I think what mr. losi is looking for is how long do they last before the performance goes down hill. I can run tires two years old but are they just as fast as when they were new, probably not.

I guess the only way to find out is to try a new pair.

So lets ask this, how many runs are people getting before you decide to bolt on a new set because you are not fast enough? The other question is are you cleaning the tires with anything? Just trying to find any similarities that might exist.