View Full Version : truck folks..........weight distribution, thoughts?
12-08-2006, 08:56 PM
So I've got the cab and chasis of a '02 Intl 4300 26k GVW. The wheelbase is 254" and the cab to center of axle is about 200".
Originally the truck had a 24' box on the back so the frame extends well beyond the rear axle.
Note: I'm modeling my truck after ETWMAN & WALTERO with the box behind the cab and then the Switch-N-Go system after that.
ETWMAN & WALTERO both have 4' wide boxes behind the cab and then the 14' bed behind that. That setup requires cutting the frame just after the rear axle.
I've got the extra frame there and I could put it to use.
Instead of a 4' wide box I COULD put a 5' possibly 6' wide box behind the cab. That would be "super awsome" storage capability.
That causes the Switch-N-Go system to be pused further back. I am concerned with being able to carry as much weight due to possibly overloading the rear axle while not even reaching GVW. Also just the thought of having the weight that much further back and wondering about effects on handling. Then again, it is just a foot or maybe 2 feet further back.
Truck originally designed with weight back there............hence the 24' box BUT that weight was spread over a 24' distnace. My dump body is 14' and my drop box is 15' so the weight is more contained.
This is a logically a potential issue but am I just thinking too much physics?:hammerhead:
12-08-2006, 09:03 PM
As for a hitch I guess I would be screwed? I don't know if one could be fabricated some way to reach that far and not be weak..........idk
12-08-2006, 09:35 PM
Torch the frame off right behind the rear springs shackles. Don't leave any extra frame hanging over the back. I'm serious about this too. The switch-n-go is a dead lift system. The more weight the rear axle can absorb when lifting the better you'll be. The guys at Buck's Fab will tell you the exact same thing. You don't want to run the risk of bending a frame that's hanging over. A 26k GVW is usually not a double re-inforced frame and can't take the weight (15k) in dead lift situation if its overhanging. A 4' box is plenty, you won't need anymore. I can give you the connection to the guy who made ours and walters, he did a great job. Whatever can't go in there can go in the dump body. Get a fold down side body first.
Not too mention the thing will ride horribly.
Kiss a good hitch setup good bye if you leave that frame on there too.
12-08-2006, 10:00 PM
Good point on the lifting with extended frame.
With your cut frame did you have to do anything particular for a trailer setup? My concern is that the tongue on my trailers may be too short.
12-09-2006, 07:19 AM
It should work fine for pulling a trailer. With any trailer you have to watch jacknifing but we haven't had a problem. I think we have 5' tonques on our trailers.
Northertool.com on those boxes. I think the most they had was 6' which was plenty long for us.
12-09-2006, 04:36 PM
etwman has already answered it for you chop those frame tails off and have a tow apron made for the back. If you had too much overhang on the back you possibly could seesaw on the rear axle the front wheels lift off the ground pulling on a heavy box. That would be one hell of a ride if your on any kind of slope the front of the truck would swing side to side like a dogs tail.
As etwman said the switch and go is like a dead lift system there is no rail tails to take the weight as the box is being pulled onto the truck. You may want to install some timbrens to keep the rear from squatting when pulling on a box.
For more storage on the truck you can have a toolbox behind the cab and some tool boxes on the side of the trucks frame.
When dad and I used to haul derlict vehicals dads 1 ton truck was set up like a oil field truck it had a winch deck on it with a roller type tail. Pulling on a heavy old land yacht the front wheels would bounce off the ground. The truck only had a 8000lb winch but it had enough power to see saw the truck on the rear axle pulling a heavy load over the back.
12-09-2006, 07:01 PM
I started looking into the timbrens a couple weeks ago.......you're right and I like the idea. I'll run it as is for a while but I'm sure in the near future I will install them.
As for the front of the truck lifting I know of a story where a guy driv'n a tri-axle roll off lifted a container that was full to the top with concrete.......you could almost walk under the front of the truck. He pulled it on, the front came down and he woo hoo'd and he haw'd on down the road!
For the underbody boxes........Northern Tool has dropped to a 60" but at Tractor Supply Co. I found 87" boxes "on sale" for $448 each.....diamond plate too so I'm sure I'll be going with them.
12-09-2006, 07:30 PM
Go with all aluminum tool boxes I don't know if you live in the rust belt but we found those steel toolboxes use under truck decks get rust into them pretty quickly.
Even look into having a local metal fabrication shop build you a behind the cab tool bin. They can build you what ever you need to fit your needs.
12-09-2006, 11:24 PM
Isn't the diamond plate polished aluminum? Thats what I'm going for.......no steel.
-The same as etwman's trucks..........the box (diamond plate probably) behind the cab I'm hav'n fabricated. One thing different is my box's construction. The door is actually going to be the ramp and the floor will be heavy grade mesh for easy cleaning/fall through.........1/4" size holes.
12-10-2006, 07:13 AM
Be careful with that. That was my original idea was a big fold down door. The only kicker is when your in tight areas there's no room to fold down a huge door. Its alot easier to have the ramp in under your box and slide it out when you need it. Plus you can actually take it off and use it on the site if need be. To open two 24" swing doors is alot easier and quicker.
Our floors in both boxes are mesh grate so we can wash them and have stuff fall through for cleaning.
I'm telling you, unless you have some awesome cheap fabricator have the guy that made Walters and mine make one for you. He's reasonable, one man operation, very good welder, and has made three now so he has all the notes and has worked the flaws out. Its a bolt on box so it can be manufactured without your truck even being there. Come up for the day when its done and set it on, bolt it fast.
It's totally up to you though. I just know how many things we changed on the first one to finally get it where we wanted to and strength wise as well. The frame on these big trucks flex because they are designed too. You have to take that into account when streghening these boxes with gussets in the right places or the thing won't last a week.
Just some things to think about.
12-10-2006, 01:43 PM
The box will be bolted to the frame.......Walter told me about welds popping from the frame flexing.
Do you have any up close pictures or anything of your boxes??? I'm wanting to get it fabricated back home as everything else is being done there (VA/NC border). I've spoken with a couple fabricators back home, its a matter of getting them some details and moving forward with how best construct the box. That way when the SNG arrives the truck will be ready to have it installed.
12-10-2006, 02:44 PM
When you bolt the behind the cab box on it should be mounted with U bolts the truck should never twist that much to be breaking welds on the truck body you add to the truck. The switch and go probably mounts with tabs that bolt to the cheek of the frame on the truck.
12-10-2006, 03:23 PM
It was only the welds on the top corners of the boxes that popped because the truck frame does flex a little, its supposed too. Alluminum does not do well under enormous stress and flex, once we re-inforced it, and the gussets were placed in the right spots, the problems were solved. We bolted it right to the truck frame in some existing holes and it worked fine.
As far as the plans for them I don't have them in my possession. The welder has the plans and I'm not too sure he's ready to part with them since he's now done three of them. I wouldn't be surprised if in time he put a patent on it. We've spent enough time on it considering costs, strength, and useful space that I'd have to say its pretty close to as perfect as its going to get.
I'd do this if you want too. Get a preliminary cost as to what yours is going to cost to manufacture and then call him. I'd be willing to bet that he'll be cheaper even after you come get it on a little trailer. I think Walter would agree he does a pretty nice job for the buck. He drove three hours for his.
Its kind of like the SNG system. Yeah sure you could find someone to Mickey Mouse one together and might save a couple bucks. But I've always been an advocate of when someone has spent the time, money, and research to perfect something, and it works great, its worth just buying one. You'll end up kicking yourself later because you either tried to save a buck, you didn't have all the info to do it right, or you spend countless hours attempting to fix it to make it work right. Time is money, there are some corners that can be cut and others you shouldn't. Guys that have never made one of these boxes are most likely going to highball the price because there are to many unknowns. It's not just a basic 2x6 box. We bought our second one for cheaper than our first one because it took less time to make. I bet Walters was the cheapest one yet.
I understand that you want to stay local for fabrication, and if this were the first box I would say definitely because you're going to have issues. But I feel pretty confident that the welder here has got ours down right by this point.
Not trying to be bullish here, just adding my two cents. Do what you wish.
12-10-2006, 04:28 PM
What is his contact information?
12-10-2006, 07:37 PM
I would follow the advice that ETWMAN is giving. I am very happy with my results and I don't think that I would be this happy without his help.
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