New (used) IH 7500 Dump Truck purchase, modification & fix up

[mrmikey]

Overhand should be same as I am thinking of shortening C/A and frame both by 2 feet

Yup, I misread your post and thought you wanted to shorten up the overhang.
I still think I'd wait till you get the body tho, as the saying goes, s++t happens and if your luck is like mine.....

 

[Hay Dude]

So I need to figure out what to do with shortening frame and dump body overhang.

Is there a “rule of thumb” for overhang of dump box past truck frame so it won’t hit the tow hitch?
Can a 12’ box fit and dump correctly on a 10.5’ of frame, etc.?

We got the frame blasted, primed & painting finished.

Now I have to find a dump body. The existing frame from back of cab to end is 12’. The last 12-18” of frame has enough rust that I feel it needs to be cut off. If I’m only left with 11’ or 10.5’ of frame, whats my max dump body length?

Seems like 11’ dump would be perfect, but need to be open to 10’ or 12’ if a great deal comes along. Really prefer 11 or 12 to 10. So much more room/capacity.

 

[Rustyiron]

I'd be patient for a 11' or 12' and leave the axle alone and pay an additional $1000 for the right body just to not fool with moving it and the can of worms the it might open.

 

[mrmikey]

It's been awhile since I've actually mounted a single axle (retired for 2 years, worked for purchasing for the previous 5) so don't quote me verbatim .
I'd say the frame length you have now is perfect for a 12' body, the single axle configuration (CA) not so much . If you do go with a 12', you're going to have to watch your front axle weight, it'll be so easy to overload it.
We used to mount the body 12" or so from the spill plate to the center of the hinge. Any more than that, you're possibly getting into issues clashing with the pintle and the also of the body hanging up if you're spreading and try to lower the body if you're not empty.
Another thing to keep in mind if your body has too much overhang is to watch that you don't end up with the dump cylinder hitting the bottom edge of the body when the cylinders extended.

Looking at the pic, you don't have enough to cut 12-18" off the end, you'd be into the rear spring perch or is it an optical illusion? If you find a body that would work with the frame as is, is there a way you could reinforce the end of the frame? A doubler perhaps that can go a couple of feet forward to catch the rear perch bolts, I would assume there is a cross member there which would be a PIA to remove and shorten?
What did you say your CA is now?
Found this online if it helps any:

 

[aczlan]

It's been awhile since I've actually mounted a single axle (retired for 2 years, worked for purchasing for the previous 5) so don't quote me verbatim .
I'd say the frame length you have now is perfect for a 12' body, the single axle configuration (CA) not so much . If you do go with a 12', you're going to have to watch your front axle weight, it'll be so easy to overload it.
We used to mount the body 12" or so from the spill plate to the center of the hinge. Any more than that, you're possibly getting into issues clashing with the pintle and the also of the body hanging up if you're spreading and try to lower the body if you're not empty.
Another thing to keep in mind if your body has too much overhang is to watch that you don't end up with the dump cylinder hitting the bottom edge of the body when the cylinders extended.

Looking at the pic, you don't have enough to cut 12-18" off the end, you'd be into the rear spring perch or is it an optical illusion? If you find a body that would work with the frame as is, is there a way you could reinforce the end of the frame? A doubler perhaps that can go a couple of feet forward to catch the rear perch bolts, I would assume there is a cross member there which would be a PIA to remove and shorten?
What did you say your CA is now?
Found this online if it helps any:
View attachment 785720

From earlier he currently has 144" of frame and 108" CA, that sheet would seem to suggest that he should really have a 2nd axle under a 12' box and he could lose 6" CA.

Aaron Z

 

[Hay Dude]

My C/A is 108” (9 feet). I would have to slide the rear axle forward to get rid of the last 12-18” of frame because the rear hangers are on that last 12-18” of frame that is in bad shape.
The rear spring hangers on the back of the frame were left full of asphalt for many years, trapping water in them. One spring hanger has a fist sized thin area. No problem to replace. The other side rear spring hanger was full of asphalt and caused the frame to rust almost all the way through the outer frame to the inner frame.

My thinking was to slide the rear axle forward enough to a healthy steel spot (probably 12-18” forward).
This might still allow a 12 or 11’ body, but I am not 100% sure. If I have 11’ of frame (132”), I would think a 12’ bed would still be ok. Now if I shorten the frame to 10.5’ (126”) I am not positive a 12’ bed would work as I would have 18” of dump body overhang.
I have seen 11’ beds, but they are usually found on lighter contractor style dump trucks.
I need a “high walled” dump body with 32”-48” sides.

BTW front axle rating is 16,000lbs, so pretty strong up front.

I had not thought of possibly reinforcing the last few feet of frame onto the rear……not sure if it’s enough.

 

[mrmikey]

that sheet would seem to suggest that he should really have a 2nd axle under a 12' box

That's what I was eluding to in the previous post without coming out and actually saying it .
This is what I was thinking (I think my math is right, it's beer o'clock) for an 11' body allowing 10" behind the cab and a 12" overhang. Means you'd be cutting 14" or so off the end of the chassis and moving it ahead 14". I still think an 11' box is big for a single axle tho and you'd be better going 10' but I understand your train of thought also.

 

[Hay Dude]

Excellent, thanks. I forgot about the 10” behind the cab needed for clearance
A longer, higher bed is preferable for the times I’m carrying lighter bulky materials like wood chips or mushroom soil.
I believe the axle ratings Rear 30K and front 16K should ensure the truck has the strength, brakes, tires for holding the load.
I won’t be filling the box with 14 tons of rocks, well maybe once in a while lol
Sounds like an 11’ would be my favorite or 10’ a more realistic alternative

What I now need to do is figure if 96” C/A is ok for a 10 or 11?

Then there’s also the 3rd option of reinforcing the last 3-4’ and staying with 12 lol

 

[mrmikey]

What I now need to do is figure if 96” C/A is ok for a 10 or 11?

NP.
What I've got drawn (CA of 94") I figured for an 11' body, shorten the dimensions up by 12"and you'd be ok for a 10'. There's places you can cheat a bit too, the overhang and the clearance behind the cab. On the last item, make sure you leave enough room for the cylinder cradle, it's a b**ch when you have to work sideways with one hand.

Excellent, thanks. I forgot about the 10” behind the cab needed for clearance

Been there, done that, kinda sucks big time when you go to mount the body. End up getting called all kinds of not nice names and that's by me not to mention the guys working with me.

Then there’s also the 3rd option of reinforcing the last 3-4’ and staying with 12 lol

Ever been called stubborn? (meant with the utmost respect) LOL

 

[4570Man]

I have a 14ft bed on 12-6’ of frame. I don’t particularly like how much it sticks off. It makes it hard to pull a trailer and not cut into it. The axel center is 9ft from the cab.