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Air Springs and WDH

Red Rider

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Is anyone using the Timber Grove Air Springs (the ones that replace the coil spring) on a Ram 2500 and is using a weight distribution hitch? If so, what procedure do you use to set up the hitch?
 

AH64ID

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It doesn’t matter what brand airbags you use, the hitch setup is the same across the board for a WDH w/ airbags.

The best way to think of it is that the WDH compensates for tongue weight and airbags compensate for additional payload in the pickup.

When you set the WDH up have an empty truck and a loaded trailer. Only minimum air in the bags. Adjust the WDH per the brand you have. This should result in some rear end squat. 1-1.5” below empty ride height is usually ideal for ride and handling.

Take note of that height. When you add additional payload inflate the bags to get back to that height. If you go higher you will reduce the effectiveness of the WDH, and reduce your ride quality and handling.

The single biggest mistake people make with airbags is inflating them to return to an empty ride height.
 

LateToTheParty

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I assume you've already seen, but Timber Grove states you don't need a WDH, but they cover the setup in case you disagree.

1669058681592.png
 

AH64ID

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I assume you've already seen, but Timber Grove states you don't need a WDH, but they cover the setup in case you disagree.

View attachment 47638

There are some pretty decent misunderstandings of a WDH and how to properly utilize airbags in that flyer, which are quite common but surprising coming from a smaller company like Timber Grove. Also using non-standard acronyms like GCVWR, it's simply GCWR.

For starters WDH's and airbags are different tools, WDH for tongue weight and airbags for standard payload. They can both be setup to work for the opposite, but that's not what they should be used for.

Additionally, you don't want to use airbags to restore the vehicle to it's empty ride height. This is a common mistake that decreases ride and handing.

Each model is slightly different, but a good starting point is to allow the rear suspension to sag 1-1.5" with the trailer hooked up. When using airbags and WDH the airbags should only be inflated enough to bring the rear height back to that 1-1.5" sag that is present with a trailer but no additional payload. Going any higher will reduce the effectiveness of the WDH and have negative effects on the ride/handling of the TV.
 

Red Rider

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Thanks for the info. Yes, I did see that in the info that came with the springs. However, air springs at any pressure will not redistribute the weight back to the front axles. All the air spring will do is raise the pivot point but when you put a considerable weight onto the trailer hitch, it will inherently pivot the weight off of the front axle. I don’t mean to disagree with Timber Grove’s statement but when you set 1500 lbs on a trailer hitch that is 5 ft behind the rear axle, physics dictates that there will be less weight on the front axle which would lighten the steering on the tow vehicle. I guess it would be OK depending on your tolerance for less steering efficiency.
 

H3LZSN1P3R

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Thanks for the info. Yes, I did see that in the info that came with the springs. However, air springs at any pressure will not redistribute the weight back to the front axles. All the air spring will do is raise the pivot point but when you put a considerable weight onto the trailer hitch, it will inherently pivot the weight off of the front axle. I don’t mean to disagree with Timber Grove’s statement but when you set 1500 lbs on a trailer hitch that is 5 ft behind the rear axle, physics dictates that there will be less weight on the front axle which would lighten the steering on the tow vehicle. I guess it would be OK depending on your tolerance for less steering efficiency.
Just for reference here is what 1625lbs on the hitch with no WDH looks like on my 19 2500 offroad pkg cummins truck any weight loss on the steering axle is minimal but you dont have the weight of a cummins over your frontend so you will loose a bit more steering weight but not very much
 

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LateToTheParty

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I don't have any experience with the air springs that completely replace the coils, but I've had multiple trucks with supplemental air bags and they've been more than sufficient for my needs. I did use a WDH a few times on my 4th gen when renting a few TTs, but that more to appease the rental facility.
 

Red Rider

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You are correct about the extra 900 or so lbs of the Cummins compared to my paltry Hemi. With my trailer hooked up without a WDH, the front end rises a little over 1 1/2 inches. Whether that is enough to seriously affect my steering is maybe up for debate but what is not debatable is the safety of me, my wife, our grand child and all the drivers around us.… I stick with the WDH.
 

jsalbre

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Just for reference here is what 1625lbs on the hitch with no WDH looks like on my 19 2500 offroad pkg cummins truck any weight loss on the steering axle is minimal but you dont have the weight of a cummins over your frontend so you will loose a bit more steering weight but not very much
I’d bet your long wheelbase with the 8’ bed makes a big difference too. That’s a lot longer of a lever.
 

AH64ID

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Just for reference here is what 1625lbs on the hitch with no WDH looks like on my 19 2500 offroad pkg cummins truck any weight loss on the steering axle is minimal but you dont have the weight of a cummins over your frontend so you will loose a bit more steering weight but not very much

Have you had that on the scale?

Approx 1400lbs of tongue weight will drop my front axle approx 400lbs with a very short shank it's a bigger weight loss if I use the normal WDH shank without the bars. It wasn't really perceptible just looking at it. I wouldn't call 400lbs huge, but I do like how it handles with the WDH better.

The Hemi and the Cummins are sprung differently, so even if the Cummins is -400lbs and heavier than a Hemi the handling can still be worse than the Hemi based on the spring rate and change is ride height.
 

H3LZSN1P3R

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Have you had that on the scale?

Approx 1400lbs of tongue weight will drop my front axle approx 400lbs with a very short shank it's a bigger weight loss if I use the normal WDH shank without the bars. It wasn't really perceptible just looking at it. I wouldn't call 400lbs huge, but I do like how it handles with the WDH better.

The Hemi and the Cummins are sprung differently, so even if the Cummins is -400lbs and heavier than a Hemi the handling can still be worse than the Hemi based on the spring rate and change is ride height.
No scales around me. The specs on the trailer said 1625 tongue weight dry so it may have been slightly more, i run a 2k tongue/20k towing rated curt adjustable hitch it was a delivery for a family member only a 2hr run down the highway (pulled beautiful at 110km/hr) …

the cummins is ~900lbs heavier than the hemi
 

Red Rider

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The looks of a truck will fool you. I can jack my rear air springs up (trailer attached but no WDH) until the truck is level but the weight on the front tires is still going to be less. Sometimes it makes me wish I had purchased the Cummins with 8’ bed so this whole WDH issue would less of an issue but then I remember how much of a pain it was parking and then there is the current price of diesel :).
 

H3LZSN1P3R

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The looks of a truck will fool you. I can jack my rear air springs up (trailer attached but no WDH) until the truck is level but the weight on the front tires is still going to be less. Sometimes it makes me wish I had purchased the Cummins with 8’ bed so this whole WDH issue would less of an issue but then I remember how much of a pain it was parking and then there is the current price of diesel :).
This was without airbags. I still dont even have my bags installed i just have had them for 8 months lol
 

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