Truck suspensions

[DKinWA]

What are the pros and cons to air suspensions on dumptrucks? I've been looking off and on for awhile now and found a 1994 Kenworth W900 that looks to be in good shape and in the price range I can afford. The only downside if there is one would be the air suspension. I'd really like to understand the differences, but I'm not finding much with my google searches.

 

[Woodstock]

We have two Kenworths T800 1991 models. It seams like every other year or two we are having to put new bushing in between the axels. We have also broke the piece comming down between the axels off the frame that keep the axles in line and connects them to the truck a few times. Our trucks go off road a lot to. I thank if you can keep them on the road more they will be alright. It takes a little while to get used to the air suspention when loaded heavy, it likes to rock a little and lean going around corners. You just hug the seat a few times you'll get used to it. This is just what I have experienced. Hope it helps. We just bought an 04 Pete with drop axle. Both are good trucks.

 

[Lashlander]

A company we work with now and then have a T800 with an air suspention and the guy says he'll never own another. Like Woodstock says its tippy. I know they have to dump the air out of it everytime they dump it. He also said ya had to be careful because it would get stuck on the crown of the road. I personally never drove the truck but have no reason to doubt him. We bought a T800 a while back and had them change the suspention from an airbag to a Hendrickson spring. I think the Chalmers is the best one out now. IMHO.

 

[tylermckee]

i live in the same area and what ive heard from truck drivers is that the air suspension is just fine working mostly on the road but doesnt do as well offroad. Last place i worked for had a pete with air bags and it was used offroad a lot and was always breaking something. It had also been on its side once from not dumping the bags and dumping rock on a slight sidehill.

 

[Dwan Hall]

One of the machanics here said that you need to seperate the sides and make them independent each with there own acuater (sp) so the side with the most weight will inflate it keeps them from tipping over. Stock there is 1 senser to inflate both sides and there lies the problem causing them to tip. ( the heavy side causes air to crosover to the light side raising it higher causing the tipover.
I drove one of there trucks, a converter OTR Mack with air and it was a pleasure to drive and there was no need to dump the air before raising the box even on a slight side hill.
I personaly have hendrickson on all 3 of my trucks. but hear the same about chalmers been the best.

 

[nedly05]

you need dual leveling valves,that helps some. look for an 8 bag or go spring :my2c

 

[nedly05]

This the AG-400 8 bag suspension from kenworth, they released it in 2003, supposed to increase roll-resistance and add side stability!

 

[woberlin]

About the only dump trucks with air-ride around here are those hauling asphalt or bulk materials that do not go offroad. All the excavators and independent truckers hauling construction material have spring or walking beam suspensions. The last job I was on, a guy with air-ride brought a load of gravel for the driveway-he had to dump the airbags before he backed in, and went about 10 feet before being bogged down in the mud. He said his next truck won't have air bags. I don't know about the new 8 bag systems, they look like they may be alot better.

 

[jperfect]

i know here in michigan 90% of the trucks short doubles graveltrains all have air ride with no problems. and dont have to dump the air. the one that i drive scaled out at a 150000 lbs and i never had to dump the air, i was always offroading.

 

[woberlin]

Jperfect, how many axles are you running on a truck grossing #150,000, and what kind of terrain and off road conditions do you have there. I'm just guessing, but I'd think a truck trailer combo with 12 or 13 axles would have to pretty stable no matter what type of suspension. I'd also bet that it is very flat where you are with very sandy soil. Quite a different situation than a tandem axle in hilly terrain and muddy clay!

 

[thejdman04]

I love air, wouldnt ahve it any other way, yeah they roll more but you get used to it. Dump the suspension and dump it. Once you go air you wont go back, keeps the truck from rattling apart.

 

[jimmyjack]

the two petes we have are air ride ,its nice on the road and on hard gravel but off road you need to lock the rears and the axles to keep moving on uneven or slick ground. my truck is on springs (walking beams) rides ok, rides a lot better loaded but no problems in the mud or uneven ground.
as for dumping the bags, the guys who drive the two petes do it before dumping, they say if you don't when you dump the truck the load comes off faster than the bags can adjust and they will over inflate and may pop:beatsme thats what they say , i wouldn't what to be the one to try it ok with that said if you work mostly on hard surfaces than i'd go with air , if not than it maybe more of a pain in the butt

 

[CM1995]

:my2c

I think the answer is like any machine - depends on the application. Walking beam is the best for a construction truck that is going to spend 20-30% of its time off-road. The other 70-80% of the time the dump is running inner city not over the road. The ride is important but you need the ability of a walking beam off-road. If I was running asphalt, dense grade or contract hauling primarily on the road I would go with air ride for two reasons: ride quality and it is easier on the truck.

Also most of your used dumps with air-ride are over the road trucks converted to dumps. Over the road trucks are spec'd different than construction trucks. The trans., gearing, suspension, ect are usually not as heavy spec'd as a construction truck. This could be contributing to the problems some folks have with air ride dumptrucks.

 

[DKinWA]

I talked to a couple of folks yesterday (one driver and their truck mechanic) and they echo much of what's been said here. Considering much of the time I'm on pavement or good gravel, the smoother suspension sounds pretty good to me. My off road work is really limited to small new home sites and that doesn't last long once I start spreading gravel. I guess I won't write off the air rides yet Anyway, thanks for the information and discussion.

 

[tylermckee]

I guess i should add that the pete at my old work actually held up alright considering i had seen air under the tires on it a few times Moving brush around on site and they couldnt drive threw the mud so they tried flying over it

 

[jperfect]

Jperfect, how many axles are you running on a truck grossing #150,000, and what kind of terrain and off road conditions do you have there. I'm just guessing, but I'd think a truck trailer combo with 12 or 13 axles would have to pretty stable no matter what type of suspension. I'd also bet that it is very flat where you are with very sandy soil. Quite a different situation than a tandem axle in hilly terrain and muddy clay!

we have a lot of mud right now, but we have alot of clay, sand, rock. the area that i live in is pretty hilly. we are only aloud 11 axles. this trucks go all over job sites. tring to find some pics.

 

[Bob Horrell]

My Western Star tri-axle has Chalmers and I like it a lot. With an air ride cab and the air ride seat, it isn't too bad unloaded (although not near as nice as air ride suspension). It rides real smooth loaded. I do go off road a lot and that is where it shines. I hardly ever have to engage both axles. When one set of tires is pushed up, it drives the other tires into the ground. My buddy with the air ride Pete is always engaging his especially when empty just to get out of a jobsite. Also, there is very little that goes wrong with the Chalmers - cheap to run. And it is lighter than springs and therefor allows for more payload.
I would say the same as the others on this thread. If most of the driving is on road, go with air ride. If a fair portion is off road, go with Hendrickson or Chalmers. I have also heard that the Volvo/Autocar spring ride is very smooth and also good for off road. It is, however, expensive to run/fix etc.

 

[CM1995]

I have also heard that the Volvo/Autocar spring ride is very smooth and also good for off road. It is, however, expensive to run/fix etc.

Hey Bob-
Is that spring ride suspension you are referring to the T-Ride ( I think that is what it is called.) I was just wondering- looking at a Volvo VHD for a tri-axle and I don't know that much about them although they look like good trucks.

 

[Bob Horrell]

The T-Ride is it. I run into a guy from time to time that has a fleet of dump trucks (Pete, Kenworth, and one Autocar). The Autocar has the T-Ride and he is always driving it. He could drive any of the other trucks but says the T-Ride is the best riding truck he has and that's why he uses it. If you look at one you will notice it looks different than most other spring suspensions.

 

[CM1995]

The T-ride looks like it could handle the 46K rear ends that are under some of them. I am use to seeing Chalmers or Hendrison (sp?) just didn't know much about the T-ride.