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Dual airbags for dump truck suspensions- Needed?

Alaska · 2014-04-09 13:51

Hello, We are working on spec. out our new plow trucks and have an air ride suspension option. I know we need to dump the air bags whenever we dump but the question of dual air bag levelers has come up. Do we need to have dual air bag levelers to help prevent tipping trucks over while dumping? Even if we do not "need" them, would it help to prevent tip over? Another reason I feel we need dual levelers is because in the winter these trucks will have right hand mounted wings and tend to not ride level with this configuration. Wings are taken off during the summer of course. Thank you for any input you may have.

Replies33
  1. #1JDOFMEMI2014-04-09 19:04

    My heavy haul has dual levelers, and in my opinion it is the only way to go. The truck is much more stable than others I have been around with single levelers. I think it would be cheap insurance for a dump. I also have a single axle water truck with air bags and a single leveler, and I can't believe it has not been tipped over yet. It really rolls, and has no stability at all.

  2. #2wilko2014-04-09 20:03

    Dual airbags=the driver and his passenger.

  3. #3willie592014-04-09 20:35

    Single leveling valves only work well for over the road trucks going straight down the highway. In any vocational truck with dual air bags, no way would I use single leveling valves. And much like the water truck that JDOFMEMI mentioned, I once worked on a KW T600 tandem axle, all air bag, single leveling valve fuel tank truck, was just like he mentioned, drove like a ship on waves. I fitted fast acting dual valves, the customer was astonished at the difference in the way the truck handled.

  4. #4td25c2014-04-09 21:05

    My Kenworth wrecker has the dual leveling valves . As mentioned it's pretty stable . I also plumed it up so it has two dump switches on the dash . One for the left side and the other for the right hand side . This allows me to dump one side independently to help level the truck on a hillside .

  5. #5grandpa2014-04-09 21:40

    A couple of my snowplow trucks have just one air bag on the right side of the steering axle to counter the weight of the wing on that side of the truck.

  6. #6Alaska2014-04-09 22:31

    Thank you everyone for the quick and thorough feedback! This was my first post on this forum and I see now I found a good one. We are getting Mack trucks with the Primaax suspension. There is discussion back and forth about the merits of dual levelers. I am on the side of dual levelers. For the relatively low cost to add this feature it might pay for it'self real quick. Thanks again.

  7. #7lumberjack2014-04-09 22:41

    What is the downside to dual levelers? If cost is the only downside, on a new truck, that seems exceedingly inconsequential.

  8. #8Andrew_D2014-04-09 22:49

    Our old tandem grain truck (L9000) has a single leveling valve. When the air-engaged PTO is activated, it automatically dumps the air in the suspension. A neighbour's grain truck doesn't dump the air and the first time I used it, I couldn't figure out what was going on! I thought that truck was going to tip over until I noticed that the bags weren't deflated. Found the dump valve and all was well! My KW W900 highway tractor has dual leveling valves and I will agree that it is very stable. Andrew

  9. #9BAD5oh2014-04-13 20:47

    Can you tell me more about a fast acting dual valve and a link or where I could get one? We have a 05 KW T300 single axle dump. It was a former road tractor and has air suspension. There is a single lever to dump the bags when dumping. Of course you need to take Dramamine when it's loaded. A couple of local suspension shops told me there was no solution to the rocking feeling. Would this dual valve get rid of that problem? Also could I still use the single dump valve already in the dash or does it require a second switch?

  10. #10willie592014-04-13 21:18

    Does it have a single leveling valve? Or currently fitted with dual leveling valves?

  11. #11Andrew_D2014-04-13 22:44

    My KW that I mentioned above has seperate leveling valves but 1 common dump valve in the cab. Also has 2 seperate air gauges in the cab - Left and Right. Andrew

  12. #12BAD5oh2014-04-14 05:54

    Single leveling valve. Hendrixson suspension

  13. #13willie592014-04-14 20:06

    Ok. Well, if you currently have a single leveling valve on you air bag drive axle, it baffles me why the local suspension shops told you there's no solution for the rocking motion. Granted, being air bag suspension, you won't get every bit of the rocking out of it, but I can guarantee you if you install dual fast reacting leveling valves, you'll get a noticeable difference. Like I said, the truck I did this to was a tandem axle T600 with a fuel transport tank, not only high center of gravity, but liquid. It blew the drivers mind how much different that truck drove. That was many moons ago, I can't recall the leveling valves I installed, but I went to the local Truck Pro, asked them to provide me with two fast reacting valves and they fixed me up. It's best to take the old valve with you so you can compare how the new valve is ported compared to the old valve, and you also need to check the dump line. Have the lever on the dash is the suspension inflated position (driving) and see if the dump line at the leveling valve has air pressure on it or not in that position.

  14. #14Jimmy4502022-11-10 20:06

    Willie59 do you have a part number for the leveling valves you used I have 2 standard ones but they react too slowly

  15. #15Jimmy4502022-11-10 20:08

    Also I have half inch lines running to each airbag should I downsides to 1/4 or 3/8 ?

  16. #16Coaldust2022-11-11 00:40

    Interesting discussion. It’s best practice in my world to convert tankers to a single leveling valve. A bag failure can create enough product surge to toss a rig into the ditch. The KW upfitter guide even recommends a single valve for tankers. I don’t have data to prove single leveling valves are safer. It’s just a best practice that has stuck around. Lots of tradition in the tank biz.

  17. #17Truck Shop2022-11-11 03:12

    ^^^^^

  18. #18cfherrman2022-11-11 07:34

    I've driven lots of overweight tankers with air suspension and never thought they rocked too much, but they are typically always full or empty.

  19. #19Jimmy4502022-11-11 09:33

    Well I have a 8 bag dump truck

  20. #20Jimmy4502022-11-11 09:34

    And it will rock you 2 sleep

  21. #21Jimmy4502022-11-11 09:36

    It had one single valve mounted in the center of the rear of the truck I had to add timberland blocks to help stabilize that drop Now I keep hearing about these new trucks having 2 leveling valves and not having any rocking issues so I'm just trying to find the correct valves

  22. #22Jimmy4502022-11-11 09:39

    https://zips.com/parts-detail/timbren-rear-axle-ses-suspension-upgrade-kwrag100

  23. #23cfherrman2022-11-11 13:26

    That fing sucks, be careful bud, dangerous suspension.

  24. #24JaredV2022-11-11 20:25

    QUOTE="Jimmy450, post: 1085358, member: 128881"]Well I have a 8 bag dump truck[/QUOTE] Is it the old 8 bag from the 80s and 90s? The newer suspension is plenty stable for a dump truck with a single valve. We upgraded an '84 B-model to AG460 and added a drop axle. It handles 15 tons way better now than it used to with 12 tons. But I get it's a whole lot cheaper to mess with valves than swap an entire suspension.

  25. #25Truck Shop2022-11-11 21:17

    AG100.

  26. #26Jimmy4502022-11-12 20:54

    My truck is a 2005

  27. #27Jimmy4502022-11-12 20:55

    And i sometime put 18/19 tons in it

  28. #28Jimmy4502022-11-12 20:57
  29. #29Jimmy4502022-11-12 21:03

    Ag 100 I was told not to upgrade the suspension unless I was going to Swap it out to a Walking beam suspension

  30. #30Jimmy4502022-11-12 21:09

    May try some fatter airbags I have some Pete trucks here with some pretty big air bags maybe I'll try them

  31. #31JaredV2022-11-12 23:10

    Thanks Truck Shop, couldn't remember. Yep, it's gonna be floppy. I have my doubts different airbags are going to help because the lower sway bars or torque arms or whatever they're called are still gonna be too limber and those are what keep the truck upright. I used to be a die hard walking beam guy because the few airbag (8 bag) dump trucks I was around were terrible and the walking beams I had driven were solid except for the ride. Then my boss started buying trucks with AG400/460 suspensions, put me in one and in a few days I was a believer. Unless you're doing some pretty hardcore off road hauling, I wouldn't be afraid of airbags as long as it's a good suspension for the job. There's probably better air rides for dump trucks out there, but the KW stuff is what I have experience with.

  32. #32Truck Shop2022-11-13 06:53

    There is a thing called pinion angle factory designed/built into every air ride suspension.

  33. #33DMiller2022-11-18 15:51

    Already liking all but the repair labor on my AG460 suspension.