Really Weirdo tire wear...

I've been auto-xing the crap out of my car lately and the front tires are showing some really weirdo tire wear.

 

My tires are Falken ST-115 they are designed with a center treadblock 2 rain channels and 2 outer treadblocks.

 

http://www.carsound.com/reviews/performance/falken_Azenisst115.jpg

 

My problem is that the OUTER edge of the INNER treadblock is worn almost to the wear bars. around 1/16ths

 

The OUTER edge of the OUTER treadblock is still around 3/16ths like the rest of the tire.

over pressure

+1

40 psi is pretty normal pressure for autox... but ill try bumping it down next time.

wouldnt over pressure wear the center of the tire??

yes it will... but im surprised that it wore the outer edge of the inner treadblock the most.

 

the inner edge of the inner treadblock is fine as is the outer edge of the outer treadblock

How's your camber?

sounds like a combination of:

 

Toe, camber, and possibly under pressure since you are probably experiencing some roll over.

 

Camber will wear that inner edge

Toe-in is scrubbing away your outer edges

Under pressure can scrub both ways on each end

Im not getting any abnormal inner edge wear.

 

Im also not getting any abnormal outer edge wear.

 

Im getting abnormal wear ONLY on the outer edge of the INNER tread block.

 

My camber is 1.8-2.0 with an increased KPI and I am actually toed out slightly.

 

I can go in hot and understeer all I want and I get no extreme outer edge wear. Im just getting really weird wear on the inner treadblock.

 

 

Im too cool for paintbrush...

 

http://i49.photobucket.com/albums/f277/RobY6298/Picture.jpg

Overinflation + aggressive driving.

Overinflation + aggressive driving.

 

+1

40 psi is pretty normal pressure for autox... but ill try bumping it down next time.

 

I'm not an autocross expert but I do know that if you were to run 40psi cold on a road course you'd definitely get some abnormal wear and funky handling to boot. Tires heat up a ton and as you probably already know build up pressure as the air in the tire expands. Do tires get up to the same temps on an autocross course?

 

I used to set my STI tire pressure at 32 cold before getting on the track; within one session they'd be pushing 42+

Not even close to track temps. Its only a 1 minute run with alot of waiting inbetween. You will be lucky if it gets up to temp midway through the course.

With that 1 minute run.. I can easily build up 3 to 4 psi per run and I would have to bleed off every run.. after 4 runs (at under a minute I would had a total of over 12 psi to bleed off.

 

On the track, tires start to slowly melt around 250F (see marbles on the track, it's the liquid of the rubber cooling while tumbling in the air).. running 160F to 180F at an autocross is where you want to be.. anything higher than that and you are not getting what you need out of the tire. Did you ever get temp readings off your treads? I think you should and see if you are over inflated and running way too high of a tire pressure. The "I can understeer all I want" is probably what is making it chunk off and creating that odd tire wear, especially with braking and cornering.. my track tires look like that as well from some sets, it's from the over-inflation during the driving around the track... gotta start lower psi's and let the tires build up to the correct operating temps.

 

Is it just the front tires that's giving you this wear? It's possible that it's over-inflation.