Do you have any adjustability on the rear shocks? Could be underdamped back there. Is it an airbag car?

The tow vehicle is a 2012 Jeep Grand Cherokee with the air suspension (tow package). I can't customize the pressures, but this version tows better than my 2006, so I'm willing to put my money on the tires. After more research the stock Goodyear Fortera tires get horrible reviews and do not have the stiffer sidewalls that would help in towing (like the General Grabber that I had on my previous tow vehicle). Seems to make good sense to me, so I'll just deal with it until it is time for some new tires.

If there are other ideas please post and I'll check it out.

Thanks,
-Skip

Something similar happened to a friend of mine. He had a horrible shimmy above 55mph. Changed rear shocks, no difference. Next trip a trailer tire blew out. Put the spare on and the shimmy was gone. I would carefully check all four trailer tires.

Pete

Pete,

Thanks for sharing. I'll take a good look at the trailer tires before my next tow to make sure they aren't the problem.

-Skip

Shimmy at higher speeds? Sounds like a balance issue with your Jeep or the trailer.
Were your trailer tires ever balanced? Most new trailers are delivered with unbalanced tires since they don't expect you'll exceed 50 mph (remember the 45 mph speed limit on U-Haul trailers? I assume you're actually cruising at 70?
How many miles are on the Jeep tires since the were last balanced?
Even good tires go out of balance as they wear or sometimes they simply throw the weights.
If the trailer tires were never balanced or you're in doubt, balance them.
For your Jeep, if you have the tires rebalanced, use a shop that takes time to reclock the tire on the wheel (to minimize weight required to balance) and consider using a shop that Road Force balances the tires which accounts for diameter fluctuations of a rolling tire.