Level With Me

[Benbill]

How important is it for my 40 foot Montana to be level as it travels down the highway? While I can’t tell you how many inches higher the front of the trailer is than the back it is noticeable when you look at the rig attached to the truck. My 5er is currently in for service, and when I asked the service writer about the issue he said it wasn’t a problem, but I’m not sure I believe that he is very knowledgeable on the subject, so I open it up to my forum friends for your opinion. I do have one more level of adjustment left on the pin box to lower the trailer if needed. Thank you.

[bobbecky]

You need about 6 inches between the bed rails and the bottom of the fifth wheel. Anything less and you will be damaging the truck and the trailer. It’s better to tow nose up than too close to the truck bed rails.

[Fishsizzle]

Originally Posted by Benbill

How important is it for my 40 foot Montana to be level as it travels down the highway? While I can’t tell you how many inches higher the front of the trailer is than the back it is noticeable when you look at the rig attached to the truck. My 5er is currently in for service, and when I asked the service writer about the issue he said it wasn’t a problem, but I’m not sure I believe that he is very knowledgeable on the subject, so I open it up to my forum friends for your opinion. I do have one more level of adjustment left on the pin box to lower the trailer if needed. Thank you.

How’s your headlights shooting?

[LHaven]

It's more important for the short term to keep the bedrail clearance than have the trailer level. For the long term, it's desirable to level the trailer, if only to keep your butt end from bumping up graded driveways. The most common solution is to have someone flip the springs on the trailer suspension.

[Mikendebbie]

In a recent similar thread from the Montana Owners forum titled “Clearance” a poster stated that for every 1” of height that the rig is out of level - it adds 400 lbs of load to the rear tires (for example if the front is high)...which makes sense to me. When the rig is level - all four tires share the load equally.

[flybouy]

Originally Posted by Mikendebbie

In a recent similar thread from the Montana Owners forum titled “Clearance” a poster stated that for every 1” of height that the rig is out of level - it adds 400 lbs of load to the rear tires (for example if the front is high)...which makes sense to me. When the rig is level - all four tires share the load equally.

I'd like to see the math on that claim.

[Mikendebbie]

Yeah I agree - not sure about the exact weight number that is transferred - but I agree with the concept of weight transfer.

[notanlines]

I also would like to see some proof of the 1" 400 pounds statement. Not even close would be my opinion.

[flybouy]

Originally Posted by Mikendebbie

Yeah I agree - not sure about the exact weight number that is transferred - but I agree with the concept of weight transfer.

I will find out later this spring. I have a tongue scale that I use when loading the camper. I've always measured it at level, no reason to do otherwise. So I'll try it at different heights but one thing I'll guarantee you from common sense and that's it will not make a 400 lb./inch difference and here's why. I typically end up with about 1,100 lbs tongue wt. I know, if I raise the tongue 2.75 inches higher than level it won't become weightless.

Any calculation to realize what the actual effect would have to include length from end of fulcrum (hitch) to the other end point (axels ), a LOT of math on the transference of weight between the 2 axle's, and then figure out the static loads from the "live" loads (liquids that shift in a non baffled tank).

That math is beyond my education so I'd defer to a NASA engineer.

[ChuckS]

Quite frankly I’m more concerned with bedrail clearance. I have plenty and am level.. and with the stock factory height of the new trucks coming out many are gonna find it impossible to be perfectly level.. one or two inches of above level just isn’t worth my time to think about

[Rocketsled]

Originally Posted by Mikendebbie

In a recent similar thread from the Montana Owners forum titled “Clearance” a poster stated that for every 1” of height that the rig is out of level - it adds 400 lbs of load to the rear tires (for example if the front is high)...which makes sense to me. When the rig is level - all four tires share the load equally.

While I can't vouch for the numbers, I can vouch for the alignment.

Speaking purely from a Physics standpoint, a level trailer in a panic stop situation won't change the contact patch of the rear wheels of the TV like a trailer will that's pointing upwards.

In Statics and dynamics, you create a Free Body Diagram with all the forces in and out of the thing you're interested in, a trailer that's too high will impart a vertical force at the hitch. How much? I dunno. Enough to make Bad Things Happen? I dunno...wouldn't want to find out the hard way.

Besides, random people you will never meet will silently judge you.

[Fishsizzle]

Get a bigger truck, big savings in the long run

[flybouy]

Originally Posted by Rocketsled

While I can't vouch for the numbers, I can vouch for the alignment.

Speaking purely from a Physics standpoint, a level trailer in a panic stop situation won't change the contact patch of the rear wheels of the TV like a trailer will that's pointing upwards.

In Statics and dynamics, you create a Free Body Diagram with all the forces in and out of the thing you're interested in, a trailer that's too high will impart a vertical force at the hitch. How much? I dunno. Enough to make Bad Things Happen? I dunno...wouldn't want to find out the hard way.

Besides, random people you will never meet will silently judge you.

I'd like to see the math on that to!
The red section is only true IF the weight of the tounge is substatially reduced so back to that "mythical" 1" + -400 lbs. For the black bolded section define "to high".

[dutchmensport]

I have always heard and understood (and I'm 65 years old), that a trailer with tandem axles should be as level as possible. If either nose is low or high, the difference puts extra force on the one axle and diminished on the other. Over time, one wears more than the other. Over time, one set of tires wears more than the other.

Now, the 1 inch = 400 pounds, I don't know about that. Does that apply to a 41 foot long fifth wheel, or a 35 foot long fifth wheel? And? How much does the fifth wheel weigh anyway? And exactly where is the pivot point on the trailer. The same trailer with an axle positioned 6 inches different can add a tremendous amount of weight to it, or reduce it. Remember, a portion of the camper's total weight is on the pin-box too.

But still, this does not change the information I received almost 50 years ago. If the trailer is not level, it causes more wear and tear on one axle over the other over a period of time.

[Rocketsled]

Originally Posted by flybouy

I'd like to see the math on that to!
The red section is only true IF the weight of the tounge is substatially reduced so back to that "mythical" 1" + -400 lbs. For the black bolded section define "to high".

I know _I_ can't do it theoretically, there's a lot of variables with how much braking is performed by the trailer, but all things being equal, you wouldn't want a vertical component added by the trailer.

That said, it would only be an issue if it were more than the systems involved could handle..if there's enough dampening, and tire patch, and braking, and brake proportioning, it might not be a big deal...but we've all seen the video:

https://www.youtube.com/watch?v=fWd8ml9mFMo

[flybouy]

Originally Posted by Rocketsled

I know _I_ can't do it theoretically, there's a lot of variables with how much braking is performed by the trailer, but all things being equal, you wouldn't want a vertical component added by the trailer.

That said, it would only be an issue if it were more than the systems involved could handle..if there's enough dampening, and tire patch, and braking, and brake proportioning, it might not be a big deal...but we've all seen the video:

Yes that's a good example of how weight loading makes a difference. If you look at the proportional differences they are showing they are not making "minor adjustments". It's for demonstrative purposed so they are showing an extreme difference and it has absolutely nothing to do with the "downward force" of the hitch, or the coefficient of friction from the tires to surface. It has everything to do with weight on the far end of the pivot point (the hitch) acting as a pendulum. This is elementary school science not rocket science.

I fully agree that the "ideal" is to get the trailer level. But such claims that moving the front by 1" will move 400 lbs. is respectfully ludacris. On a fiver proper be clearance must come first obviously and then leveling the trailer would be a goal. It's all about common sense and not taking anything to the extreme by passing on bad info.

[LewisB]

I certainly agree with the general comments regarding shifting weight. But I'm not sure I agree with post #14 which states,

"I have always heard and understood (and I'm 65 years old), that a trailer with tandem axles should be as level as possible. If either nose is low or high, the difference puts extra force on the one axle and diminished on the other. Over time, one wears more than the other. Over time, one set of tires wears more than the other.".

Consideration must be given to the role of tandem (or multi) axle equalizers in the suspension system. Many of the comments regarding shifting weight fore/aft seem to suggest there is a specific "ratio" - as if both axles were directly bolted (both ends) to the frame. I've always thought that the role of the center equizer in multiple axle systems was to allow both the load and road shocks to automatically be shifted from one axle to the other. For example, when traversing a pot-hole, as one tire drops down in the pot hole the equalizer automatically sifts load to the other axle - the end result is a smoother ride.

So it seems to me like two axles with a typical center equalizer mount would "tend" to operate as a single axle. So raising or lowering the front of the trailer might not significantly impact the load on any single axle in the system.

That's what I've always thought but may be all wrong.

[JRTJH]

Lewis,

You're not wrong. The equalizer functions to do "exactly that" (equalize) the forces between the two axles, or the three axles in that situation. There is a lot of "discussion" regarding "improved equalizers, CRE 3000/4000 systems, Lippert's new Road Armor" suspension, and their "competition"...

If, as you suggest, the axles were "hung with no interaction" then lifting the front of the trailer would "pivot weight" to the rear axle and lowering the front would "pivot weight" to the front axle. The equalizer "equalizes" much of that height difference to minimize the extremes.

Granted, there is "some" weight transfer, but because of the "equalizer/equalizing" components, that weight transfer is not a "static shift" based on a "linear formula"..... That "novel concept" can be easily demonstrated by laying on the ground next to your axles, have someone raise the front of the trailer 12" and monitor the equalizer angle. It will change, relative to the "weight shift" as the trailer attitude changes. That's "equalization" at work.....

[Canonman]

Thanks John,
Exactly what I thought too. I'm just to simple minded to put it into words. Basically, the equalizer puts the pivot point between the two axels?

[NH_Bulldog]

I have only ever been concerned with being close to level (If not slightly nose down) with a bumper-tow trailer. Any 5er or gooseneck I have towed has never been much of a second thought.