I just picked up my new 30' travel trailer today and hooked it to my new F-250 that I just properly broke in. There were stretched of road where my steering wheel was cocked off to the right a good bit. While my steering wasn't affected in an unsafe way it was alarming as if something was tugging a good bit to that side. It never happened to the left. On other stretches of road it was perfectly straight as if there was nothing being towed. Any ideas?

 

Only when towing?

 

Yes. And only on certain stretches of the drive. The guy accomplishing the PDI test drive with me was stumped.

 

Since this is an "only while towing" phenomenon, I would scale it first to see what you have in terms of weight distribution. I would expect a trailer alignment issue to be continuous and if a truck issue, it should be hitched and unhitched.

Nothing obvious I am guessing. Can you replicate it, for example always on one type of road, over the same spot traveling only in one direction which would suggest the cant of the road, etc.?

 

our stock trailer pulls to one side. it also wears out tires at an annoying rate.

it was also in a wreck, so it surely has an alignment problem.

so, yes, a trailer with an alignment problem can cause your truck to pull when towing.

as for it occurring only on particular roads, not all roads are the same. some county roads are built steeper than state roads, and some old roads are built with a "quarter crown" where the middle part of the road has a different slope than the outside of the road. some very old roads may have no crown or even an inverted crown.

so if you had a trailer trying to pull the left, and were driving on a road with no crown, or an inverted crown, you may find yourself steering right quite a bit more than on a road with a 3% crown (2% is the standard, 3% is used on some county roads for better drainage).

short term, try to take note of which roads it happens on. if possible take a long level with you and measure the road's cross slope. 1/4" per foot would be the norm. so if you take a 3" level with you, the road should drop 3/4" in that 3 foot. the longer the level the better, but use what you have (we use 10' as our standard, but that's not practical for most). This may give you a clue as to why some roads are worse than others.

long term, look at your tire wear and see if that tells you anything. the tires on our stock trailer generally wear out in about 3 years. for us, that's only 9,000 miles of towing .... so if you are going through tires quickly, this may tell you why. for us the front tires on the trailer wear twice as fast as the rears, so to get 3 years out of a set i end up rotating them front to back about 2 years after buying them to squeak that last year out of them.

if you can establish that it is the trailer, perhaps by hooking to another similar trailer, maybe you can make the RV place either fix it or swap for another, since it is new?

not sure if any of that helps or not.... good luck!

 

Thanks. Bad news is I can't figure anything out for another week or so when we bring it out the first time. Good news is I had the PDI tech in the truck when he saw it was occurring. The last thing I need is the new trailer screwing up my new truck. Nothing but negative things with this trailer so far and it hasn't even been used yet.

 

A couple things I would do - a trailer weight distribution check at a CAT or similar scale and then a quick alignment check with a string or long tape measure (50' or so) if you have one. Using the hitch center, measure to the same point - spindle center, spring plate center, etc. They should be very close to identical but my guess is within 1/4" would be acceptable.

Of course an off camber road or high crowned road can cause some 'dog legging'.

Then, are your weight distribution bars the same - 500/750/1000 pound? And are they pulled up on the same link and by the same brand trailer tongue bracket?

Are the tires inflated to the trailer manufacturer's spec?

Do you have a brake dragging on the trailer?

 

I had this happen with a truck/trailer combination that was just a couple of years old and thought the problem was in the trailer. I measured the trailer setup six ways from Sunday and could not find any variation. I attributed it to dynamic forces on the torsion axle that allowed it to move slightly.
Then, I pulled another trailer and found that it too had the problem.
Overall - It was not dangerous at all, just crabbed the steering wheel a bit off center..

Bottom line was that it was in the truck.
The u-bolts in the right rear spring pack had never been properly torqued and the axle would actually tweak a little under heavy loading of towing a 10k trailer. I found it when I went to service the differential lube and saw a different shade of rust in the spring pack area.
When I fixed it, I torqued the bolts with the truck on the ground so the spring pack was partially compressed. No more tweaked wheel after that..

 

Never would have thunk it!

Steve

 

If you are using a new equalizer hitch, make sure it’s internal friction surfaces are greased, or it may stick off-center, and it’ll try to steer your truck from behind.

 

Same here, after I replaced the 3.73 for 4.30 (whole rear end) in my Excursion, only noticed it towing. Retorquing the u-bolts fixed it.

 

Heavy cross wind?

 

Shouldn't be a "bump steer" issue, but that comes to mind especially if the height of the front of the truck is significantly different with the trailer attached?

 

I suppose that could be true if the axle was centered longitudinally under the leaf spring differently on one side. That is to say, if the leading end of the leaf spring was longer on one side, as the spring compressed the axle would move aft farther on that side as the springs compress.

 

Bump-steer is happens when the up/down movement of the axle causes the lateral distance between the frame mounted components and the axle mounted component to change, so the fixed length drag link causes the rotational components (e.g. spindles) to move. Simply put, the up/down movement of the axle causes the vehicle to steer to one side or the other.

What I suggest would be the effect of a "semi-permanent" change of the axle to frame distance due to vehicle loading. But modern vehicles are designed to minimize bump steer, so it's unlikely this is the cause, unless a bad lift has been done, wrong parts installed, etc.