Effect of un-level trailer

joshuabardwell · May 16, 2012

I just picked up a weight-distribution system for my truck/trailer. The hitch receiver height is about 22". The coupler is about 15" high when the trailer's level. The coupler is about 20" high when the trailer is on the ball, with the head at its lowest position on the shank. My inclinometer shows that this puts the trailer about three degrees high of level.

Is this a big deal? Do I need to pony up the $100 or so for a shank with sufficient drop?

FWIW, it's a 7000 lb dual-axle utility trailer, and I do tend to load it to 3000-5000 lbs more often than not.

jeffsw6 · May 17, 2012

The inclinometer is not necessarily telling you the whole story about tongue weight vs gross trailer weight, and truck squat. To tell the truth, it really is not a useful tool in this situation.

You could put 1000# of tongue weight on an F350 and might not even be able to tell there is a load on it. Put the same thing on a Tacoma and it is likely to be unsafe. On the F350 your level might tell you the tongue is too high because the F350 has really big rear springs and it just doesn't squat that much, yet the trailer may be easy to control. On the Tacoma your trailer would be closer to level but the Tacoma would be losing weight from its front axle and it would be hard to steer.

joshuabardwell · May 17, 2012

I guess I'm not really sure how to interpret what you're telling me. Sure, different trucks are going to squat different and ride different with different amounts of weight on them. I get that. I've got a WD system, so I should be able to control the amount of squat that way, right?

I had always been told that it was important to have the trailer ride level, so that the weight was evenly spread across the axles. Basically, I'm trying to figure out whether I need to buy the new shank to get the trailer 100% level or not.

Diamondpilot · May 17, 2012

Industry standard is 18" from the ground to ball top unloaded. This is not always possible.

I would get it level. I have weighed trailers that are unlevel having 70% or more of the weight being carried by the low axle. This is even worse in torsion axle situations.

Get it level or you will be overloading a axle, bearing, or more than likely a tire. I see it all the time.

Chris

Egon · May 17, 2012

Spend the bucks for an insert that will have the trailer level. Then use the equallizer to adjust to level when loaded.

Measure the empty truck height on the fender wells. Then try to adjust back to this height with trailer loaded. This keeps the steering geometry as it should be.

Air bags will also help make the level situation possible.

joshuabardwell · May 17, 2012

Yeah. I was afraid y'all would say that. I was hoping that just a few degrees might be acceptable, but I guess, especially if I'm going to be towing close to the trailer's capacity, even a small amount of unevenness will start to overload one axle. Doggone it.

Anybody in the market for a weight-distributing shank? :laughing:

jejeosborne · May 17, 2012

joshuabardwell said:
Yeah. I was afraid y'all would say that. I was hoping that just a few degrees might be acceptable, but I guess, especially if I'm going to be towing close to the trailer's capacity, even a small amount of unevenness will start to overload one axle. Doggone it.

Anybody in the market for a weight-distributing shank? :laughing:

Have you considered changing your axle to an overslung if it is now an underslung? It will raise your frame up about 5 inches helping from dragging but hurting the load height.

jejeosborne · May 17, 2012

[QUOTE="Egon]
Measure the empty truck height on the fender wells. Then try to adjust back to this height with trailer loaded. This keeps the steering geometry as it should be.

Air bags will also help make the level situation possible.

[/QUOTE]

I check both front and rear wheel well distances empty, then try to get equal drops front and back. Your post makes it sound as if you at only checking the rear wheels. The rear shouldn't return to the preload distance. That would be over tension condition.

joshuabardwell · May 17, 2012

jejeosborne said:
Have you considered changing your axle to an overslung if it is now an underslung? It will raise your frame up about 5 inches helping from dragging but hurting the load height.

I was under the impression that you couldn't do this, because the spring perches are either on the top or the bottom of the axle, and if you were to flip it around, it would reverse the camber of the wheels.

joshuabardwell · May 17, 2012

jejeosborne said:
I check both front and rear wheel well distances empty, then try to get equal drops front and back. Your post makes it sound as if you at only checking the rear wheels. The rear shouldn't return to the preload distance. That would be over tension condition.

100% correct. At the moment, I'm just talking about lining up the ball height with the coupler on the trailer. I haven't even started working on the WD system yet.

jejeosborne · May 17, 2012

joshuabardwell said:
I was under the impression that you couldn't do this, because the spring perches are either on the top or the bottom of the axle, and if you were to flip it around, it would reverse the camber of the wheels.

All you need are perches from your local farm or trailer store and weld them on. You can leave your old ones in place in case you want to go back. They are about $5 each. I have done this to two trailers. You are correct though, can't just flip them like the old day with the straight axles.

joshuabardwell · May 17, 2012

jejeosborne said:
All you need are perches from your local farm or trailer store and weld them on. You can leave your old ones in place in case you want to go back. They are about $5 each. I have done this to two trailers. You are correct though, can't just flip them like the old day with the straight axles.

Hmm... well, I don't have a welder, nor know how to use one, so I think I'll pass on that for the time being, but I'll keep the suggestion in mind. Even if I was to pay somebody else to do the welding for me, it'd come out cheaper in cash than a new shank, but a lot more expensive in terms of hassle and PITA moving the axle over. I think a new shank is going to be the way I go.

jejeosborne · May 17, 2012

joshuabardwell said:
Hmm... well, I don't have a welder, nor know how to use one, so I think I'll pass on that for the time being, but I'll keep the suggestion in mind. Even if I was to pay somebody else to do the welding for me, it'd come out cheaper in cash than a new shank, but a lot more expensive in terms of hassle and PITA moving the axle over. I think a new shank is going to be the way I go.

I would only "flip" the axle if you have dragging issues as I did. As far as cost, the welding would be done for about $20 at a local shop. There is only about a two inch bead of weld on each one. The new shank is definitely the easiest proper fix. You should be able to sell your old one on CL

Diamondpilot · May 17, 2012

There are lots of negatives to flipping axles to also think of. Ramp angle being the biggest issue but also brake over angle at the top of the ramps, load height, stability, wind resistance, ect.

Chris

Highbeam · May 17, 2012

Don't think of it as a few degrees off, think of it as 5" off. Depending on the truck, it may squat down a good bit when loaded but not 5" so you need to buy the proper shank.

Try to always tow with a level trailer. Obviously it is more important to have a level trailer when it is loaded vs. unloaded so being a little nose high with the empty trailer is going to happen.

I recently set up my new 8000 lb RV trailer to be towed by my F350. When putting the tongue on the ball the ball dropped 3". After snapping up the WDH spring bars it was only a 2" drop.

I had the opposite problem though, my new trailer coupler was really really tall. I had to buy the 100$ drop shank and make it a rise shank and it still barely worked.

So yes, buy the right shank. You and I will both have an extra standard shank in the barn.

Egon · May 17, 2012

jejeosborne said:
I check both front and rear wheel well distances empty, then try to get equal drops front and back. Your post makes it sound as if you at only checking the rear wheels. The rear shouldn't return to the preload distance. That would be over tension condition.

Yep, I only check the back. The levellers are tensioned to parallel with the trailer tongue and the rest is made up with the air bags.:thumbsup:

Didn't state things properly originally.

joshuabardwell · May 18, 2012

Highbeam said:
Don't think of it as a few degrees off, think of it as 5" off. Depending on the truck, it may squat down a good bit when loaded but not 5" so you need to buy the proper shank.

Indeed. I'm with you.

With the WD system set up properly, it shouldn't squat much, should it? Etrailer.com videos say maybe 1" in the back.

Try to always tow with a level trailer. Obviously it is more important to have a level trailer when it is loaded vs. unloaded so being a little nose high with the empty trailer is going to happen.

My current running theory is that if the trailer weight is less than a single axle's GAWR, then it probably doesn't matter too much.

I had the opposite problem though, my new trailer coupler was really really tall. I had to buy the 100$ drop shank and make it a rise shank and it still barely worked.

Be careful on that. I have been shopping for shanks lately, and some of them seem to be indicated as drop ONLY. I don't know what's different about them, and don't see why you couldn't flip them upside down, but I assume the manufacturer has a good reason for marking them this way.

Highbeam · May 18, 2012

joshuabardwell said:
With the WD system set up properly, it shouldn't squat much, should it? Etrailer.com videos say maybe 1" in the back.

Be careful on that. I have been shopping for shanks lately, and some of them seem to be indicated as drop ONLY. I don't know what's different about them, and don't see why you couldn't flip them upside down, but I assume the manufacturer has a good reason for marking them this way.

Depends entirely on the truck. 1000 lbs of tongue weight has a profoundly different impact on an F350 than it does on a VW pickup. My 8000 lb trailer will put 800-900 lbs of tongue weight onto my ball and gave 3" drop without WDH and 2" with WDH. I provide these data points as reference so that you can see what you should be aiming for and what to expect.

The shank I bought was from an RV store. I don't even know if it has a brand name or rating stamp on it butneither did the original and like the original, the new drop shank is indeed a solid heavy shank. Not much choice for me with this but I will keep an eye on it.

Can't imgaine why it would matter which way you flip the "grave digger" drop shank. Actually, on edit, yes I can. In my setup the ball is farther from the centerline of the receiver than it would be if the shank was flipped. So yes, the grave digger is weaker when set up as I have it vs. the down way.

joshuabardwell · May 18, 2012

Highbeam said:
Depends entirely on the truck. 1000 lbs of tongue weight has a profoundly different impact on an F350 than it does on a VW pickup. My 8000 lb trailer will put 800-900 lbs of tongue weight onto my ball and gave 3" drop without WDH and 2" with WDH. I provide these data points as reference so that you can see what you should be aiming for and what to expect.

I guess I see the point. The WD hitch will even out the drop between the front and back, but the absolute amount of drop depends on the truck's suspension and the trailer weight. The point is that the front and back should squat more or less evenly with WD (back a little more than front, IIRC).

Can't imgaine why it would matter which way you flip the "grave digger" drop shank.

I got my information from shopping around on etrailer.com. In their filter options, they had some shanks that were rated for drop only, and explicitly said that they couldn't be used in the "raise" position--at least, that's how I interpreted it.

I'm not a fabricator, but I can see how the stress on the joint would be different in the raise position than the drop position. In the raise position, the joint is trying to "open" and is "pulling" on the welds holding the reinforcement brace in. In the drop position, the joint is trying to "close" and is "pushing" on the welds. Or maybe that's just totally off-base. Like I said, I'm not a fabricator. I just do what the instructions on the box say. (Most of the time.)