SFBD question

is there a serious issue with laying the tubing on the side under the cab when doing a sfbd? i am planning on using 2x3 with 1/4" wall. ill also be using 2x2 with 1/4" wall for under cab crossmembers.

id figure with decent gusseting where the new tube meets the orignal frame and beefy crossmembers it should be plenty stong enough. am i correct in thinking this or am i way off?

also, i am planning on doing roughly a 4.5" body drop on the isuzu, and possibly a 3" chop. id like to keep as much head room as possible so i can fit in it. (im 6'2) as it stands, if i lay the tube on the side, ill need about an 1" trad to get it to lay where i want it to. (3/4" from the doors)

well you might as well use 2x2 if you are layin 2x3 on its side, theres a big difference in strength, besides torsional stiffness (how much the frame will twist), the problem areas are gonna be before and after the cab mounts, 2" tall tubing is going to flex at those points, its alot safer to channel the cab alittle than to use 2" tall tubing.

i definately agree that 3" tall is way stronger than 2" tall.by no means am i just gonna cut out a section and just weld in tubing and move the body mounts. for instance, ive been lookin at hopntoy's toyota.

im not looking into that radical either, but what i was lookin at where the frame ties together and whatnot. like this. and something similar in the front in the form of a mini cage

NO THE 2X3 WONT BE AS STRONG ON ITS SIDE,BUT I DONT THINK A MINI IS EVER GONNA HURT 2X3 X.25 STEEL.MAYBE IF IT WAS A V8 FULLSIZE IT MIGHT TWIST IT OR BEND IT BUT U WONT HAVE A PROBLEM

what about welding two pieces of 2X2X1/4 together then layin it on its side thats gotta be strong enough

hm.. take a 2x4 and put it on its side and stand on it, notice how it bows? stand it up (4x part up) and stand on it, kinda the same with the weight of all the parts on your truck to a piece of metal. you can get by with using a lighter 2x3 3/16" wall tubing, save some weight and add strength by standing it up, ive actually used 2 1/2" squared with a 1/4" wall before, and worked pretty good, but i plated the areas going to the front clip and after the rear cab mounts nicely because there was flexing in those areas. my dodge was subframed under the cab with 2 1/2" squared also, but it equaled to 3" when i set it inside the stock frame because of the lip on the lower part of the c channel.

Originally posted by bgp1mpin



what about welding two pieces of 2X2X1/4 together then layin it on its side thats gotta be strong enough

than you might as well use 2x6 and like chris said it's the torsional weight that might be the problem...

id recomended channeling the cab a little bit and using 2x3 stood up......you would still need to brace your joints but you wouldnt have to worry about flexing and bending a frame rail.....do it right the first time and save time and money in the long run....

hey mike i gotta question about submitting tech articles to the mag who do i talk to?