View Full Version : Dump truck questions

06-16-2006, 09:25 AM
Who uses converted road tractors for dump trucks. I heard they have problems with the frame breaking if they dont have a double frame. What is your experience with them?


06-16-2006, 09:31 AM
Old company i used to work for had one, it was a nice truck, never gave us any problems associated with being converted. Except for maybe the time when it got laid over on its side. We were dumping a load of big rocks, on a slight side hill, and the box broke off and went over taking the truck with it. That was the company that did the conversions fault, i think they decided it was crappy welding that caused the failure. Other than that it was a good truck, i know a few guys around here run them without problems. I could see if the truck is going to be doing a lot of offroading and really get beat up you might want a true dumptruck, but for most peoples needs i think you would be fine. Just make sure you go to a reputable company that does good work.

06-16-2006, 10:15 AM
The problem with doing this is the gearing USUALLY is'nt right.Over the road has a hiway gear,dump trucks need a lower ratio to pull more weight,especially on startup out of a pit.Around here,usually the conversion is done at the trucking companies yard which leaves a lot to be desired.They might know how to weld but never seem to place enough sheer plates.That's what might have happened in Tylers story.After 32 years raising dump bodies,dumping on any kind of side hill still scares the hell out of me.I'll pull 3' wheelies in my hoe like a walk in the park,but don't care for that.And double frame is a must unless you're hauling marshmallows.

06-16-2006, 10:26 AM
I agree with Tuney. Guy up the road bought a used OTR truck to make logging truck. Nothing but trouble. Dont know how many reends he blew but it was several. I think he must of had it regeard becuase it isn't brokedown like it was. Which was often.

Ford LT-9000
06-16-2006, 06:37 PM
The problems with converted road tractors.

1) Front and rear axles too light
2) Air ride suspension the worse POS for a dump truck
3) Front axle too light
4) Light single frame will bend behind the cab
5) Axle gearing too tall
6) Wrong transmissions a 10spd isn't good
7) Wheel base is usually too short
8) Road tractors usually have high mileage

The reason why dealers convert truck tractors to dumps is to get rid of the truck. The market is flooded with used truck tractors if you see a dump truck forsale and it says unused box its a sign the truck is a conversion stay away from it.

You don't need a double frame a heavy single frame with inserts is good enough for general use. Most double frames are the same thickness as a heavy single frame. Unless your doing some heavy offroading or you have a heavy concentrated constant load on the truck then you should have double frame.

For rear suspension you can go with spring or the rubber spring type suspension like Tuff Trac or Chalmers stay away from the air ride it doesn't belong on a dump truck. For drive axle it should be minimum 44,000lb you can get away with 40,000lb if you never leave pavement 99% of the new dumps now come standard with 46,000lb rears with locks.

Front axle minimum 16,000lbs for us out here thats minimum you really need a 20,000lb front axle a 12,000lb front axle is too light.

As for brand its what ever you like the basic economy truck in todays market is Sterlings L-9500 or the Freighliner FL series. International also builds a ecomomy dump with heavy spec's. Then you get into the better trucks like the Mack Granite, Kenworth T-800 and C-500, Western Star 4900 Series, Freightliner Severe service.

The new Mack Granites are nice looking trucks and they still have Mack's toughness. My other choice would be a KW T-800 they are hard to find and are a little pricey. I do like the old A Model W-900 KWs the best they are really hard to find now but they are tough as nails

06-19-2006, 10:49 PM
Like I said before--always double frame or if specing new,they have some single frames with the psi of the steel heavier than a double.Sooner or later EVERYONE overloads a dump truck and it's important to have that beef when you need it.Most converted tractors are junk around here.

06-20-2006, 12:14 AM
Do OTR trucks have differential locks at all? I'd be worried about that as well, I was doing some off road driving a water truck during a job about a month ago and the truck had the ability to lock up the front and second rear axle. Without those locks, I would have gotten stuck.

Ford LT-9000
06-20-2006, 02:21 AM
Yes OTR truck tractors come with diff lockers usually its only one axle where as vocational trucks have double locks. Most older trucks have open diffs its only the newer trucks that have lockers.

The problem you will have with a converted over the road tractor is they have 40,000lb rears you get into anything soft with a loaded truck and lock the diff you can blow the diff real easy.

If you got diff locks you should be running 46,000lb axles even 44,000lbs will break if you have lockers. The rule of thumb if you loaded and the wheels are spinning stop before you break something. If the truck is bouncing stop immediatly your definatly going to break something. When its jumping it means the tires are skipping and grabbing that is very very hard on diffs.

With a empty truck is not so bad but a loaded truck you can usually say good bye diff.

06-21-2006, 08:37 AM
2) Air ride suspension the worse POS for a dump truck

For whatever reason, I see lots of guys here in Western PA running air-ride on their tri-axles, and I'm talking about true dumptrucks, not converted road tractors.


Ford LT-9000
06-21-2006, 02:13 PM
A dump truck with air ride is too unstable get on some twisty roads or rough conditions you will see why air ride isn't good. I seen a air ride tridrive dump make a turn onto another road with a loaded box the whole truck healed over to one side. It was holy **** a regular tandem axle on springs doesn't do that.

You forget to dump the bags before you dump over the truck goes you will be on your side before you know it.

You get a suspension like Hendrickson Haul Maxx it will give you the ride you want and the stability of walking beam suspension.

Orchard Ex
06-21-2006, 05:05 PM
Not saying one way or the other is right, but I know that air ride is the way most all the new dumps are coming form the factory out here. Everything from singles to quints. About a dozen new Pete's at the dealer all had air ride suspensions. Lots of the Internationals had it too. One of the magazines articles I read (don't remember which mag) said that everything would be air ride soon and most manufacturers either have or were coming out with "active" air ride to counteract the leaning tendency. You are right about dumping the bags before the load but I figured there could be an interconnect switch for the forgetful.

Ford LT-9000
06-21-2006, 07:20 PM
If you want air bags then you go with a system like what these guys build click on the link then you go to their page then click on air link rear tandem.


07-06-2006, 12:19 PM
My new T-800 has the new Hendrickson HN suspension and I could not delieve the ride it gives. I havent got the bed on yet and its been my expieriance that the empty ride was worse but this thing feels like air with the capacity for heavy haul and great stability.