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.

[nomad297]

Goodyear does not make 15" load range E ST tires. ST tires all have a maximum speed rating of 65mph. if you have load range E tires, you should have them inflated to 80psi, but if you have Goodyear tires, you don't have load range E tires, so there's no telling what your psi should be.

Give us some correct facts so we can help.

Bruce

[DutchmenSport]

I do believe this is the first post EVER I've seen on RV.net where someone said (or admitted) they had problems with sway (or any kind of towing other than their TV being underpowered) with a 5er! Ever! (Maybe you should switch to a Hensley Sway Control hitch! :B :R That what they tell all the TT owners!)

[rhagfo]

BillPenn wrote:
Thanks for the suggestions. Seems reasonable that it may be light on the pin weight. The Dodge sits a good 6" taller than my Chevy did, could make a difference on the pin weight. I'll have to check that when I get it out next spring. I also checked the Goodyear sight, they recommend adding an additional 10psi if towing between 66-75 mph.

Does the 5er sit near level, if tail down that could cause your sway

[ol_Bombero-JC]

Follow the good logical advice others have given you.

Skip the sea stories by posters (someone passed me doing 85mph).
Gee Whiz stuff isn't going to solve your problem..:S

Start by dealing with "what you have".

*NOT* with what would/could/should be better.

Save that for "Round Two, Plan B" - or whatever you want to call it.
You may have to do that - but what you have *now* - is what you have.
There's obviously something amiss - or you wouldn't have posted.

For openers, tire pressure at the max pressure indicated on the sidewall of the tire.

(*IGNORE* the Goodyear "plus ten psi" recommendation.)

Determine the pin weight - by methods indicated.

Then determine if the trailer is level, and if not - work on getting it level......then repeat checking the pin weight.

One of the major advantages of a 5th over TTs is the lack of sway.

If you are encountering sway - without heavy crosswinds - there *IS* something wrong.

Almost everyone has gone over the "magic" 65mph - either accidentally or intentionally - without sway.

For those folks - guess your problem would be there at 66mph, and gone at 65mph = double duh..:R

~

[C-Bears]

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.

The E rated tires sound like they are under inflated to me at 55 pounds. But I am running G rated which I have inflated at 100 pounds (max 110) so I am not sure about that.

You need 20% - 25% pin weight. The only way you are going to know what you have is by going to a Cat Scale. Use the following fill-in-the-blank site after you get your truck weight and your combination weights and you will know all you need to know. When you go across the scale they will probably charge you $10.00. They will print out a scale ticket that breaks it all down for use on the listed below form.

http://www.towingplanner.com/ActualWeights/FifthWheelCatScales

Hope this helps.

[Leeblev]

Bill, if you have a DRY WEIGHT of 11,500, rest assured that you are pulling a lot more than that. I would agree with those that say your hitch/kingpin need adjusting to put more weight on the truck. HOWEVER, the tires only inflated to 55 lbs worries me for that much weight. I think you need to double check the tires to ensure that they are correct for your weight and also double check the inflation. Doesn't seem right.
The PROPER way to determine pin weight is what most suggested: Truck w/o trailer weight, then weight the truck ONLY with the 5er hitched and loaded like you will travel with. DO NOT put the whole rig on the scales, only the two truck axles.
Having towed a 5er with a dry weight of 9950 with a 250 diesel (total weight of the trailer was 12,450) and with the proper tires, I found that if I venture up to 70, I began to sway. I adjusted the hitch and it went away.
IMHO, that 3/4 ton is too small for an 11500 dry 5er.

[Mile_High]

filrupmark wrote:
Load range E can handle 80 Psi .but if your trailer is 11,500 dry those 15" tires are overloaded and not sized properly for your trailer.

Not if they are STs. STs are limited to 65 regardless of load range.

[BillPenn]

Thanks for the suggestions. Seems reasonable that it may be light on the pin weight. The Dodge sits a good 6" taller than my Chevy did, could make a difference on the pin weight. I'll have to check that when I get it out next spring. I also checked the Goodyear sight, they recommend adding an additional 10psi if towing between 66-75 mph.

[filrupmark]

Load range E can handle 80 Psi .but if your trailer is 11,500 dry those 15" tires are overloaded and not sized properly for your trailer.

[wilber1]

I don't see a E rated 15" Marathon listed by Goodyear, only D's. Regardless, the first thing I would try is inflating them to the max sidewall pressure. Easy to do and costs nothing.

[larry_barnhart]

I have seen a new 3500 Ram towing a toy hauler that might have been brand new and the hauler was all over the road because of a little wind from the side.

Not thinking it was the truck but as said above not enough pin weight if that was possible. E tires on the OP on a 15" wheel and 55 lbs of air pressure seems to confuse me.

chevman

[rhagfo]

Merrykalia wrote:
I was coming down I-81 in Virginia last Thursday afternoon, traveling along between 70 and 75 mph. Posted speed is 70.

I am not towing, just have the truck and I see in my rearview mirror a good size fiver heading towards me. I could see the trailer wandering around when he was still behind me. He passed me, going at least 80, but probably closer to 85. There were Louisiana tags on the trailer. He was taking up every square inch of his lane with all the wandering around that the trailer was doing. It was really scary.

Like I said my 5er tows GREAT!!! :B :S

I don't think I would want to be doing that!!!

[Merrykalia]

I was coming down I-81 in Virginia last Thursday afternoon, traveling along between 70 and 75 mph. Posted speed is 70.

I am not towing, just have the truck and I see in my rearview mirror a good size fiver heading towards me. I could see the trailer wandering around when he was still behind me. He passed me, going at least 80, but probably closer to 85. There were Louisiana tags on the trailer. He was taking up every square inch of his lane with all the wandering around that the trailer was doing. It was really scary.

[rhagfo]

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

Go to scales either Cat or state on weekend when not in use.

Weigh with 5er attached, front axle, rear axle, and trailer axle.

Drop the 5er, and weight just the truck front axle, and rear axle.

The total truck axle weights towing, minus the total truck axle weights not towing equal the pin weight.

[Dennis_M_M]

I can run 75 easily with no issues, but we travel with the cruise set at 62-63 MPH. Most comfortable speed for me and the sweet spot for the truck where the MPG is the best. I find it much more relaxing at that speed and since we only stop for fuel every 2,000 miles we get there just as fast.

When I am in traffic and coming up on a slow moving vehicle I will push it up to the general speed of the traffic so I am not blocking the left lane.