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Dual airbags for dump truck suspensions- Needed?

A

Alaska

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Apr 9, 2014
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5
Location
Alaska, fairbanks
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.
 
JDOFMEMI

JDOFMEMI

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Jan 3, 2007
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SoCal
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.
 
willie59

willie59

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Knoxville TN
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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.
 
td25c

td25c

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indiana
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 .
 
G

grandpa

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northern minnesota
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.
 
A

Alaska

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Apr 9, 2014
Messages
5
Location
Alaska, fairbanks
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.
 
L

lumberjack

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Dec 24, 2011
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Location
Columbus, MS
What is the downside to dual levelers? If cost is the only downside, on a new truck, that seems exceedingly inconsequential.
 
A

Andrew_D

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Oct 20, 2012
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298
Location
Newdale, Manitoba, Canada
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
 
B

BAD5oh

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Apr 2, 2009
Messages
76
Location
Woburn, MA
willie59 said:
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.
Click to expand...

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?
 
willie59

willie59

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Does it have a single leveling valve? Or currently fitted with dual leveling valves?
 
willie59

willie59

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BAD5oh said:
Single leveling valve. Hendrixson suspension
Click to expand...

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.
 
Coaldust

Coaldust

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North of the 60
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Cargo Tanks, ULSD, RUG, Methanol, LPG
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.
 
cfherrman

cfherrman

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Jun 3, 2022
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Hays, Kansas
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.
 
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