5er sways over 65mph

[BillPenn]

Have a 2014 Dodge 2500 Crew Cab 6.7L Diesel pulling a 32’ Thor 5er (dry weight 11500). New truck pulls great with plenty of power to spare. Only one problem, if I get over about 65 mph the rear of the trailer will start to noticeably sway. Can’t feel it in the truck, but you can see it in the mirrors. If I slow to below 60 mph it will stop. I replaced my tires this year with new Good Year ST225/75R15 load range E, and have them inflated to the recommended 55psi. With the trailer hooked up it sits fairly level, maybe a little down in the front. Any suggestions on stopping this, or is it normal? Not looking to do 90 but would like to maintain the speed limit.

[jfkmk]

The ST tires are only good for 65 MPH anyway, why push it?

[fj12ryder]

Weigh your truck without the 5er, then weigh it with the 5er hooked up. The new weight of the truck minus the old weight of the truck is your pin weight. With your 5er it should be around 2200-2500 lbs. If it is less than that it could be your problem.

A wandering 5th wheel is a pretty rare breed.

I don't blame you for wanting to drive over 65 safely. Sometimes it's necessary, and you don't want to be worrying that you won't be able to control your truck and trailer.

[BillPenn]

Hitch is above the axle. How do you measure the pin weight?

[chevor]

Don't drive over 65

[dbbls]

Sounds like you may be light on pin weight. No reason a properly balanced trailer would sway. Pin weight should be about 20% of the trailer weight. Where is your hitch mounted in the truck. Is it above or forward of the axle? If it is mounted too far back this could also cause this problem.

[rhagfo]

BillPenn wrote:
Have a 2014 Dodge 2500 Crew Cab 6.7L Diesel pulling a 32’ Thor 5er (dry weight 11500). New truck pulls great with plenty of power to spare. Only one problem, if I get over about 65 mph the rear of the trailer will start to noticeably sway. Can’t feel it in the truck, but you can see it in the mirrors. If I slow to below 60 mph it will stop. I replaced my tires this year with new Good Year ST225/75R15 load range E, and have them inflated to the recommended 55psi. With the trailer hooked up it sits fairly level, maybe a little down in the front. Any suggestions on stopping this, or is it normal? Not looking to do 90 but would like to maintain the speed limit.

Do you have enough pin weight?

Might check Tire pressure, and check the alignment on the 5er.

Many will hit on you for towing 65, I can creep up on 70 real easy, but don't have the rear end wander you speak of.