Frame Differences

[csb4435]

Just a quick and easy question for you.  I was reading chassis dimensions and differences on chuckschevytrucks.com and was wondering if all 1/2, 3/4, and 1 ton frames are the same for, say, a 1985?  Is the "only" difference the length?  The frame isn't any beefier just because it's a 3/4 or 1 ton is it?  The reason I want to know this is because I want to build up a short bed (81-87) truck with a heavy drivetrain and want the best frame possible.  Bottom line...if I cut down a 1 ton frame to a short bed length, is that the same as just having a short bed 1/2 frame?  Thanks

[Blazin]

I have heard they are different and I have heard they are not different. Bottom line is if they are diferent it would not be worth the effort etc. in all the work of shortening the frame. You would not gain anything from it. Even if the short bed frame is a bit lighter your going to be in the same boat with a frame that has been cut in half and a section removed.

Edited by: Blazin at: 4/10/07 11:11 am

[GMCTed]

I have an 85 3/4 ton pickup. when i put 1 ton axles on it i took them off an 86 1 ton pickup and the frame difference is huge. i have a friend with a 1/2 ton and the framerails are tiny compared to my 3/4 ton and the 1 ton is even bigger. but as far as i can tell the only difference in size is on the back half of the frame, from the back of the cab to the front looks similar i could be wrong about that but the back half is definitely bigger.

[csb4435]

That is the exact reason for my question.  My dad had a 1/2 ton short bed and swapped in 1-ton axles and a 454 in his 82, and when he "gassed" it hard on a good traction surface, the front of the bed would "nick" the back of the cab.  I figured a 1-ton frame would prevent any movement.  Thanks for the reply.

Colt

[xtremjeepn]

1/2 and 3/4 have a 6" thick frame under the cab. 1 ton has an 8" thick frame under the cab. (I have both, both 4x4s).

Cutting and splicing a frame is can be just as strong if not stronger than the original piece if done right. It is done all the time.  My 1 ton Crew Cab has been shortened 24" to accomodate a short box.

[Blazin]

I went out and measured all three yestarday. My K10 & K20 are 6" and my K30 is 8" as extreme stated. I agree that if done correctly a spliced frame is fine. I help my buddy shorten & lengthen Pete's, KWs, Western Stars, etc. on a regular bassis. My personal opinion is for a pickup its not worth the extra effort for the end result. I would put the effort into gusseting the short bed frame, less work and less technical labor.

[xtremjeepn]

Which part are you saying is not worth the extra effort? The splicing/shortening/lengthening or swapping to the 1 ton frame?

[Blazin]

First off it sounds as if it is assumed that the back end can be cut off to achieve this.
 Quote " Bottom line...if I cut down a 1 ton frame to a short bed length, "
Maybe this is not the case, but that is what it sounds like when I read it.
Second off If it were me and I was facing sectioning a frame or reinforcing one for more stiffness I would reinforce one before sectioning one. Less work due to the fact you can reinforce one with out having to use a jig make sure its square etc. I have been doing auto body and fabrication for 20 years and like I said in my previous post I work with a buddy often shortening or lengthening big rigs. These are not as critical as far as tight tolerances, and we still have to take extra precautions to keep them strait and square.hey are not as critical as the rear suspensions have adjustment in them. They are also allot easier as they have a strait frame both vertical and horizontally. Unlike a pickup frame that has different hight, & width sections plus different angle and bends.

[xtremjeepn]

This is the best picture I have of the Crew at the moment since we are right in the middle of building it.  The frame was shortened 24". 16" from the middle and 8" off the back to fit the short box.

[Blazin]

I can see in your case it was unavoidable as the crew cab was not offered in a short bed configuration. But for the sake of building a regular cab short bed I don't think this would be the best course of action.

[xtremjeepn]

I guess the real question would be what are the plans for the truck?

Heavy towning/wheeling/load hauling might be a good case for the 8" frame. I really highly doubt that the shortbox pickup would see the kind of abuse that the 6" frame with some work could not handle.

Of course he could do what some of the wheelers do. Chop off the back of the long box so that you keep the wheelbase but end up with a short box and a better approach/departure angle.