Air bags for load management

Dave

Explorer
My truck seems to "bob" or "buck" on the highway when we have our pop up camper hitched along with the bed full of gear. It's not a violent motion and it's not to the point where it's dangerous, just uncomfortable.

The suspension sags about two inches when we're loaded, mainly from the load in the bed rather then trailer being hitched. Would air bags on the rear axle help minimize the bucking when loaded and towing?

The truck is a Nissan Frontier with stock suspension and the trailer is a Fleetwood Neon. I have not hit the scales, so I don't know what we weigh loaded.
 

njtaco

Explorer
A couple of questions...

What is the trailer weight and what is the tongue weight ready to leave on a trip?

Is the trailer top heavy, and is it level when towing?
 

xcmountain80

Expedition Leader
I use the airlift inner coil air bags and they work oh so amazing. Have them on my dads tahoe and my 4Runner.


Aaron
 

xcmountain80

Expedition Leader
I wouldn't load my 4Runner any more than I do, I hate vehicle sag when loaded. It reaaaaly hinders the mountain maneuverability.

Aaron
 

Dave

Explorer
njtaco said:
A couple of questions...

What is the trailer weight and what is the tongue weight ready to leave on a trip?

I don't have a real world number on what MY trailer weighs and I'd have to dig up the specs from the manufacturer. If I remember correctly, they had the trailer listed at around 2,000 lbs total weight with around 200 lbs tongue weight.

Like I said, I haven't been to the scales when loaded. It's something I always say I'm going to do on my next trip and never do. Next time...

njtaco said:
Is the trailer top heavy, and is it level when towing?

I don't think the trailer is top heavy and it is level when towing.

michaelgroves said:
Great piece of kit, airbags. But they can be a temptation to load up more heavily!

Yeah, I could see that. Lucky for me, I'm out of physical space too! ;)
 

njtaco

Explorer
Dave said:
I don't have a real world number on what MY trailer weighs and I'd have to dig up the specs from the manufacturer. If I remember correctly, they had the trailer listed at around 2,000 lbs total weight with around 200 lbs tongue weight.

My first thought is not enough tongue weight. Do you have the LP tank full, and a battery in front? If there is not enough tongue weight, the hitch can "unload" and cause the back of the truck to "lift" and "drop", causing the bucking sensation.

Another option of course is to upgrade the shocks.

I have air bags on my Tacoma, and while they level the truck, they don't seem to dampen the ride at all. They make it "firmer" and less comfortable, but not really in a "control the ride" way. More like "too much spring", if you know what I mean. I keep about 10 psi in them normally, and add enough air to help support a load when loaded. I have a 150 lb cap on the truck full time.

Remember that raising the air pressure in the bags to compensate for tongue weight also unloads the front of the truck, which changes steering and braking.

I hope that all made sense. :eek:

As far as brands, I prefer the Firestone over the Ride-Rite. Or whatever deal I come across, which is why I have RR on the Taco... ;)

Conversely, if you have over 250 lbs or so of tongue weight on the ball, you might consider a weight distributing hitch. Until you weigh the tongue loaded, you won't really know what you need, though.
 

spencyg

This Space For Rent
I'm going the route of airbags to control excess weight in the rear of my van. I have had airbags in previous trucks and they are most beneficial when the weight you are toting around is pushing the limits of the stock springs. I used to find this problem was indicated by bobbing around, much like if you had a very heavy mass on the roof. It sounds like this is the problem you're experiencing, and I say go for the bags....

Spence
 

Dave

Explorer
njtaco said:
My first thought is not enough tongue weight. Do you have the LP tank full, and a battery in front? If there is not enough tongue weight, the hitch can "unload" and cause the back of the truck to "lift" and "drop", causing the bucking sensation.

I do have a full 20lb propane tank, the trailer's spare tire, and a 50 pound battery on the tongue. I always thought one of the primary symptoms of not enough tongue weight would be trailer sway, which I'm not experiencing.

njtaco said:
Remember that raising the air pressure in the bags to compensate for tongue weight also unloads the front of the truck, which changes steering and braking.

This I don't follow. I would think that raising the air pressure with the truck loaded would load the front suspension since you are putting the truck back to level. Am I misunderstanding something?
 

tommudd

Explorer
Dave said:
I do have a full 20lb propane tank, the trailer's spare tire, and a 50 pound battery on the tongue. I always thought one of the primary symptoms of not enough tongue weight would be trailer sway, which I'm not experiencing.



This I don't follow. I would think that raising the air pressure with the truck loaded would load the front suspension since you are putting the truck back to level. Am I misunderstanding something?


What he is referring to is ...well a tetter - totter ( or how ever you spell it) effect raising the air pressure in the bags in the rear will give you an effect of being on a tetter-totter..... trying for a better way to explain, but its not working this A.M. LOL I know what he is referring to and have experienced it before as well

Tom
 

njtaco

Explorer
tommudd said:
What he is referring to is ...well a tetter - totter ( or how ever you spell it) effect raising the air pressure in the bags in the rear will give you an effect of being on a tetter-totter..... trying for a better way to explain, but its not working this A.M. LOL I know what he is referring to and have experienced it before as well

Tom

Exactly...

Picture a teeter totter in balance...if you raise the fulcrum/pivot point, both the teeter end and the totter end go up too. :) How much either end goes up on a truck depends on where the center of mass (weight) is in relation to the centerline of the axle. This includes the tongue weight of the trailer, BTW.

Inflating the bags on an empty truck does not usually have this effect, because the mass is so far forward of the axle.
 

Dave

Explorer
I get what you're saying about the teeter totter effect, but wouldn't most of the weight of the truck still be forward of the axle?

Tongue weight of my trailer is ~170 pounds. Based on manufacturer specs, plus the lp tank and the battery, I would estimate my trailer to weigh around 1100 pounds total.
 

monele

Adventurer
Also Check out Timbren SES systems (progressive rubber springs) that fit in place of your bump stops (in the coil or above the leaf) and take on the roll of both bump stop and sag relief. Have them on the back of my LJ as an alternative to extended bump stops that were too hard. Best suspension upgrade I've made. Call these guys for the best price:

Burke Spring and Alignment
Terre Haute IN
www.burkespring.com

866-556-9197
 

michaelgroves

Explorer
njtaco said:
Exactly...

Picture a teeter totter in balance...if you raise the fulcrum/pivot point, both the teeter end and the totter end go up too. :) How much either end goes up on a truck depends on where the center of mass (weight) is in relation to the centerline of the axle. This includes the tongue weight of the trailer, BTW.

I have to say I still don't get why this would be a significant effect. Using your teeter-totter analogy, the rear axle is the fulcrum, but the t-t is not in balance (the "teeter" front wheels are on the ground, while the "totter" towing ball is up in the air). Raising the fulcrum of a t-t when one side is heavier than the other doesn't lift both sides, nor does it change the balance ratio (apart from some cosine effect when the t-t angle is extreme).

What I will concede is that too much tongue weight will make the front end and steering lighter than it should be, and that airbags won't cure that problem in the slightest. But I can't see them making it worse.
 
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