We have a 2001 32'TT. This reason alone makes me think twice about replacing it. it scares the heck out of me as I do not have any poor tire problems and no need to concern myself with an alignment issue. Close guess as to miles on the trailer are around 35k-40k. Tires have been replaced primarily when a tire would blow...at which the whole set got replaced. Current set was replaced in 2016 with D load range and wish I had done that earlier in its life. Up to this point they were C LR tires. The D's just make this thing tow better.