Previous tires were Kumhos. I just replace all because two failed. One front had tread separation and an outer rear blew and shredded on the highway while towing last week.

On the front now are BFGoodrichs T/A. Why? because I had to replace the left because of uneven wear. On the rear are Definity Dakotas H/T. Why? Because the Dakotas were the best choice at the Pep Boys which was a mile away after my rear tire blew on 95 south. I wanted to match up the rear so I did three more Dakotas. I could find no ill talk about the Dakotas or I would have gone another way.

What I have noticed is a floating sensation now. I felt it immediately coming home after the other three rears were replaced - no trailer. I really noticed it with the RV attached. It attaches via a standard rear hitch. It felt like the rear was steering. My guess would be the tires have more flex and when I turn the trailer which is nose heavy (1380 lb TW) it continues to nudge the rear to that side. A little scary towing on the back roads. A bit like steering a boat. Steer - counter steer. The bigger the initial correction the more back and forth until things settle out.

The hitch is a Reese WD and the receiver is a Curt (17000/1700)

Thoughts?

 

I think what you are experiencing is sidewall flex. Are the rear tires load range E?

 

Check to make sure you have load range E and the tires are inflated to max with that tongue weight. Also, what size are they, I have noticed on new tires on my Ex not so much on my F350 as it is DRW, is that they are squirrelly because of the height of the tread, more squirmy squishy,,,
But it does sound like you might have load range D tires, or not inflated correctly.

 

235/85 R16 same as the Kumhos. Load range E. Pressure was 70 psig which I set because they would heat. Max cold pressure is 80.

I've had the Kumhos at 80 and below 70 and never felt the floating with and without the trailer.

I wonder if the mixed tread might affect things - T/A on front and H/T rear.

Reg

 

I would try 80 PSI in the rear, and see how that feels for you.

 

not on a dually, but i've had this happen on a couple different trucks with brand new tires.

seems like once the tread broke in they squirmy feeling went away.

took a couple weeks each time IIRC.

 

What he said.

This happens with my tires too. It's caused usually by a narrow rim. It's squeezes the tire and it narrows your contact patch which makes it feel squirmy. I was pulled over for suspected DUI one night, which I think was over kill. It wasnt THAT bad. But it was 3am on a dark 2 lane road and someone called it in. The officer said he didn't observe anything. The interaction lasted less than a minute b

Although, I was in uniform

 

The website says nothing about the exact specifications of the tire: Tire Details Definity Dakota H/T | Pep Boys

It just says "Load Range E" which covers a wide variety of proper ratings. See Tire code - Wikipedia, the free encyclopedia for a representative list. Plus, proper specifications will give you a load rating when used singly or in a dual rear wheel configuration, which will be different (less per tire).

Could just be the break-in period. Could be an underwhelming tire for heavy towing.

 

New tires will have a round crown to them. This causes a reduced contact patch until they break in. Mud grips are the worst, and All-terrain a pretty bad, too.

 

Sounds like mileage may be the cure. I'll post when either the tires break in and behave or another solution is found including having had enough and replacing them. I'll give the latter plenty of miles before going that route say about 2000. Which is a bit under 6 months for me. I'll see about stepping things up.

It's not new tires I want but safe driving/towing. Things aren't dangerous just distracting and fatiguing making towing even more unpleasant.

Thanks for all of the feedback.

Reg

 

mine were AT's that did that to me. firestone transforce AT's were the last ones that did it to me. goodyear wrangler AT/S the time before that, FWIW.

i found that standing on it from a start made it squirm quite a bit too ... so i just stood on it every time until it quit doing it.

maybe not the best solution, but it worked.

1000-2000 miles sounds about right for break in.... either that or i just 'got used to it' ...

 

Pulled the trailer 86 miles highway with pressure set near 80 psig then on return trip dropped pressure to 65 front and 60 rear. The ride was much more settled. Some wandering but better. Will do about 30 miles on the back roads later this week and will post results.

Reg

 

Thank you for this post. I just recently bought a 2003 Ford f350 Super Duty Crew Cab dually 7.3L diesel truck. I'm about to buy it 6 new tires and never knew about these kind of problems let alone air pressure for towing and non-loaded pressure. This has been extremely helpful and good to know as far as what I may expect or experience once I install the new tires.

+1

 

Interesting timing on this post. On Friday I installed 6 245 70 19.5's on my F550. Went a size uo from the 225 70 19.5's that came stock. load ratings from 3700 to 4300 Lbs was the reason.
They went on the stock 6" rims. On the freeway ride home they felt a little loose even aired to 90 PSI. Wasn't sure what I was feeling. Makes sense now.

felt fine city driving to the office today so will hop on the freeway again today to see if it is still an issue.
Then this weekend the 3500 lb camper and M105A3 1 and 1/2 ton cargo trailer. Trip to the mountians to get out of this Az heat and take some dog food and toiletries to Yavapai College in prescott for the red cross on the way to Flagstaff.
A bit off topic but keep the 19 firefighters we lost yesterday and their families in your thoughts and prayers.

 

I've been reflecting on the wandering of the truck. I'm sure the tires may need some break-in and the sidewalls could be more flexible but the pressure is playing a part of it's own.

Thinking about how a tire works and how internal pressure affects it I think that at the higher pressures there isn't enough weight to flatten the tread thus I am riding more on the centers. Less tire on the road and less steering control. The truck is pivoting on smaller patches of rubber. With air released and pressure lower the tread flattens as it should making greater contact allowing the steering to better aim the front and the rear to be better planted. Now if pressure is lowered too much the tire rides on the outer edges as the center pulls away from the road. Less contact again and in this instance hotter sidewalls. Continue releasing air and the tread cups more and more until the tire eventually fails due to sidewall overheating or other mechanism.

I inflated the tires to a higher pressure thinking that they needed it because of the high trailer's weight particularly the WD hitch pressing down on the front end. However, the tires are built for that provided the correctly rated tires are on the vehicle. That is why it is so important not to deviate from the recommended load range, size, build and such w/o doing some real homework.

Reg