two students while instructing, and one incident broke all the ribs on my right side as we impacted the tree line at T3 at Summit Point. So you'll have to excuse me when I say I won't get in a car at the track that has plugs in the tires, or dustless organic brake pads that melt away when they get hot. That's the voice of experience speaking ....however, you certainly are more than welcome to when YOU are instructing. Have fun, relax, he won't crash....
I've been crashed out hard by two students while instructing, and one incident broke all the ribs on my right side as we impacted the tree line at T3 at Summit Point. So you'll have to excuse me when I say I won't get in a car at the track that has plugs in the tires, or dustless organic brake pads that melt away when they get hot. That's the voice of experience speaking ....however, you certainly are more than welcome to when YOU are instructing. Have fun, relax, he won't crash....
07-18-2015, 09:12 PM
#30
Rennlist Member
Yes as I'm sure you noticed the man giving the advice to always just buy new tires does indeed sell tires. Isn't it funny how people trying to make a point will throw out details like that (I was talking to a TIRE REP!) forgetting that tire rep is another way of saying salesman, not exactly the profession you look to for candor.
You are also right about the crickets. I've had quite a few tires patched over the years. One on the back of my 911 was patched twice. Plus a few that were plugged. Plus I never follow the tread wear replacement guidelines. These are fine for people who sell tires, people who don't know how to evaluate tire performance, and people who write tickets. I am none of those so I replace them when they need replacing. Yet for all that I've never had a "catastrophic failure" - or even any indication of any sort of failure at all being even remotely imminent.
In drcollie's case I'd be concerned that he is not doing a good job of assessing risk factors in general. But as he says, reasonable people may have differing opinions on the subject.
The one time I did see catastrophic failure it was a brand new set of tires. The shop mounting them, their equipment had nicked the metal valve stem, on the inside of the rim where you couldn't see it. Then at 130 mph in Turn 1 at SIR the valve stem broke and ejected, and with no air the 993 pretty much immediately slid and rolled and crashed quite dramatically. (No injuries!) But that doesn't fit the preferred narrative. After all it was new tires, and the cause traces directly to the "professionals" who mounted the tires.
I have a friend who took delivery of a used 360 Spider a few years ago and didn't quite make it home from the dealership. I don't remember why the dealer monkeys R&R'ed one of the wheels -- I guess they were patching the tire (shudder) -- but while the tire patch job was just hunky-dory, their lugnut installation procedure was apparently in need of further refinement.