More tire talk! Tracking with a patched tire?

Chad Culbertson · **Posted:** Fri Jul 03, 2015 12:58 pm

Is it safe, apparently the world doesn't like my tires just like me, but I'm not really to go out buying new ones yet.

I thought I picked up some gum at Danville but turns out it's a freaking roofing nail. This is the second object these tires have picked up, unfortunately, I'm pretty sure this one actually has punctured the carcass.

It's in the rain groove and should be more than far away from the sidewall to patch. I'm just not sure I feel comfortable doing 140mph on a patched tire.

Bernie Baake · **Posted:** Fri Jul 03, 2015 4:10 pm

" I'm just not sure I feel comfortable doing 140mph on a patched tire". I think you answered your own question. A good rule of thumb is, when in doubt---Don't do it.

RobLupella · **Posted:** Fri Jul 03, 2015 4:40 pm

I tried to kill them :twisted:

I agree with Bernie, It may be OK, but do you really want to find out you were wrong. Tell your wife its a safety thing that you have to get new tires so you won't get killed :-)

This might be a good opportunity to get new wheels. Put the new tires on and get the old tire patched and use them for street and use the new ones for track/Ax

Chad Culbertson · **Posted:** Fri Jul 03, 2015 6:05 pm

RobLupella wrote:

I tried to kill them :twisted:

I agree with Bernie, It may be OK, but do you really want to find out you were wrong. Tell your wife its a safety thing that you have to get new tires so you won't get killed :-)

This might be a good opportunity to get new wheels. Put the new tires on and get the old tire patched and use them for street and use the new ones for track/Ax

It certainly is a good excuse, the inside of the tires are down to 4/32nds anyway, although for some reason i'm 99% Mickey Thompson molded them with more tread on the outside than inside, no clue why.

The deepest is 6/32ns, but i'm not sure what they started out with. It really wasn't in the budget to buy new wheels and tires, but I guess we'll see what happens lol.

The tires only have one HPDE and I think 6 autocrosses so far.

Cash Davidson · **Posted:** Fri Jul 03, 2015 6:10 pm

I've run with a plug in my Mazda - several times. :oops:

But I'm speed limited to 120mph.

Never had any ill effects. IMHO, if the plug fails it's likely to be a slow leak. I just kept a close eye on the plug and the pressures.

Just keep in mind that my intuition nearly makes up for my poor judgement. :lol:

YMMV,
Cash

Chad Culbertson · **Posted:** Fri Jul 03, 2015 6:20 pm

Maybe this is a good time to trade it for a FR-S/BRZ or a Mini, haha. It's been on my mind for a bit anyway, the consumables cost of the Camaro is getting pricey and I have too many hobbies to do them all.

I'll get it patched anyway just because I need to drive the car, guess i'll make up my mind whether i'm comfortable running it at VIR or not. I don't see much issue in autocross so it'll still get run for autocross.

JasonWatts · **Posted:** Fri Jul 03, 2015 10:08 pm

Chad Culbertson wrote:

I'll get it patched anyway just because I need to drive the car, guess i'll make up my mind whether i'm comfortable running it at VIR or not. I don't see much issue in autocross so it'll still get run for autocross.

Have not been in your shoes but I would feel this way. Ive carried some serious lean angle on a patched rear MC tire. Patch has held just fine... the stickyness of the patch might have even given me some extra grip.

I have pushed tires on the street plugged (not that any member of this club would ever brake a single traffic law). If you have the option, you can always rotate your tires to the back if its not already there.

Chad Culbertson · **Posted:** Fri Jul 03, 2015 10:36 pm

JasonWatts wrote:

Chad Culbertson wrote:

I'll get it patched anyway just because I need to drive the car, guess i'll make up my mind whether i'm comfortable running it at VIR or not. I don't see much issue in autocross so it'll still get run for autocross.

Have not been in your shoes but I would feel this way. Ive carried some serious lean angle on a patched rear MC tire. Patch has held just fine... the stickyness of the patch might have even given me some extra grip.

I have pushed tires on the street plugged (not that any member of this club would ever brake a single traffic law). If you have the option, you can always rotate your tires to the back if its not already there.

It's in the front currently and I do have the option to rotate them since I went squared on the Camaro, from the factory they come with staggered wheels. I'm now running stock rear wheels on all 4 corners.

Arthur McDonald · **Joined:** Fri Aug 29, 2003 1:54 am **Posts:** 2052

I'd go with Bernie's advice and replace the tire, or a pair of tires. Having a tire go down suddenly (or even slowly) on track can turn into a big event. Tires are wear items, you have to be ready to replace them when necessary.

Moving the suspect tire to the rear isn't really an option. A flat on a rear tire at speed probably means a spin and completely uncontrolled exit from the pavement. If a front tire goes down, you'll probably feel it through the steering wheel right away, but in the rear, sometimes you don't know until you apply a side load.

Regarding repairing a tire, a patch is better than a plug. Installing a plug requires gouging a larger hole in the carcass and steel belts than the original injury. And if the hole is near the shoulder, the repair is more likely to fail.

Now about that inside shoulder wear, how much toe out are you running?

JasonWatts · **Posted:** Sun Jul 05, 2015 2:07 pm

Arthur McDonald wrote:

I'd go with Bernie's advice and replace the tire,

Agreed completely

Arthur McDonald wrote:

Moving the suspect tire to the rear isn't really an option. A flat on a rear tire at speed probably means a spin and completely uncontrolled exit from the pavement. If a front tire goes down, you'll probably feel it through the steering wheel right away, but in the rear, sometimes you don't know until you apply a side load.

All good points. As you said in a part I removed, even if the tire goes down slowly it will change the way the car acts. I still thing any decent non dimwitted driver should be able to feel how their car is acting and try and stay within the limits of the car and get off the track if it starts behaving poorly or worse. Also if he is driving this car on the street you will have a decent idea if its going to hold air or leak.

All that being said, move it to the rear, get some tires ordered an put them on before you push it repeatedly

Chad Culbertson · **Posted:** Mon Jul 06, 2015 1:01 pm

Apparently the common practice now is a plug combined with a patch. The plug seals off the belts from getting water in and corroding down the road, while the patch helps seal it from leaking better.

I think I probably won't track this tire, but it might be worn out before VIR in September anyway at this rate.

As far as the toe out question, I had 1/32" toe out on each side so -1/16" total. I'm going to set it to 0 toe, it's also possible something has moved since the alignment was done.

At least the benefit of having TPMS sensors and a DIC that will display individual tire pressures I should be able to easily catch it if it does leak. I typically leave my tire pressures displayed during AutoX and track so I can keep and eye on where they are.

Arthur McDonald · **Joined:** Fri Aug 29, 2003 1:54 am **Posts:** 2052

How frequently does the TPMS sample tire pressures?

I have personal experience with not noticing a deflated right rear tire (down to about 15 psi) in a Civic hatchback. With little weight on the rear tires, the tire did not appear to be low, and things felt OK until I pushed the car hard into a left hand sweeper in an on-ramp. One deflated tire really changes your diagonal corner weights!

George Bright · **Posted:** Thu Jul 09, 2015 8:38 am

Art's experience might be due to the fact that some cars do not monitor tire pressure directly. They measure speed of rotation when the steering is straight. If one wheel starts spinning faster then the system decides that tire is going flat. This is an inexpensive way to add monitoring since the speed sensors are already in place on most cars. the other flaw is if all the tires loose pressure equally.

If Art had been carrying a dead body in the back of the hatchback then his low tire warning would have come on sooner.

Chad Culbertson · **Posted:** Thu Jul 09, 2015 8:46 am

It samples it quick enough that I used it to adjust pressures during autocross, i'm not sure of the exact number.

The tire is all patched up now, we'll see if these tires have enough tread left for VIR Full in September, they might not, so the patched tire might not even matter.

DickRasmussen · **Posted:** Fri Jul 10, 2015 12:53 pm

Arthur McDonald wrote:

How frequently does the TPMS sample tire pressures?

I have personal experience with not noticing a deflated right rear tire (down to about 15 psi) in a Civic hatchback. With little weight on the rear tires, the tire did not appear to be low, and things felt OK until I pushed the car hard into a left hand sweeper in an on-ramp. One deflated tire really changes your diagonal corner weights!

Art - Per the FSM CD's 2012 and 2015 Mustangs update every 60 seconds. These cars, as you know, use sensors in each wheel. The 2015 Mustang displays individual wheel tire pressures. The displayed values are within about 1 lb of what my gauge indicates.

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More tire talk! Tracking with a patched tire?

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