Newer air ride dump trucks in rough terrain

The Kenworth AG 400/460 8 bag is good suspension on a dump truck. My boss owns 8 dump trucks that mostly make their living in the woods building and maintaining logging roads year round. 1 is extended leaf Hendrickson, 2 are Chalmers and the rest are AG 460. Guess what trucks get used the most and which ones sit when we don't need them all running. The air ride when properly spec'd out on a proper dump truck is the way to go in my opinion. A converted light framed highway truck with some cheesy 4 bag suspension ain't gonna cut it in the long run. At the end of a long day it is the difference between going home and feeling like mowing the lawn or sitting in the recliner. As far as dumping while leaning that is something that simply takes experience to know what you can get away with depending on what you are hauling and where you are dumping and suspension makes very little difference in stability when you dump the air out of the bags. That is one thing you do want to do when dumping anyway mainly so you don't ruin the shocks and shock mounts when all the weight comes off the truck at once. When you're in a cold sweat with your heart in your throat you know you are gaining valuable unforgettable experience...

dieseldog5.9 said:

The Hendrickson Extended leaf rides better empty at least. My problem with Hendrickson is the specialty tooling to change bushings. Camel back is expensive to work on, and the trunnion stand is the week link.

I take Truckshop's suggestion for Hendrickson and raise him one to the Chalmers suspension.

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For something like that it's best just to take it to a shop who does them all the time, had them done years ago on first truck and it was mind blowing how cheap they are to replace, it wouldn't be worth anyone's time trying to do them themselves, the only thing the shop did was suspension and alignments. And I mean how often is it going to be done once maybe twice in the trucks lifetime?

cuttin edge said:

A little grumpy are we?

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Not at all and it wasn't directed at you, just don't like seeing people judging something based on someone half a$$ing something and saying "it didn't work so this is garbage". Converting a road tractor to a dump truck and saying it's awful means SFA towards what the OP was asking.

Air bags have a purpose in dump trucks and have gotten so common for a reason.

The uneven dumping wouldn’t be my only concern about the air ride. Actually the main thing is getting in to spots. Backing up on fresh soft gravel when putting in new driveway, or over chunky bank run or shale. Off driveways into muddy grassy spots etc. I have a Volvo Triaxle now with double locking rears that I end up locking in frequently.

the air ride setup that would be on the international truck I was considering is Hendrickson primax or HAS.

JPV said:

The Kenworth AG 400/460 8 bag is good suspension on a dump truck. My boss owns 8 dump trucks that mostly make their living in the woods building and maintaining logging roads year round. 1 is extended leaf Hendrickson, 2 are Chalmers and the rest are AG 460. Guess what trucks get used the most and which ones sit when we don't need them all running. The air ride when properly spec'd out on a proper dump truck is the way to go in my opinion. A converted light framed highway truck with some cheesy 4 bag suspension ain't gonna cut it in the long run. At the end of a long day it is the difference between going home and feeling like mowing the lawn or sitting in the recliner. As far as dumping while leaning that is something that simply takes experience to know what you can get away with depending on what you are hauling and where you are dumping and suspension makes very little difference in stability when you dump the air out of the bags. That is one thing you do want to do when dumping anyway mainly so you don't ruin the shocks and shock mounts when all the weight comes off the truck at once. When you're in a cold sweat with your heart in your throat you know you are gaining valuable unforgettable experience...

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I always dump the suspension, but had only done it because I hate the bags snapping up like that all at once, I do the same when I drop a trailer or set the float on the ground to unload something. Never even thought of the shocks. Good point. I always compared KW 8 bag to driving on an icy road. Once you get used to it, it's fine, but the first time is strange.

suladas said:

Not at all and it wasn't directed at you, just don't like seeing people judging something based on someone half a$$ing something and saying "it didn't work so this is garbage". Converting a road tractor to a dump truck and saying it's awful means SFA towards what the OP was asking.

Air bags have a purpose in dump trucks and have gotten so common for a reason.

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I didn't figure you were mad at anyone in particular, you just seemed pi$$ed

suladas said:

[snip] ... a converted tractor on air ride isn't a good dump truck, air ride dump trucks are awful? There is a reason why they make different models of trucks, because they are made for different purposes and in no way is a tractor on air ride with a dump box thrown on the same as a factory purpose built dump truck on air ride.

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I run one tandem 44k dump truck and one 21k CDL triple axle dump trailer. I also have a Diamond C 26k CDL 40' hydraulic dovetail trailer, and I spec'd it with Hutch suspension and 60" spread. Been doing this a few years now, actually started in France about 20 years ago with a Mercedes 2031 rolloff bin tipper. What you say above is true. I'll share what I've learned.

1) Yes a converted road chassis is suboptimal for a dump truck. But it's hard to find true dumps on the used market. The guys on job sites that I see get stuck, or who are down for repairs a lot, run converted Petes and Freightliners. The frames and suspension mount points don't seem to be as heavy. They also have no left-right axle locking, so we wind up pulling them out more often on job sites. They have front-rear axle lock, but that's it. If you pitch over a little due to uneven terrain or sink in on one side, the tires on the unweighted side both spin but the heavy side does nothing. A purpose-built dump should be able to lock all four drive wheels up.

2) Nobody out here in my area of Central Texas runs air bags. I see zero at the quarries except lift axles. I will admit that I haven't looked at all the new superdumps that are showing up around here closely. But a local quarry who delivers road base to my yard bought 8 and so far all that have come here have leaf springs. Each cost $350k btw. And forget about spare tires ... there three different sizes on those fancy superdumps! Sit and wait for the expensive truck tire guys is all you could do. But I digress.

3) I don't know if bags ride better or not, but on forums I've seen many posts saying no improvement. My F550 is bagged and raising the pressure certainly does not improve the ride one iota. It rides like heck. I think air bags are a gubbmint "suggestion" to reduce wear and tear on pavement. Like most gubbmint ideas, it's probably wrong. The unsprung mass in a heavy truck is only slightly diminished by bags if at all. Subtract part of the weight of leaf springs (the part attached to the hangers), add in all the weight of a bag system, and I bet it's mostly a wash. In France we pay a mileage tax and that tax is lower if your truck is bagged...maybe that why bags became popular in the first place.

4) I run about 15 trailer owners groups on Fakebook. Let me tell you about all the bitching we hear about bags on trailers. Perhaps bags on CDL trailers are less reliable than bags on Class 8 trucks. The trailer guys love 'em ... except when they don't work, which is too often if you ask me. I need my machines to be like anvils, so I can make money and not spend every weekend wrenching.

FYI
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If your truck is rough with air ride, it is a poor air ride, or it's not set up properly. I started my driving years in a Peterbilt, and never spilled my coffee. We run 3 tri axle dump trailers, 4 tandem dump trailers, and every float trailer that I have ever been around has been air ride. The discussion was had not long ago, and many a leaf spring has been changed, but it is very rare that a bag has been replaced. It's not the way I would do it, but our trailers run hard over rough roads 5 days a week, and they are loaded heavy. 27 metric tonne or around 30 old ton for the tandem trailers, and The guys with the tri axle trailers haul around 40 or 44 for you if they can get away with it. They supply material for our asphalt plant, and materials for pipe work, and road building. Besides freezing up sometimes in fall, no issues. The wood haulers are all air ride as well, and they go off road a lot more than we do. I'm not crapping on the traditional suspension, but there is nothing wrong with air ride. It's like automatic transmissions. They are getting a lot better, and becoming more common. We have 2 identical Freight Shakers, 2 years apart. Same configuration, suspension, engine, rears. One is a 2019, and the auto is a 21. The 21 is almost 300Kgs lighter, and from what I have seen, gets lower fuel consumption.

Give me walking beam on a dump truck every time. We use our tandem more off-road than on-road so the Hendrickson walking beam is almost fool proof. Could care less how it rides down the road empty.

All the tri-axles here run walking beam type suspension, there may be an odd ball converted road tractor on air but it's rare. Tri-axles can legally haul 25 tons on state and secondary roads here so the dump truck companies know what works best for them.

We don't see concrete trucks on air-ride here either.

After thinking about it for a day or two, that truck is long gone anyway.

Never realized suspension was such a hot topic....

I know, good thing there are lots of options, something for everyone.

cuttin edge said:

Never realized suspension was such a hot topic....

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Don't start a gas vs diesel HD pickup thread...yikes!

cuttin edge said:

If your truck is rough with air ride, it is a poor air ride, or it's not set up properly. I started my driving years in a Peterbilt, and never spilled my coffee. We run 3 tri axle dump trailers, 4 tandem dump trailers, and every float trailer that I have ever been around has been air ride. The discussion was had not long ago, and many a leaf spring has been changed, but it is very rare that a bag has been replaced. It's not the way I would do it, but our trailers run hard over rough roads 5 days a week, and they are loaded heavy. 27 metric tonne or around 30 old ton for the tandem trailers, and The guys with the tri axle trailers haul around 40 or 44 for you if they can get away with it. They supply material for our asphalt plant, and materials for pipe work, and road building. Besides freezing up sometimes in fall, no issues. The wood haulers are all air ride as well, and they go off road a lot more than we do. I'm not crapping on the traditional suspension, but there is nothing wrong with air ride. It's like automatic transmissions. They are getting a lot better, and becoming more common. We have 2 identical Freight Shakers, 2 years apart. Same configuration, suspension, engine, rears. One is a 2019, and the auto is a 21. The 21 is almost 300Kgs lighter, and from what I have seen, gets lower fuel consumption.

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It's just Firestone bags over std leaf suspension. I mainly use it for a little more ride height when hauling the 40' dovetail.

Canada seems to be much different from Texas in suspension choices.

I currently have (2) dump trucks. My first ('94 Pete 377) is a converted OTR truck with Peterbilt AirLeaf. The frame was extended (so it is stiffer due to overlap across the splice) and the dump bed has a subframe. As you can imagine there is just not enough frame flexibility to keep traction when the ground requires articulation of the suspension. Loaded is no problem. Empty requires due diligence to not get stuck. It rides great down the road when empty. When loaded the air bag suspension allows more side to side sway so one must get used to that.
The other truck ('84 KW w900) has the extended leaf walking beam. In my opinion it is a great suspension when driving over rough/off-road terrain. It gets traction regardless of empty or loaded.
In my area I have seen many dump trucks (converted from OTR trucks) that employ the KW 8-bag air ride suspension. I don't know enough to be able to identify if they are AG400, 460, or what, but they do seem to get much better traction than my Pete AirLeaf does.

dieseldog5.9 said:

The Hendrickson Extended leaf rides better empty at least. My problem with Hendrickson is the specialty tooling to change bushings. Camel back is expensive to work on, and the trunnion stand is the week link.

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I think that the extended leaf walking beam is a great dump truck suspension. It's been proven over the years as well. I suppose the bushing tool can be an issue for some but there are all kinds of services available for getting this done. Many will come to you.
Sorry, I just don't quite agree with the better ride comment....Maybe when compared to Hendrickson pad. In my opinion the empty ride quality is one of the drawbacks (on the driver and the truck). Air ride cab goes a long way to remedy this.

RenoHuskerDu said:

3) I don't know if bags ride better or not, but on forums I've seen many posts saying no improvement. My F550 is bagged and raising the pressure certainly does not improve the ride one iota. It rides like heck.

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Comparing the ride quality of a spring suspension system (like that of an F550) that is supplemented with air bags, to a true air bag suspension is not quite "apples to apples". Adding air to your F550 bags will only serve to make it stiffer and, no matter how much, or little, air you have in those bags, it will never be softer than the springs.

DGODGR said:

I think that the extended leaf walking beam is a great dump truck suspension. It's been proven over the years as well. I suppose the bushing tool can be an issue for some but there are all kinds of services available for getting this done. Many will come to you.
Sorry, I just don't quite agree with the better ride comment....Maybe when compared to Hendrickson pad. In my opinion the empty ride quality is one of the drawbacks (on the driver and the truck). Air ride cab goes a long way to remedy this.

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The Hendrickson Extended leaf is different then the standard hendrickson, the top leaf is longer, so when empty you only ride on the one longer leaf rather than the standard hendrickson where you ride on the entire spring pack all the time. So load carrying capacity when loaded, smoother ride when empty.

DGODGR said:

SNIP
...there is just not enough frame flexibility to keep traction when the ground requires articulation of the suspension. Loaded is no problem. Empty requires due diligence to not get stuck.
SNIP
Comparing the ride quality of a spring suspension system (like that of an F550) that is supplemented with air bags, to a true air bag suspension is not quite "apples to apples". Adding air to your F550 bags will only serve to make it stiffer and, no matter how much, or little, air you have in those bags, it will never be softer than the springs.

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Does that Pete have locking axles, or just front/rear interlock? That's all my IH dump has, and so far I've never gotten stuck. But I've seen other guys get pitched to the side a bit, then the light side just spins while the heavy side does nothing. They have to lower the bed and wait for a machine to come pull them out. It's embarrassing.

Yeah, comparing added bags on leafs to full air is not worth much. I've never been in a full bag truck except the one I took driving classes in, and that was years ago.

RenoHuskerDu said:

Does that Pete have locking axles, or just front/rear interlock? That's all my IH dump has, and so far I've never gotten stuck.

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My Peterbilt has a diff-lock, but not full lockers.

cuttin edge said:

The M2 Freight shakers they have been buying have whatever the he double hockey sticks this is for suspension. Rides ok loaded, but bouncy empty.

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Hendrickson INTRAX and is also on Western Star I drive. Is a little icky feeling when started driving it as will side roll something fierce in corners with heavier loads. Light Weight was the selling point and as such I am not much of a believer in it other than Low Maintenance. Still will get stuck, truck has Power Divider and Lockers but once starts down will not recover. Shop I run out of runs many tubs and air ride tractors, dump the suspension and dump the load except Off Level has still done in a few.

just get a rhinestone and stud kidney belt.