Unusual tire wear

[jhall299]

Hi,

Can anyone shed some light on this tire wear pattern? The inboard side of the tire is to the left. It is a little hard to see but about 1/4 to 1/3 of the way out from the inboard side is a pronounced hump. The outboard half of the tire is reasonably evenly worn. The tire was on a Boxster and they are Pirelli Asimmetricos.

Thanks,

Jon

(edit - removed double image - Loren)

[nick49]

Inboard tire wear is from negative camber. You can correct this but your car will not handle as well especially when driving agressively. Racers often add a little more negative than what is used for street cars to aid in quicker turn in or more more stability in the turns. The hump you see is from too little air pressure, as this is the most loadbearing part of the tire footprint with your current camber setting. It would be more centralized with no negative camber. Too little air makes the tread push inward or toward the center of the wheel and creates little wear in this area, but more on either side. A side note is that recommended air pressures are a good starting point and probably a good average for a stock car. but depending upon the ambient temperature, road surface type, desired handling, speeds to be driven, suspension settings, spring rates, dampening, tire compounds, tire widths and possibly other factors, it may ideally very.

[986Jim]

I also notice on the left side of the tire on the second set of block in, you can see where the top part is grey from the floor and the lower part is dark.

My tires are doing this as well and I'm not sure of the cause. Its like the front part is wearing more than the rear part of the tire tread. Is this from it being old or the camber or what is the cause? I have notice that there is a bit of shake from the wheel at ceritan speeds. I adjusted the pressure to what it says in the manual (29psi and 36psi rear if I remember correctly) but it didn't really help.