when to replace tire with inner tread wear

2/32" is considered the minimum acceptable tread depth (at the most worn part) of the tire according to everything I've ever seen on tires (when you're down to the wear bar, you have 2/32" left on the normal tread.. all tires have wear bars).  Get a tire tread depth gauge at Autozone or O'Reillys or use a penny.  Lincoln's head is 2/32" from the edge.  Don't depend on the wear bars because your tire might not wear evenly across the tread.  Just keep track of 2/32" tread in the most worn spot on your tire.

The issue with this problem is - once a tire begins to wear prematurely, the rate of wear picks up. It will take it longer to get to the point it is noticeable, than to get to the point it fails. Once you can detect wear, it will go faster. Then the issue is second and third order effects from tire failure, from as simple as loss of a fender to possible more dangerous things. You say it is not cost effective to replace a bent axle, but what is the effective cost of safety. I have no issue with the penny method of determining when to replace a normally wearing tire, but with a tire prematurely wearing due to other problems, it needs to be fixed not tested.

Are you sure the tire isn't rubbing on something in the fenderwell? Without a picture of the wear pattern, it's hard to give advice. And this is one tire, or both sides?

Happy Tripping,

My concern is the area that is wearing will have considerably less tread than the rest of the tire, which means it will run hotter, which means it will wear faster than the rest of the tread. There is no way to determine the time that will take, but rest assured it will happen. I see two possible solutions, first is to not fix the axle and replace the tires when the premature wear becomes noticeable or fix the axle. Once the wear becomes noticeable, and I'm only talking about odd wear, that wear will happen faster.