I am planning on building a custom frame for my next jeep. I am going to use 2x4 box, but what wall should I use?

Craig

1/8" should be enough, especially if the cage will tie in and truss it. Anything more would be way heavy.
I'd go smaller, 2x3 or 2x2 if the cage is helping, every inch closer to the ground helps.

Have you looked at wall thickness of a stock jeep frame...they are only like an 1/8"...very thin I was surprised:eek:

Hey, how have you been!
1/8 or 3/16 would kind of depend on the overall weight of your design. Are you talking about going high-horse V-8 with a lead foot or something small?
Doc.

1/8" will work, I used 3/16" to error on the safe side with the weight of the drivetrain I'm using.

CJ

i'd use 1/8" 2x3 tube ...

- jack

I'll be running my 5.0, nv4500, atlas II, HP60's, and 42.5's. The axles and wheels are heavy (hummer rims), but not as heavy as CJ Lagos's rockwells. I don't want to have any problems with strength, but I don't want it to be too heavy. I still plan on using a "modified jeep tub". I'm pulling the jeep apart right now, so I can design the frame.

Craig

wow.....2",3",4":eek: ....I used 5" x 2" x 3/16" tube....

5" because wider is better....
3/16" because I am but welding the angles and thicker is better .....(I may one day use the frame as an air tank).
I used 4" on the cross members.
I also built the frame wider for stabillity and other concerns like ....Inside the rail exaust,power steering,huge Atlas,sb350 all in a tiny 71 cj5 renegade so it's not a big rig.

round dom tube :D


seriously.......... look at essigs frame, very nice.!

Originally posted by BossGrip
wow.....2",3",4":eek: ....I used 5" x 2" x 3/16" tube....

5" because wider is better....
3/16" because I am but welding the angles and thicker is better .....(I may one day use the frame as an air tank).
I used 4" on the cross members.
I also built the frame wider for stabillity and other concerns like ....Inside the rail exaust,power steering,huge Atlas and so on...
Mind you I have a little 71 cj5 with a 350sb sm420 and an atlas ll
-Kerry

DAMN that thing must be heavy!!! I built my front crossmember out of 2x5x3/16 and it is HEAVY

I would go 2x4x.125

mine is 2 x 4 x .188
if I were to do it again I would build a lighter frame
I don't think I would even use 2 x 4, but rather two rows of 2" square .120 or thinner. Mine should be plenty beefy, but my next project will be heading towards the lightweight side, and I'm not even done with this one yet!!!!

there's pictures of my frame in some other thread

http://www.pirate4x4.com/forum/showthread.php?s=&threadid=39235

Originally posted by NE-RokToy


DAMN that thing must be heavy!!! I built my front crossmember out of 2x5x3/16 and it is HEAVY

I would go 2x4x.125
Well it's a give and take I guess it depends on what your design is.
If I went the 2x4 route it would have only saved me 40 lbs

My Frame
22' of 2x5x3/16=179.3
10' of 2x4x3/16= 68.7
Total Weight 248.0 lbs

Size reduction
22' of 4x4x3/16=151.14
10' of 4x3x3/16= 55.9
total weight 207.04 lbs

I like the thicker option for hiding all my running gear and mufflers plus it gives me more surface area to run cables brake lines body mounts hangers and so on.
If everything works out just right I'll have a rather smooth bottom and about 9 gal of air storage.
I realize that weight can be an issue with gas mileage but for what I do I need strength and a flat bottom.

It's more than gas mileage. Xtra weight takes more traction to get up the same object, more power to get moving, more springs to hold the thing up, bigger brakes, axles, shocks...
The only time more weight is good is when towing or snatching.

Originally posted by dirtrod
It's more than gas mileage. Xtra weight takes more traction to get up the same object, more power to get moving, more springs to hold the thing up, bigger brakes, axles, shocks...
The only time more weight is good is when towing or snatching.
Yes I get your point....
I was thinking more along the lines of the 40lbs differential of the two options I listed.
I realize the chain reaction but I didn't start at the frame when engineering my rig. I started with the componants and an overall goal.
If I was going to stay light I would have stuck with the old wimpy frame I started out with.:)
The weight I added to my frame will hopefully be subtracted +/- from the reinforcing I would have to do if I downsized.
-Kerry Boss

It's better to have the weight in beef, rather than pork. ;)
I have a big block which is probably 100lbs. more than I need, but I like the motor, so I put up it, and try to keep an eye on the other things I put on.