wwrx

iTrader: (5)

Any tire experts here? I mean real ones I know that everyone think that he/she is an expert (including myself)...

I posted my queston on IWSTI but will copy it here.

Replace track tire after the fire "damage" or not? - Subaru Impreza WRX STI Forums: IWSTI.com

"To keep the story short - my car went through an engine bay fire during an AutoX a few month ago. Some of it went through the fender arch and melted fender liner that landed on a passenger side front tire. That melted plastic has been scabbed off and seems like did not do anything to the tire contact surface. Tire has no balancing issues and etc. However, there is a burn mark (from an open fire) on the inside tire wall. Just at one spot. Here are the pics:

https://www.dropbox.com/sh/t81f1a26vxdki0s/qKurAEPa1r

Tires are 275/35-18 Hankook RS-3s

The whole fire lasted 30-40 seconds as there were workers with fire extinguishers.

"Burned" sidewall spot feels the same as the rest of uneffected sidewall when being punched, pressed and etc. Seems like only the surface has been effected.

So, this tire seems to be fine for DD use. But I use this set on track also and tires go up to 160-170F (measured right after the session).

My local tire shop (race shop also) says that it may be OK to track this tire but it's up to me as they are not 100% sure (no blame on them for that) of course.

What would you guys recommend? I understand that the decision is on me and nobody's responsibility here. Should I go ahead and order a new replacement tire (~$300 shaved and delivered)?"

JelloChex

iTrader: (6)

I'd agree with the recommendation of putting the tire to the back for continued use.

Do you have a Tire Temperature Gauge yourself or is someone else at the track using one for you? If it was me, what I would do is do normal street driving sessions with the tire for now and then measure the tire temperature on each of the tires and see if there is any difference between the tire that came from where the fire damage dropped on to it and the rest of the tires. If no difference on the street, then maybe try a lap around the track and check again. If still no difference, then do a full course and check one more time. If still no difference between the 1 tire and the other 3, then I would think that there would think that the tire would have only sustained potentially surface damage that would be or already has been worn off through the driving sessions.

However, if there is any noticeable differences then it may not make sense to continue to use that tire. It might make more sense to replace that tire with another one if there does seem to be any noticeable issues.

wwrx

iTrader: (5)

flukewrx, thank you! Good idea. I do have a cheap IR temp meter but I guess absolute numbers don't matter here, only relative numbers matter. Are you suggesting measuring the sidewall temps or thread temps (or both)? I DD on that tire since the end of Febuary but never checked temps.

I used to check my tire temps on the track but stopped doing that as there is a nice shop there that does it there for everyone for free (Big-O-Tire guys that track with Hooked on Driving).

What do you consider as a noticeable difference in temp on street (not track)?

Thanks!

JelloChex

iTrader: (6)

I think you have a link to a picture of the damage, but unfortunately I can't see it here at work (picture hosting websites are blocked for some reason).

I would check all around the damaged area (both sidewall and tread areas). I think the track guys could probably give further advice as to what kind of swing may or may not be acceptable. The range that could lead to a cause for concern may be different for Street vs Track Driving so I'm not fully certain, but I would think that at least for the street driving portion (which is where I would start at) that within a few degrees, probably not of a problem. Something along the lines of 10 degrees or more of difference and that could lead to potentially cause for concern.

JelloChex

iTrader: (6)

Also, keep an eye out for the obvious tire issues, like bubbling / blistering of the tire around the damaged area (I'm sure you are already checking for this, but just putting it out there).

STi-owns-evo

iTrader: (4)

Structural integrity of a tire's sidewall comes from the steel belt underneath the vulcanized rubber. A melted piece of plastic doing, what looks to be, surface damage to the rubber should not have affected these belts. I would honestly not worry about anything happening.

However, it wouldn't be a bad idea to just periodically check, as I can't really say how much damaged happened underneath what I can see.

04GG

iTrader: (33)

If it chunks/bubbles right there like these guys are saying, then you have an issue. If it not, it should be fine.

If there is an expert here, it is probably Fluke

Lowend

iTrader: (5)

I'd call that tire done. Sidewall is almost certainly weakened.
If you are autocrossing, than you are putting huge stresses on the sidewall.
Better safe than sorry, you don't want a catastrophic failure

slow04wrx

iTrader: (3)

uh buy a new tire? Or maybe you could cut off a block of this one send it in for some lab testing you know........it's betterer to make things in life simple instead of overly difficult.

JourdanWithaU

iTrader: (39)

I'd still run it. I'd keep an eye on it and be mindful of it. If you're really uneasy, put it on the back. Since the tire is directional, you can't really pick a side. Hopefully it will be on the inside side of the car. It will see less abuse from the inside back corner.

I haven't looked at the photo, but if it isn't more than discolored (blue) I wouldn't be worried at all.