Rear shock mount

What size tubing is typically used for a rear shock mount? Looking to make a tube to go between the rear frame rails then have some tabs off of it.

.083 1 5/8 tied into the cage with 1 1/4

Or you could mount your tabs sideways on the frame rails.

1 5/8 like ^^he said.

I think the "best" tubing OD & wall thickness for a rear shock crossmember/mount really depends on what material you're going to use, if the rear main cage support bars attach to it, if the tube will have additional supports, what the width of the bar is going to be, and how close/apart the shocks will be on the tube.

As the needed/required width of an "unsupported" (no added diagonal braces) tubing shock crossmember increases more & more, the OD & wall thickness should also be increased a little. Adding some diagonal braces to a wide shock mount tube makes it more rigid & lets you use a thinner wall if you want to.

I guess some basic suggestions for a "wide" stock suspension/mini tub/backhalf non "SFI" car would be......

(A) A really wide unsupported shock crossmember tube (for a "stock" rear frame width) with the shocks mounted as close to the main frame rails as possible = 1- 5/8 x .083 (cm) or .120 or .134 (ms).

(B) Same as above but with added diagonal braces running from the rear cage bars down to the shock crossmember tube = 1-1/2 or 1-5/8 x .083 or .065 (cm) or .108 or .120 (ms).

(C) If the rear main cage support bars actually attach to the shock crossmember it's self (instead of to the main frame rails) then the shock crossmember should be made of at least as big material as the cage bars attaching to it to keep the tech inspectors happy.

Thanks for the replies. This my street car I am building to do some autocross racing with. There will be no cage just a back half tied into the factory body with a 3 link (torque arm), watts link and coil overs. This all ties into the subframe connectors that are tied into the rocker panels.

Tubing is impossible to find where I live so I will have to buy it online. I was thinking of getting some Allstar tubing from Summit but they have both DOM and regular tubing with a seam. For a shock mount I really didn't see if it would matter about the seam or not.

Summit tubing.

The front end is a little lower now.

wolfe racecraft and mia motorsports are both ready to drop ship tubing. deal with both all the time.

jasonf wrote:.....This my street car I am building to do some autocross racing with. There will be no cage just a back half tied into the factory body with a 3 link (torque arm), watts link and coil overs. This all ties into the subframe connectors that are tied into the rocker panels.

Well since we are really talking more "street rod" and less "drag car" (no roll cage support) it might be an idea to think about increasing the tubing size for the coil over shock crossmember a little more than the above suggestions. How much bigger really depends on how far inboard both shocks will sit on the crossmember & the total width of said crossmember.

The minimum now for an un-supported crossmember would probably start at 1-3/4" OD x .120 or .134 wall ms just to be safe. And since it's probably going to see more assorted "street/highway use" dangers (pot holes, etc) the more ductile mild steel tubing is probably a better choice than 'moly tubing.

I would mount the shocks to the frame rails in that application and then just put some bracing between the frame rails.

This setup would be pretty tough for that app.

This is a picture I borrowed from the Griggs site. It's been a bit since I mocked it up but IIRC the top of the shock will be about 6" in from the frame rail. I have the griggs x member but it was made for a Mustang and I moved the rails anyways so I was just going to do things a little different.



I was going to make a stronger x member and mount the watts link to the member like the Fays unit.

when i boxed the frame on my 40 pickup i used a sn95 mustang rearend and layed the shocks in like that.it works ok and rides real good but it lets the body roll a lot.i do have a swaybar on the rear but not on the front,yet.just something to think about and the falcon is TUFF! i like it.

i used a peace of 2x3 tubing for my upper shock support