Back in August, I had a similar problem with tire wear after 8000 miles. Tire pressure was kept to tire manufacturer's specifications. TT has Lippert axles and is still under warranty. I called the dealer's service department and their initial suspicion was a bent spindle. I was under a time crunch to get the problem resolved between scheduled camping trips. The dealer asked if I was willing to do a few measurements to expedite the diagnosis which would identify next steps.
Lippert provides the warranty for the axles. I called Lippert Customer Support and they assigned a Case Number. Lippert emailed a sheet with instructions to measure toe-in alignment.
https://www.lci1.com/assets/content/...CD_0001949.pdf
After sending the measurements to Lippert, Lippert then requested:
*full vin
*date of manufacture
*date of purchase
*make
*model
*manufacturer
*pictures of the issue suspension
*picture of AXLE serial tag picture
*picture of 4ft level under axle beam
*picture of front and rear of unit
Based on the measurements and additional information supplied from the above list, Lippert authorized a new axle beam due to bent spindle.
I contacted the dealer's service department with the Lippert Case Number and they worked out the warranty details with Lippert. It took approximately 10 business days to manufacture and ship axle to dealer.
Replacement of an axle beam requires removal of leaf springs from the shackle links. I asked the dealer to replace the nylon bushings with wet shackle bolts on both axles, which I paid for. Two of the nylon bushings were getting thin, so I am satisfied with upgrading to wet shackle bolts.
After the axle replacement, I replaced all four Rainer TT tires with Goodyear Endurance trailer tires.
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