I picked up my Evo X from the shop where I was getting things fixed and some goodies put on, including a new set of Hankook RS4s. I put about 400 miles on them commuting and then went up to Thunderhill for a track day yesterday. First 20 minute session was about 40 degrees and a bit damp. Second session was sunny and the track was dry. About fifteen minutes in to the second session I noticed the car pull when braking into turn 1. I finished up the lap at a brisk pace and returned to the padlock and found I had a flat. Picture below,

Two questions. One, is this damage likely due to a tire defect or is it just from driving almost three miles to get off the track. Two, can I get away with just replacing the one tire or do I need to at least replace two?

 

Many factors that aren't mentioned but likely All of the above, pressure loss, deflection from running at said lower pressure, and a bit of a thin wall height and a bit over stuffed on the rim size. It all adds up eventually. Two newer ones on the fronts if the other is below 3/32's.

 

That has low pressure written all over it

 

Yup, needed more tire pressure. I would replace just the one and call it good since you only put 400 miles on them. It will of course depend on how much track wear they all have. You might be able to find just the one you need used online and already worn down to the level you need it.

 

Thanks. Both have well over 3/32, so I'll probably just get one. They are on 9.5" rimes. I reported the problem to Tire Rack but I'm not really expecting them to replace it.

Pressure was definitely fine at the start of the session. I looked at the left and right tire speeds on my AIM and it looks like something went wrong on the last turn and I took turn 1 slower than usual, but still fairly quick. So I was definitely run with little or no pressure for almost three miles before exiting the track.

 

If you can't find a used one that matches, you could get a new one shaved to match the others.

 

What does the outer side wall look like? Do you see a puncture anywhere?

 

Can't see any punctures and side walls look almost like new. They should be coming off today ... the new tire was stuck in Reno last week.

 

If a tire was run low, it will effect both sidewalls, not just one. Inspect and take pictures of the inside and outside of the outside sidewall for us. We'll be able to tell if it has run flat damage. Having one sidewall pristine and one sidewall ruined points to something other than low pressure; either something cut it or the tire was defective.

 

Replaced the one tire and went to the track last Sunday. The RS4s rock and I finally finished a complete track day. I suspect the other tire was defective but the tire's gone and I really don't care at this point,