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Triumph TR6 - lower cruciform

Hi all

Man, there is so much information on frame repairs on the internet, and of course there are companies that are manufacturing new one. RATCO at has good information.

My question is; is it a good idea to bolt the lower cruciform on, this allows easier fitting of exhaust systems?

lw gilholme

Les, this is just my opinion. Our frames aren't very stiff to begin with and then bolting the cruiform,
(which by its very nature has to be the stiffest part of the frame), would be like spot welding it. True
the bolts will not pop open the way a spot weld will,
But the only advantage is ease of installation for the muffler man who has probably delt with a lot worse.
When I removed the original rusted cruiform I replaced it with 1/8th in. plate and larger in area. Much stiffer, you really notice it in the corners.
Christopher Trace

That's a good idea but probably would compromise the frame rigidity. When the frame twists the bolts may not hold it from shifting like a good weld would.
I say its a good idea because I remember replacing my exhaust system and it was a big PIA!!! My pipes are still jambed against the cruciform.. I'm suprized it doesn't rattle or buzz.

HP Henry Patterson

Hello Les,

I think Chris and Henry nailed it right.... no bolts or no rigidity. Use a 10g plate cut to size and shape with perhaps longer "sleaves" on the T-shirt, drill/ punch 3/8" holes for plug welding, cross band the bottom of the plate with 1/4" x 1" strips of band iron to simulate the embossings and to futher strengthen the plate.... a chassis can't ever be too ridgid. Let the suspension flex as that is what it is designed to do. I can send a few photos of the fix i did on my chassis... looks stock but will preform at a much better level. I even put small half moon gussets inside the crusiform area to further reduce movement.
One other improvement is to internally reinforce the lower front cross member... 2x2 box tube plug welded to a 10g plate laid flush and inside the cross member... again a completely stock appearance but with greatly improved torsional rigidity.

Cheers, Rob
Rob Gibbs

To all

Thanks for the advice, I guess I will put up with the PIA and weld the plate.

I would appreciate any photos, drawings etc, I intend to pull the engine, gear box, and everything else on the front end this weekend (weather permitting).


lw gilholme

Les if I can offer my 2 cents.

As per eberyone, I agree with welding it.

Then if you wish, install a stainless steel exhaust system. Should give you years of service and not have to worry about exhaust service later.

Michael S. Petryschuk

Les... you've got mail. Sounds like you're in for a busy weekend
Rob Gibbs

This thread was discussed between 17/05/2006 and 20/05/2006

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