Larger rear subframe mount bolts?

[Mudhen]

Wondering if anyone has ever heard of upgrading the rear subframe mounts to larger bolts?

One of my bolts snapped off when removing the subby...those things look pretty tiny!  I'm going to order some new heelboard repair panels and was thinking about welding larger nuts in there before putting them on.  Wonder if there's enough meat on the trunnion though?

[94touring]

Suppose you could by drilling out the trunnions a size larger or so, but the factory size in grade 8 can hold some serious weight.  Google charts showing tensile and shear strength of them and you might be surprised, then multiple by 8 of them.  The problem with subby bolts breaking on removal is due to them rusting into oblivion.  Lube and grease them up good on installation.

[Mudhen]

The repair panels are backordered at 7...so in my response to them I told them what I'd been thinking.  They said, 'why not tie the rollcage right into the subframe'?

Wow...never thought of that.  I wonder what the implications of it are...seems like it would be pretty awesome, but if it would be, then why wouldn't the Group A cars have done it - they did the more traditional tie in at the top of the shock tower.  I wonder if you can even get there...or would the gas tank be in the way...(since I'm po and won't be doing a fuel cell to start).

I'm really more of a copier, especially when it comes to structural design of a cage.

Actually...maybe it would really be worse?  Better for the strength of the subframe during right-side-up use, but what about in a shiny side down situation?  Now you really are transferring what could be a LOT of load onto those little subframe bolts...

[biketesting]

Roll cage is generally required to be tied into the suspension by SCCA standards.

[Mudhen]

Roll cage is generally required to be tied into the suspension by SCCA standards.

Good point...maybe I should check the regs!   :-[

FIA Appendix J for rallying cages...can't really see anything requiring the rear being tied in with the suspension - front definitely specifies it, though.  Oh...

"8.3.2.5
Additional constraints :
Longitudinally, the safety cage must be entirely contained between the mounting points of the front and rear suspension elements carrying the vertical loads (springs and shock absorbers)."

Guess I could still get to the subframe forward of the shock towers...but I don't think I will...