I've got 25k on an '05 RS Wagon. I'm trying to decide if I need to replace the stock Potenza RE92's. The tread on the fronts is about 1/16th above the wear bars and the tread on the rears is about 1/8th above the wear bars. In theory, this means I don't need to replace them. However, the outtermost tread blocks on the inside and outside of the tire are just _gone_. It's a solid bar of rubber all the way around. And before you chide me for letting the air pressure drop, I've been running them at the max printed on the tire. The reason I'm worried about the tires is that with the solid band of rubber all the way around, there's no way for water to get out from underneat the tire. This theory is supported by the fact that I understeer like a hyena in the wet now and I've actually hydroplaned at 70mph on the freeway.

So... "acceptable" tread depth in the middle, solid bands of rubber on the edges, already at max air pressure...

Do I need new tires?

 

I've never gone by depth measurements or anything. When the tire doesn't feel safe anymore it doesn't matter how much tread it has left. I replace them before they get passed worn.

Like you said, you are having unsafe things happen because of the condition of your tires. I'd say it's time for new ones. Rubber keeps you on the road.

 

http://www.tirerack.com/tires/tirete....jsp?techid=51

YWIA