ok now that i built the stb now i was thinking i need sfc's. i built the stb for next to nothing why caint i build the sfc also. i just got a couple questions. i really like the idea if the round tube for ground clearence {my car sits real low}. i used 1.25" od x 1" id pipe for the stb will this be good enough for the sfc or would i need to go bigger?

 

What about using rectangle tubing? That might be able to tuck up under the car even better.

Post pics&dimensions of ur build. Im planning on making my own in a couple months too

 

I am personally wanting something like the BMR SFC008 design that will work with my LTs and true dual setup im wanting to run. If anyone has dimesnions can you PM me with them or post em up? (sorry dont mean to hijack your thread)

 

square or round will still have the same ground clearance, it all depends on where you route them. I would say at least 1.5 tubing, if not 1.625 or 1.75. Dont use pipe, use steel tubing. Pipe is rather "soft".

.120 -.134 wall tubing is more than enough

 

I'd say concentrate more on wall thickness than tubing size. Wouldn't a thicker wall basically allow a thinner tube, to a limit, of course. I'm not suggesting 1/2" thick, solid wall tubing or anything like that.

 

Actually its the opposite, for the element itself. Either in bending or in torsion, having the material further away from the center will make it stronger leaving out issues from having walls too thin that can buckle under load or similar problems. However I was thinking about it after your post and if you view the entire car as a structure, the lowest areas furthest away from the vehicle's center (where the rockers are) are going to be in tension almost all the time, if not all the time. That makes the location of the metal in the element itself (the sfc in this case) kind of irrelevant. I wouldnt wash it away completely mind you, but its not going to end the world to use something a little smaller.

 

Look at the size and thickness of the Spohn and UMI sfc's to use as a reference.

The stb tubing is too small.

 

I don't know if you want to cut up your floorboards or not, but I just finished sfc's in my car. They're made of 1 5/8" 4130 chromoly .083 wall. This is how they look, and also no ground clearance issues.


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in this picture its only tacked up but you can get the idea.

 

does anyone that have the spohn tube sfc know what size they used? i am thinking 1 1/2" or 1 3/4" but not sure . i like the look of the spohn where its almost like you cant see them.

 

The Spohn website says.....
"Our "truss-style" framing system is constructed of 1.75" x .120" wall DOM (round) tubing for serious, uncompromised rigidity."

For comparison, UMI says.....
"- Built using 2.000” x 1.250” x 0.120” Mild Steel Rectangular Tubing"