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Bracing Framehorns

Smiley - June 19th, 2011 at 06:44 PM

Hi all.

I'm looking to strengthen up the rear end of my car. As some of you will know I had my LHS framehorn crack at the start of the year. I repaired that and now it seems the RHS one is starting to go too.

How have people braced their framehorns? Pictures ideas etc would be great. I know I could buy a K-bar kit but I am exploring all ideas first.
Car is Superbug rear end, currently swingaxle but soon to be IRS.

Smiley :cool:

matberry - June 19th, 2011 at 06:58 PM

Into the internal roll cage is my answer for the best results

If you look closely you'll see the struts that support the frame horns from the firewall attachment points

Like this

Smiley - June 19th, 2011 at 07:01 PM

And if I have no internal cage?

Smiley :cool:

matberry - June 19th, 2011 at 07:04 PM

For the less extreme, you can do a version of a Kafer bar but using your rear cage at the upper bars that go to the shock mounts. You need a tie bar that connects both sides, where they attach is where you want anothe tube fitted that connects to the frame horns. All could be welded if double jointed, open drive shaft commonly refered to as IRS rear end is used, or for your swinger, the drop bar can be removable. The more bolted joints, the less strength.

matberry - June 19th, 2011 at 07:05 PM

Quote:

Originally posted by Smiley
And if I have no internal cage?

Smiley

Yeah, I was getting to that

Smiley - June 19th, 2011 at 07:08 PM

Quote:

Originally posted by matberry
For the less extreme, you can do a version of a Kafer bar but using your rear cage at the upper bars that go to the shock mounts. You need a tie bar that connects both sides, where they attach is where you want anothe tube fitted that connects to the frame horns. All could be welded if double jointed, open drive shaft commonly refered to as IRS rear end is used, or for your swinger, the drop bar can be removable. The more bolted joints, the less strength.

I think I understand what you're saying. I also want to tie the ends of the frame horns into the bottom bars of my rear cage that run forward to the torsion housing.

Smiley :cool:

matberry - June 19th, 2011 at 08:31 PM

Quote:

Originally posted by Smiley
I also want to tie the ends of the frame horns into the bottom bars of my rear cage that run forward to the torsion housing.

Smiley :cool:

The lower bars normally have RHS joining them that ties to the forks near the stock cradle. It's the angled tie rod from there to the top shock mount area that triangulates the bars into a truss.

Joel - June 19th, 2011 at 08:33 PM

My rotary bug was converted back in the 80s before Kafer bars and Berg mid mounts were common on the market here so the the bloke that built it came up with his own versions.

The mid mount is basically exactly the same as Bergs but to beef up the forks he used box section with the top cut out welded the bottom of the forks and did pie cuts at front to follow the contour of the forks at the front.

Sorry these are the best pics I've got of it.

matberry - June 19th, 2011 at 08:39 PM

Yeah Joel, you'd call that a home made Berg style intermediate mount. Definately a recommended addition to anything over stock performance.