You are going to have to pick a priority when deciding about the rear suspension. A 600 mile round trip is a long haul for an off road oriented suspension. I'm not sure what your states' reg's are but here you can get about 15 tons on 10 wheels (depending on tare weight-54,000 lbs max). That will be 13 or 14 600 mile trips (less if your state recognizes the 3rd or 4th axles). You can get away with an air ride suspension in a dump truck but it is not the most desirable. Many guys around here get good articulation (what an off-road suspension will do better than an on-road suspension) from the Kenworth 8 bag suspension. A truck with an off-road suspension will get better traction when operating on uneven terain. This will really only matter when the truck is empty. If you choose to get a truck with an off-road oriented suspension (ie. Hendrickson walking beam or Chalmers) get a suspended cab to help with smoothing out the road miles.
The front axle capacity will depend on the length of the truck. The shorter the wheel base the more weight transfer to the front. Many trucks can get away with a 12k# F/A. I have a Pete 377 (set back front axle) and I put an 18k# F/A under it. I feel I could have been OK with a 14k# F/A but the 18 was available when I needed it. It is important to remember that the component group will always be limited by the weakest link in the group. Put in another way an 18 or even 20k# F/A is no better than a 12k# F/A if the tires you put on it are only rated for 6k# each. The tire would then become the weaker part of the componenet group and you could not legally put more than 12,000 pounds on the axle. The F/A issue may be mutte if you are going to add the tag axles. Before you buy I would recommend that you research your states' DOT rules (especially bridge gap rules and winter restrictions). Each state has adopted it's own weight rules and the tag axles may not benefit you at all. Good luck.

 

Great advice from the post above, just wanted to mention gradeability/startability. This is all about torque and gear ratios. A converted highway truck might not have low enogh gearing to get you moving when loaded on a hill (say like in a gravel pit or mine). For off road work you need a 8LL, 9LL, 15 or 18 speed transmission.(splitter in low range/gears) Stay away from the 9,10 and 13 speeds as these are more for the highway. The general rule of thumb is spec the rear axle(s) ratio for good fuel economy and pick the transmission for the torque multiplication and low end grunt to get you moving when stopped on a hill loaded.wesport

 

I'm not even going to pretend to know alot about dump trucks. But, If you're going used, consider this. I know a couple of guys who bought road tractors and put dump bodies on them. Their reasoning is that dump trucks are generally driven by lower paid, less experienced drivers. They don't have much vested interested in the truck. This, combined with inexperience, leads to an abused truck. I do know one of them ended up putting in an 8LL. Deep reduction helps offset the highway gears, and he hates split shifting around town. So he's got the torque to to twist off his breakaway driveshaft once a year, but the truck will sail.

 

I am looking at a converted L9000 tractor, to a single axle dump. I think it has a 6 speed,with a 350 horse cummins.

It would be mostly used as a dumpster but I would like to put a plow on it and sub it to the state

how do you think it will do ?

 

Front end would be too light. Wheel base would be too short if it was a daycab.

 

Front end would be too light. Wheel base would be too short if it was a daycab.

What would you want for a front end?

 

Preferrably 20, but 18 or 16 may do. I may be wrong but most tractors have 12-14 front ends. This will be important esp if your hanging a hd plow off the front.

 

I would agree that the plow would put a lot of weight on the front end but we don't know (the poster has not said) what his F/A is rated for. He has not posted the wheel base either. There are possibly millions of 2 axle dump trucks (with plows) out there. I usually see them owned and operated by municipalities. Look at one of those to see what the F/A is rated at. Then measure the wheel base. The length will help determine how much weight is transferred to the front vs. the back. The weight in question is primarily for the load (in the bed) and not so much as the weight of, say a snow plow. The snow plow rides in front of the axle so a lot of it's weight will transfer to the F/A. Many (if not all) big truck plows are mounted with a frame that connects to the center (or sometimes the rear mount is at the back) of the truck. I would think that this helps to transfer weight to the whole truck and not just the F/A. I don't know what a big truck plow weighs but a 12k F/A may be able to handle the weight of the truck and plow as well. There are a multitude of questions that are coming up for me about your conversion. These questions are best left to a professional truck up-fitter. If you buy trucks at a dealer you may be able to get help from them. In my opinion the information can be obtained but it will be difficult at best. Once the conversion actually begins you will probably come across more issues/obstacles. I would recommend looking for a truck that is already equipped as you would like instead of making the conversion. As I have said before there are a lot of them out there and I'm sure you could get one (especially in this economy) for far less money, and far less grief, than you would spend on a conversion. This may not fit your situation but in my opinion is good advice.
Best of luck.

 

Preferrably 20, but 18 or 16 may do. I may be wrong but most tractors have 12-14 front ends. This will be important esp if your hanging a hd plow off the front.

agreed, around here most conversions have a steerable fourth axle to ease the load on the 12# FA also i have found that most conversions only have 36's or 38's for rears

 

Having just done this and having learned a lot AFTER buying it, I can tell you lots.

First, start with your state's (whatever state's you are going to run in) weight laws, that will let you know what's going on. In Colorado for example, the max a straight truck can weigh is 54,000lbs with 3 axles. All other axles are ignored. (thus, nobody runs lift axles like they do in other states). On secondary roads, the rear axles can weigh up to 40,000lbs, on the highway on straight trucks (in Colorado), you can put 36,000lbs on the rear tandems. Thus, if you want to max out, you want at least 18,000lb front ends. Start there. Heavy front ends are relatively rare, expensive and tires are insane ($700 EACH for my last set of 385's) They also don't turn very well (turning radius is limited). As someone said, probably 80% or more of the trucks out there have 12,000 lb front ends. Pay attention to bridge law. Heavier axles and ratings add weight. My truck EMPTY weighs 26,000lbs. But it has 20k fronts, 46k rears and a 20' box with a double frame. It's a beast. (much more than I really need)

2. Figure out what you are going to haul and how dense it is and how heavy it loads. If you are hauling manure (like us), your box can be light and not very strong, (because a 1 yard of manure weighs about 700lbs max, many times less). If you are hauling rip rap, you need a really strong box. (drop a 100lb rock from 10 feet above on the bottom of your box and see what it does to it). Rock boxes cost (and weigh) a lot more than grain boxes for example. How many yards box do you want to get? (and how much can you haul?). If you are hauling 1.5" rock all the time which is 1.2 tons/yard and you can legally haul 15 tons, then there isn't much point in spec'ing a 20 yard box. You'll have to do your research here. Also, Do you want a tall box and short frame or a longer box and shorter? Depends on weight laws (and bridge laws) and what you are hauling. Longer trucks ride better, but the box costs more.

3. A dump truck is a contradiction in terms and you always have to decide what you are doing more of.

• a. A dump truck is empty half the time and usually only weighs about 50,000lbs or so. Most semi's are full all the time and weigh about 80,000lbs. You'll find many dumps (from the factory) have about 350hp motors, sometimes even 11 liters or smaller. This actually works with enough gearing. Putting 500hp in a dump truck will be fun, but will kill your mileage.
• b. Off road and dumping in dirt and picking up you want a tough suspension (spring, camelback, chalmers, hendrickson). On road, empty, these all suck and you want air ride. But air ride is terrible off road and somewhat dangerous if dumping off center. Most factory dumps are a tough suspension.
• c. As someone noted, transmission matters a lot. You need a LOW first gear. Like 25:1 or better to really putter around in dirt and you run a lot uglier grades than most on road trucks. Most dumps are 8LL's or 18 speeds. (some 15 speeds split high, some split low). An 8LL is 5 low, 4 high and 5 more REALLY LOW. (and 3 reverse gears in total). it's nice to not have to shift so much. an 18 speed is 5 low, 4 high, 5 more low and 4 more high. A nice thing to have for a dump truck (wish mine had an 18). Most road tractors are 10 speeds or 13 speeds and those are all high with very little low hole. You'll tear up clutches doing a lot of off road work with a 10 or 13 speed.
• d. You want a tall suspension and tires. yes, it makes it top heavy (and BTW, dumps are really top heavy, easy to tip over), but it gives you lots of ground clearance. Ground clearance isn't an issue on the freeways, really matters off road. Easy to high center a frame on a rather small grade when you're 20 feet long. (look at an on road tractor at a truck stop, notice it's probably got 10 to 12" of clearance under the tanks, imagine going over a curb with that fully loaded, it's going to tear stuff up) .
• e. Gearing matters. See the same basic discussion on transmissions above. But remember, most dumps have 24.5's so the gearing and tires work together. Most dumps are geared pretty low (in the 4's typically) which means they run out of top speed (which is where the 18 speed helps). What kind of driving are you going to be doing? Mostly 70mph or mostly 45mph? See the problem?

4. Most dump trucks aren't very comfortable. They just aren't. They are basic and tough and not fancy. Less stuff to break, but not as nice. I'm simply worn out after a 400 mile day in the Mack, but the Freightliner I"m just getting warmed up. Decide how much it's really going to get used and go with that. Cement guys drive all day every day in mostly rather basic trucks. (with extremely tough suspensions)

5. I've been told this by more than one mechanic and in my experience I think it's a good rule of thumb. Factory dump trucks are just DONE by 400,000 miles. I wouldn't touch one at all. OTR tractors are pretty much DONE by 900,000 to 1 million miles. Dump trucks get beat to death by vibration and they get a lot more of it than OTR tractors.

6. A box is crazy expensive. Figure $25,000 or so to put a box on a tractor (plus or minus)

7. My personal experience and hard won wisdom.

• a. Do NOT buy a truck that's been sitting for a long time, everything dries out and has to be replaced.
• b. Get an engine brake. I don't care how flat it is, (and it's not flat here) not having an engine brake just blows and it's thousands to add one.
• c. Get it well and truly inspected by someone you really trust on heavy trucks. Figure any used class 8 truck needs $5000 worth of work. (you just don't know what yet)
• d. pull the ECM printout (dealer can do this, you'll have to pay), it will tell you TONS about that truck and how it was used, average mileage, etc. Newer trucks have a lot more information in their ECM
• e. If you are even thinking about pulling a trailer, make sure the truck has a pintle hitch in back and air to the back. About $2,000 to add one

Other thoughts.
Remember anything over 55,000lbs (including pulling a trailer) has to pay HVUT. (so a 50,000lb dump plus a 10 ton (20,000lb) trailer means you have to register at 70,000lbs for HVUT and probably registration. I assume you already know about USDOT, UCC, etc, etc. Doesn't Kansas have their own number? (KCC?)

If I was going to haul something 300 miles one way, I'd do it in an end dump. You get the same mileage in a dump vs road tractor, but you can haul about twice as much. 50 to 100 miles one way is about the furthest effective distance you want to go in a straight truck.

I hope that helps, feel free to PM me if you want to know more of what I've learned the hard way.

 

Great post Brian. I learned more in two minutes than I have in two years of trying to pick the brains of a couple local excavators.

I'm considering a Ford L8000. Retired state DOT truck, 6 wheel. Big highway blade (which I don't really need) and a nice wing (which I really could use, almost need) I'm not sure about the motor. One said it's a Ford, another guy said Cummins. About 250 horse. 248K on the truck, less than that on the motor. 8LL. double tilt bed with front conveyor and left side spinner.

 

I'm considering a Ford L8000. Retired state DOT truck, 6 wheel. Big highway blade (which I don't really need) and a nice wing (which I really could use, almost need) I'm not sure about the motor. One said it's a Ford, another guy said Cummins. About 250 horse. 248K on the truck, less than that on the motor. 8LL. double tilt bed with front conveyor and left side spinner.

Is this a 2 axle truck? (6 wheels?)
2 axle trucks are class 7 and are a lot smaller. Figure a lot fewer effective miles (lot smaller motor, usually a 8L or so, and that 250hp tells me the same thing). The motor should say on it what it is. At the very worst, take the last 8 of the VIN and go into the Ford big truck dealer and let them tell you about what came in the truck originally.

Big Ford's (class 8's, L9000) are going to be a real pain to get parts for in about 5 years. Sterling is what Ford used to be (Diamler bought Ford's class 8 business and rebadged them as sterlings), they are shutting Sterling down and only guaranteeing parts for 3 more years. I wouldn't buy one. BTW, in class 8 world, Fords/Sterlings have by far the biggest and most comfortable cabs. I mean it's not even close.

 

read this one,

it has a lot more info in it compared to the one above.

Well shoot, I tried to edit my original, and I got it all done and now I can't edit the original. It made another post.

Having just done this and having learned a lot AFTER buying it, I can tell you lots.

First, start with your state's (whatever state's you are going to run in) weight laws, that will let you know what's going on. In Colorado for example, the max a straight truck can weigh is 54,000lbs with 3 axles. All other axles are ignored. (thus, nobody runs lift axles like they do in other states). On secondary roads, the rear axles can weigh up to 40,000lbs, on the highway on straight trucks (in Colorado), you can put 36,000lbs on the rear tandems. Thus, if you want to max out, you want at least 18,000lb front ends. Start there. Heavy front ends are relatively rare, expensive and tires are insane ($700 EACH for my last set of 385's) They also don't turn very well (turning radius is limited). As someone said, probably 80% or more of the trucks out there have 12,000 lb front ends. Pay attention to bridge law. Heavier axles and ratings add weight. My truck EMPTY weighs 26,000lbs. But it has 20k fronts, 46k rears and a 20' box with a double frame. It's a beast. (much more than I really need)

2. Figure out what you are going to haul and how dense it is and how heavy it loads. If you are hauling manure (like us), your box can be light and not very strong, (because a 1 yard of manure weighs about 700lbs max, many times less). If you are hauling rip rap, you need a really strong box. (drop a 100lb rock from 10 feet above on the bottom of your box and see what it does to it). Rock boxes cost (and weigh) a lot more than grain boxes for example. How many yards box do you want to get? (and how much can you haul?). If you are hauling 1.5" rock all the time which is 1.2 tons/yard and you can legally haul 15 tons, then there isn't much point in spec'ing a 20 yard box. You'll have to do your research here. Also, Do you want a tall box and short frame or a longer box and shorter? Depends on weight laws (and bridge laws) and what you are hauling. Longer trucks ride better, but the box costs more.

3. A dump truck is a contradiction in terms and you always have to decide what you are doing more of.

• a. A dump truck is empty half the time and usually only weighs about 50,000lbs or so. Most semi's are full all the time and weigh about 80,000lbs. You'll find many dumps (from the factory) have about 350hp motors, sometimes even 11 liters or smaller. This actually works with enough gearing. Putting 500hp in a dump truck will be fun, but will kill your mileage. Bigger motors last longer though. I'd want at least a 12L motor and at least 350hp. Honestly, I'd probably want right around 400/425hp, which should put you in a good compromise of fuel vs power.
• b. Off road and dumping in dirt and picking up you want a tough suspension (spring, camelback, chalmers, hendrickson). On road, empty, these all suck and you want air ride. But air ride is terrible off road and somewhat dangerous if dumping off center. You also typically have to dump the air to both load and unload, otherwise you are putting a lot of pressure on the air bags. It's somewhat amazing that the big heavy dump truck will really rock when you get to 2 to 3 yards of dirt/rock dumped in it. Most factory dumps are a tough suspension.
• c. As someone noted, transmission matters a lot. You need a LOW first gear. Like 25:1 or better to really putter around in dirt and you go up and down a lot uglier grades than most on road trucks. Most dumps are 8LL's or 18 speeds. (some 15 speeds split high, some split low). An 8LL is 5 low, 4 high and 5 more REALLY LOW. (and 3 reverse gears in total). it's nice to not have to shift so much. an 18 speed is 5 low, 4 high, 5 more low and 4 more high (and 4 reverse, although you probably can't use the real high reverse). A nice thing to have for a dump truck (I wish mine had an 18). Most road tractors are 10 speeds or 13 speeds and those are all high with very little low hole. You'll tear up clutches doing a lot of off road work with a 10 or 13 speed.
• d. You want a tall suspension and tires. yes, it makes it top heavy (and BTW, dumps are really top heavy, easy to tip over), but it gives you lots of ground clearance. Ground clearance isn't an issue on the freeways, really matters off road. Easy to high center a frame on a rather small grade when you're 20 feet long. (look at an on road tractor at a truck stop, notice it's probably got 10 to 12" of clearance under the tanks, imagine going over a 6" curb with that fully loaded, it's going to tear stuff up) .
• e. Gearing matters. See the same basic discussion on transmissions above. But remember, most dumps have 24.5's so the gearing and tires work together. Most dumps are geared pretty low (in the 4's typically) which means they run out of top speed (which is where the 18 speed helps). What kind of driving are you going to be doing? Mostly 70mph or mostly 45mph? See the problem?
• f. You want it to be tough and strong to handle big heavy loads, but that makes the truck heavy (tare weight) which means you can't haul as much. It's a tough balancing act. Almost all dump trucks weigh between 20,000 and 26,000lbs or so. A lot depends on the size and strength of the box.

4. Most dump trucks aren't very comfortable. They just aren't. They are basic and tough and not fancy. Less stuff to break, but not as nice. I'm simply worn out after a 400 mile day in the Mack, but the Freightliner I"m just getting warmed up. Decide how much it's really going to get used and go with that. Cement guys drive all day every day in mostly rather basic trucks. (with extremely tough suspensions)

5. I've been told this by more than one mechanic and in my experience I think it's a good rule of thumb. Factory dump trucks are just DONE by 400,000 miles. I wouldn't touch one at all. OTR tractors are pretty much DONE by 900,000 to 1 million miles. Dump trucks get beat to death by vibration and they get a lot more of it than OTR tractors. There are a lot of trucks that go further than this, but it's a reasonable rule of thumb to be looking at. This is why a lot of OTR tractors get converted to dumps trucks. The company that bought them new retires or sells them about 500,000 miles (because for big companies, the costs outweigh the benefits), there are a LOT of trucks for sale with right around 500,000 miles on them. You buy the tractor, stretch the frame, get rid of the sleeper and put a box on it and you'll get another 250,000 miles or so out of it. But it will then be TOTALLY done. Beat to death.

6. A box is crazy expensive. Figure $25,000 or so to put a box on a tractor (plus or minus) plus 13% FET.

7. My personal experience and hard won wisdom.

• a. Do NOT buy a truck that's been sitting for a long time, everything dries out and has to be replaced.
• b. Get an engine brake. I don't care how flat it is, (and it's not flat here) not having an engine brake just blows and it's thousands to add one. By far this is my biggest mistake with the Mack.
• c. Get it well and truly inspected by someone you really trust on heavy trucks. Figure any used class 8 truck needs $5000 worth of work. (you just don't know what yet)
• d. pull the ECM printout (dealer can do this, you'll have to pay), it will tell you TONS about that truck and how it was used, average mileage, etc. Newer trucks have a lot more information in their ECM
• e. If you are even thinking about pulling a trailer, make sure the truck has a pintle hitch in back and air to the back. About $2,000 to add one
• f. The big truck business is less than ethical IMHO. Everything is "as is where is" and stuff simply doesn't work. Some of it they know and don't tell you, some of it they don't know and it takes 1000 miles of driving to shake it out. A lot of it you simply couldn't know just by driving. Have YOUR guy inspect it (I know, I already said this, but it's important) and work up an estimate to fix it. Get a dyno report, get an oil analysis. Either split the cost or make them pay. The class 8 business is SLOW right now, they'll do it. Remember a lot of things that might be wrong (esp with brakes) are not annoying things, they are big fines and out of service things on Commercial Motor Vehicles and since big trucks roll thru scales all the time, this stuff has to work, all the time.
• g. Big trucks are all customized for each truck. most people don't realize this. Every time you go to the dealer, you need the last 8 of the VIN. So take the last 8 of the VIN of any finalist truck down to the dealer and let them punch it in to their computer and they can tell you what motor/transmission/lots of stuff is in that truck. Where it was originally ordered, etc.
• h. Dealers matter. If you don't have a good dealer near you, you'll get frustrated trying to get parts and such. Make sure you have a good heavy duty shop (or the dealer, although most shops are cheaper than dealers) that you trust that can do the work you need done on it. You can't just take it to Joe the auto mechanic to get it worked on.
• i. Pre-03 motors get a lot better mileage. (20% better easy), 03-07 motors do ok and the technology is pretty solid. 07 to 2010 motors get terrible mileage and have a LOT of extra emissions stuff on them. Figure maintenance costs a lot higher for a newer truck. In 2010 yet more emissions stuff is coming which will be more expensive and "interesting" for the first year or two.

Other thoughts.
Remember anything over 55,000lbs (including pulling a trailer) has to pay HVUT (IRS form 2290, June 30th thru June 30th). (so a 50,000lb dump plus a 10 ton (20,000lb) trailer means you have to register at 70,000lbs for HVUT and probably registration. I assume you already know about USDOT, UCC, etc, etc. Doesn't Kansas have their own number? (KCC?)

If I was going to haul something 300 miles one way, I'd do it in an end dump. You get the same mileage in a dump vs road tractor, but you can haul about twice as much. 50 to 100 miles one way is about the furthest effective distance you want to go in a straight truck. Actually I don't think I'd haul much of anything 600 miles with half of that being empty. It's $1/mile to run a class 8 truck. (fuel, depreciation, maint, taxes, insurance, etc) as a reasonable rule of thumb. That's $600 PLUS your time (all day, one trip) so figure $800 to get 25 tons hauled (in an end dump). I'm sure I could find someone to do it for less and not tear up my equipment.

There are a lot of really heavy duty trucks in the midwest (michigan must have some cool weight laws), and you can usually make that work, but figure that everything, and I mean everything is going to be rusted/corroded on or together. Just add in extra money to fix things. And of course, the upper midwest is getting pounded economically, so you can drive a deal.

We haul manure out for people. Manure doesn't weigh anything (750-1000lbs/yard) so I can haul 14 tons, but I can take 28+ yards. Pretty much every other truck here in Colorado has a 15-16 yard dump box. Just having a new box built was going to be $33,000 (low bid, high bid was $46k). Figure a 500k mile tractor at 30,000, another 5,000 in work to get that running right, 5,000 to stretch the frame, now you're at 65,000/70,000 dollars for a 500,000 mile truck. We wanted to grow the business first.

My Mack originally was a Quint (5 axles), but as I said earlier the extra axles don't do any good here in Colorado, so I had them removed. It makes it excessively long, but it works. The Mack has a 20' long box, to the top of the box it's 25 yards, I can pile over it probably to 27/28 yards. The Mack was $40k. But I ended up putting almost $12,000 into it (it had a bunch of crap wrong with it that I just couldn't know) But that's still almost 20,000 cheaper than doing it the other way. And it's allowed me to prove the business for less. There was no other way to get a big box here in Colorado. I had to drive to go get it, because here it's worth not much (too big for 99% of the haulers) and thus couldn't have it checked out. Only had 243,000 miles on it when I bought it. (1999) but it's needed a lot of work. The last guy clearly wasn't doing the maintenance at the end.

I know now what I'd do differently. So, although it's not a perfect truck and we certainly went thru a lot with it I'm glad I did it this way because I probably would have spec'd it wrong and spent more money and still not had the right thing. Sometimes you just have to learn the hard way.

• The camelback suspension is BRUTAL when the truck is running unloaded on concrete (gawd I hate concrete roads) but I think I'd go tough suspension again. It's a LOT better off road and we do enough offroad to make it worthwhile. It's probably 30:1 paved to unpaved, but that last little bit is where it all comes down to what works. I think you'll see that almost all factory dumps are tough suspension, there has to be a reason.
• Mine is only a 350hp and I'd like to see a 400/425. It's pretty much a dog when full and towing a trailer. (of course it weighs 65,000 at that point).
• Out here simply too many hills to not have a jake brake/engine brake. That's the biggest thing I'd change.
• I'd put a lighter box on it but wider (I still could get more volume), although the big heavy box has allowed me to do some loads that I couldn't do in a light box. (I hauled off a few loads of concrete/trash for a guy the other day, made a couple hundred). So, again, everything is a compromise.
• I'd get a set back front axle and set the tandems forward a little bit. It would make it a lot more maneuverable without losing any weight. I have to get into some UGLY spots. (I mean 1" on either side and turning). It's got a 286" wheelbase, it could shorten 2 or 3 feet and make a big difference in getting around.
• I'd have it with a pintle and air to the back. electric brake trailers suck.
• The gearing is actually ok (4.88's), but it's done by 61mph. I'd like an 18 speed so I could overdrive the top more and maybe get a good solid 65/70mph top end out of it. But the low gearing which I thought I would hate is actually much more useful on those small portions that are off road. Maybe it could go bigger motor and 4.56's.

You simply need to figure out what YOUR application is and what YOUR weight laws are and work around that.

I hope that helps, feel free to PM me if you want to know more of what I've learned the hard way.

 

Don't be in a hurry looking for a truck wait untill you find a good one. Just a thought but have you ever though of buying a chassis and putting a hook and lift on it?