Rear suspension swap-Hendrickson Haulmaax/HN Series Rear Suspension

[DGODGR]

I am seriously considering replacing the rear end in my dump truck. It is currently equipped with Pete Air Leaf (low). I am looking for a used "take-out" that is better suited for off-road but will still yield a decent ride on pavement. My current ruck has had the frame stretched (so it has a sleeve) and the dump bed has a sub-frame on it too. The suspension does not articulate very well, and when coupled with the lack of flex, through the frame, it makes traction suffer when empty or pulling loaded equipment trailers up gravel road grades. Most driving is local rural mountain roads. Nearest freeway is +/- 3hours. Will carry up to 54,000# gross (legally anyway). Often pull tri-axle trailer (loaded trailer weight up to 62,000# but usually +/- 54,000#).
I was thinking Chalmers but, so far, I have only been able to locate a Hendrickson HN (not sure if it's 402 or 462). I've been to Hendrickson's site and they also call it a Haulmaax suspension. I have no experience with this suspension.
Does anyone have any experience with this suspension? I would like to know:
Does this suspension articulate well?
How well is it holding up?
How does it ride over the road?
What should I look for when previewing?
Weak points?
Pros and cons?
Overall impression?

Lastly, I am also considering getting different gearing (maybe a little lower). The truck currently has 3.90s in it (10 spd. trans, 22.5 tires), and it will run to about 80 MPH (I've driven it to CA a couple of times). It seems as though I can get 3.90s, or 4.33s in the new rear take-out. I'm not sure if I want to go as low as 4.33. I was thinking that 4.11s might be better. Thoughts?

 

[525isx]

haulmaxx has good articulation,(similar to chalmers or rubber block ) would be a good choice. I myself haul logs in the pnw (wa. state) and have used pete air trac for the last twenty years without problems. air trac has more flex than air leaf. cannot speak to ride, or durability of the hendrickson myself.

currently run an 18 speed with 3.70 and 22.5s regularly haul 105,500. I would think 4.11 should be slow enough. once again,can't speak to the ten speed, only the 18

ISX

 

[ValleyFirewood]

Do you have a decent seat in the truck?

My dumptruck has a Hendrickson RT (leaf sprung walking beam) with a double frame. I use it for logging/hauling firewood so it gets used off road quite a bit.

Empty it's a bit rough but loaded it's not bad. I've run on logging roads that were nicer to drive in the dumptruck with a load than in my 3/4 ton pickup. It flexes well too. I wish I had photos, but I've had it crossed up where I thought for sure I'd have some tires off the ground but they weren't.

The air leaf setup is a decent ride, but doesn't have a ton of flex. Everyone I can think of around here that runs a truck mostly off road (logging mostly) has some sort of walking beam setup.


Not sure on the gearing, all depends on engine power, trans and normal load.

My truck has Eaton axles with 7.17 gears and a 5/4 trans. In high gear 65 mph is around 3700rpm. (redline of 4000)

 

[DGODGR]

Thanks for the replies so far. I have done some research and the 4.33s will give me a top speed of 79 MPH. As it sits right now it tops out at 87.7 MPH. I think that will be acceptable. The only reservations I have with that is not knowing how the MPGs will be effected (5-6 mpg currently). As far as the ride goes I am considering adding air bags to the cab (about $1k ). I'll probably try it out before springing for that.

Anybody have any input on the questions related to the suspension itself?

 

[wilko]

I pulled off a KW 8 bag and installed a HaulMax when I built my dump truck. It's very stable for spreading, rides okay. It doesn't articulate, when empty, as well as an old fashioned walking beam, though. The rubber "springs" that the walking beam rides on need some load to work right.
If I were doing it over I'd look at the Hendrickson AR2 or Raydan setup.

 

[Dualie]

I had Primaxx on my T-800 heavy haul even with a 22K front axle and heavy rears on 195" wheel base it rode damn decent. It had full locking rears but i can only think of four or five times i had to engage anything more than the inter axle dif lock. One time in completely un compacted fill with an empty lowbed and a couple were starting out on slick wet hills with a load to far back on the wagon.

Granted this was NOT a dump truck but i had ZERO complaints. Your going to have have to really shop around for the right cut off with those specs though. Most of the time you're going to find run of the mill 8 bag (wouldn't recommend at all) or air leaf, or whatever freightliner calls their air ride. being in the PNW might help you as the amount of trucks spec'ed for logging and in the junk yards is going to be greater

 

[DGODGR]

wilko,
I will check out the Raydan and AR2 (both look like walking beam under airbags) but I am looking to get something as a cut off vs buying new. Maybe I should get a quote for new suspension only.
Dualie,
From what I can see, the Primaax looks a lot like the Pete air leaf. The Haulmaax looks very different to me. No airbags at all. Just rubber blocks to absorb impacts. Now that I look closer at it the Haulmaax is similar but NOT the same as the HN series. The cut-off that I am looking at has an HN series suspension. You reminded me of a very important item. I have not even asked about lockers on the cut-off I'm looking at.
The main reason I'm looking at a new rear end is because of traction issues (empty truck by itself or pulling loaded trailer). Maybe I should look at getting full locking axles, to be installed with my existing suspension, as an option.

 

[toomuchtime]

I have the haulmax 460 suspension on my dump truck. I love it. Has great articulation and is awesome offroad. On road the ride is not rougher the then my air ride pete.

 

[wilko]

DGODGR, if you spend a lot of time in this truck it's worth it in the long run to spend extra to get something that will be comfortable and perform on the job. Don't limit yourself to what you can find used, get the quote on new stuff. The worst that can happen is you spill your coffee when you see the numbers.

 

[wilko]

I always hear people bragging up their Chalmers suspension, always thought it looked awfully complicated but didn't know anything about it. Today I drove a truck with it and you couldn't pay me enough to run that. Ooof!

 

[525isx]

I always hear people bragging up their Chalmers suspension, always thought it looked awfully complicated but didn't know anything about it. Today I drove a truck with it and you couldn't pay me enough to run that. Ooof!

When the chalmers started showing up in logging trucks around here, a friend of mine said " it looks like something built in a high school ag shop" !!

ISX