Fabricating simple yet effective 4x4 "mud truck" frame

[Blmpkn]

Has anyone built their own frame for such a rig? Not mud truck dedicated I guess.. but more a general purpose off road fun buggy.

I have enough of a 65 chevy truck body I want to do something with. I'm thinking that fabbing a 4x4 leaf sprung frame for it would be cool.

I think making the thing as long as a two door wrangler would be neat.. the body I have is a stepside.. so putting the stepside flares right behind the cab and having just enough bedspace for a spare tire and a toolbox would be the plan and look pretty neat I suppose.

Using two straight sticks of 2x4 or 2x5 rectangle for the rails was my original idea.. but would limit articulation. Now I'm thinking that sectioning/stacking/overlapping the frame like terribly pictured below would be better, and simple to do.




I'm sorry about the quality lol, I hope you get the idea. This would be as seen from the side.

Keeping the frame sections straight greatly simplifies things for me.. simple&cheap would be the theme behind the whole project really. I'm not looking to build a super capable competition winning rig here... just something to have fun in on the weekends.

Input?

 

[Curious Hound]

If the frame you have is in good condition, my recommendation would be to shorten it and maybe box it in for extra strength. I don't think I would go as short as a 2 door Jeep, though. That.length seems to get into stability issues. But for mudding, maybe it would be ok.

 

[Roert42]

If you’re worried about the frame not flexing enough when fully boxed I would just go with c channel or something instead of reinventing the wheel.

 

[dvdswan]

Be sure to have completely flat/square surface to build the frame on. You don't want the truck to be tweaked before it hits the road or worse dog track.

 

[Eddo Rogue]

I would start with a frame. It is much easier to build it aligned and square in the end, and a major time and money saver. New good steel ain't cheap. Chevy S-10 frames are highly sought after by custom and lowrider guys, because they are flat and easy to build of off/modify. Maybe you can score one and modify it to your liking.

 

[Blmpkn]

If the frame you have is in good condition, my recommendation would be to shorten it and maybe box it in for extra strength. I don't think I would go as short as a 2 door Jeep, though. That.length seems to get into stability issues. But for mudding, maybe it would be ok.

The frame its on is pretty roached unfortunately. It really only has a couple real rot spots that need patching but I'm sure if I hit it all with a needle scaler it would end up about half as thick as it was leaving the factory lol.

Be sure to have completely flat/square surface to build the frame on. You don't want the truck to be tweaked before it hits the road or worse dog track.

Buying a big long level and some of those screw style jack stands would definitely happen before the acquisition of steel.

I would start with a frame. It is much easier to build it aligned and square in the end, and a major time and money saver. New good steel ain't cheap. Chevy S-10 frames are highly sought after by custom and lowrider guys, because they are flat and easy to build of off/modify. Maybe you can score one and modify it to your liking.

I had considered just snagging a rolling squarebody frame to modify, but the fact that I'd be shortening it so much, along with a bunch of other crap leads me to the belief that it would be a good bit quicker/easier to make my own.

Plus, I'd feel bad taking a nice squarebody frame for a vehicle that won't see the road again.. I'd rather leave it for someone doing a resto or something.

If you’re worried about the frame not flexing enough when fully boxed I would just go with c channel or something instead of reinventing the wheel.

Is not enough frame flex a thing for off road rigs? I always figured you'd want to be as stiff as possible

 

[Eddo Rogue]

The frame its on is pretty roached unfortunately. It really only has a couple real rot spots that need patching but I'm sure if I hit it all with a needle scaler it would end up about half as thick as it was leaving the factory lol.



Buying a big long level and some of those screw style jack stands would definitely happen before the acquisition of steel.



I had considered just snagging a rolling squarebody frame to modify, but the fact that I'd be shortening it so much, along with a bunch of other crap leads me to the belief that it would be a good bit quicker/easier to make my own.

Plus, I'd feel bad taking a nice squarebody frame for a vehicle that won't see the road again.. I'd rather leave it for someone doing a resto or something.



Is not enough frame flex a thing for off road rigs? I always figured you'd want to be as stiff as possible

Flex is good. This is why I prefer chromoly steel over aluminum for bike frames. Steel flexes flexes, aluminum does not, it snaps....carbon fiber even more so.

 

[Blmpkn]

Flex is good. This is why I prefer chromoly steel over aluminum for bike frames. Steel flexes flexes, aluminum does not, it snaps....carbon fiber even more so.

What do you ride for bikes? In my BMX days I'd always go for the full chromo frame. MUCH better ride quality than a hi-ten frame lol.

Much different application though, like I said.. for motorsports and stuff it's always seemed to me like as stiff as possible is the way to go.

 

[Roert42]

Is not enough frame flex a thing for off road rigs? I always figured you'd want to be as stiff as possible

Not really sure, but it sounded like from your original post that you were concerned about a fully boxed frame would be too rigid.

 

[Blmpkn]

Not really sure, but it sounded like from your original post that you were concerned about a fully boxed frame would be too rigid.

Aaaah, my comment about articulation? I meant the axles lol

 

[Eddo Rogue]

What do you ride for bikes? In my BMX days I'd always go for the full chromo frame. MUCH better ride quality than a hi-ten frame lol.

Much different application though, like I said.. for motorsports and stuff it's always seemed to me like as stiff as possible is the way to go.

I always liked Chromoly. I tried alum and carbon fiber frames, way to stiff for me, I like flex. Ive had many different bmx bikes, most were pieced together on a good frame. Danscomp was my sears catalog.

For mx bike I ride a yz250 smoker, tried the alum framed hondas, didnt like em. too rigid.

 

[sgtsandman]

Steel is also easier to repair since more people are equipped to work on it. Aluminum is harder to find someone with the needed gear and supplies.

 

[Eddo Rogue]

Yep, good old steel. Cold rolled for the frame, chromoly for the roll cage. Chromoly needs TIG. I would stick weld the frame, or MIG it with thick wire like maybe .045"

 

[Blmpkn]

Yep, good old steel. Cold rolled for the frame, chromoly for the roll cage. Chromoly needs TIG. I would stick weld the frame, or MIG it with thick wire like maybe .045"

What's the deal with chromo needing to be tigged?

The plan would be to mig the frame together since it's what I'm most proficient with. Planning on getting the "horrible farts" 200$ mig after Christmas at some point. I've always used my buddys mig for projects like this but it's time I get my own lol.

 

[Snoranger]

What's the deal with chromo needing to be tigged?

You don’t have to.
Chromoly gets brittle from the heat of welding and should be normalized afterwards (think 1100° oven). The claim is that TIG welding will put less heat into it (or a more focused heat, or something like that) and eliminate the need to normalize it. (I don’t fully agree with this theory, but we don’t have the time or bandwidth for that rant.)
So... you can MIG weld chromoly and bake it in a big oven afterward.