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914World.com _ 914World Garage _ Rollcage "petty bar"

Posted by: campbellcj Feb 11 2006, 03:17 PM

POC has a rule against passengers (instructors/students) riding in the car if there is a cage tube crossing their 'space'. Apparently there was a fatal crash years ago where contact with this type of bar was deemed to be a factor, so they are not at all flexible on this rule.

Sooo...my choices are to either make it removable, or just ditch it entirely.

Will making it removable negate the extra stiffness added by this bar? If so then I wouldn't bother. In that case, what is the best way to remove a welded bar like this? I sure don't want to have to redo a significant portion of the cage. Is it OK to just cut it out and then grind down the welds?

I am kind of inclined to just ditch this bar and perhaps add some more tubing to the chassis & pickup points to add more stiffness. In the POC points-based classification system this is only 1 pt IIRC and I think I can 'afford' it class-wise.

Any advice appreciated.

Posted by: Dan (Almaden Valley) Feb 11 2006, 03:23 PM

My car has a removable petty bar. I would go with that set up since it does give some front to rear stiffness.
Does you car currently have a full cage. If so I would can the petty bar.

Posted by: campbellcj Feb 11 2006, 03:36 PM

Sorry I forgot to clarify; yes it has a welded 1.5" 8-point cage, built by TonyC about 3 yrs ago. Currently there are no tubes outside of the cockpit.

Dan - what kind of hardware/connectors are used in your removable bar? Is it reasonably easy to remove/reinstall?

Posted by: Dan (Almaden Valley) Feb 11 2006, 03:41 PM

foot plate and backing plate with 2 bolts on floor and one bolt onto middle of hoop with welded tabs to attach to bar.
It is easy in and out...although I never take it out unless the wifey wants to go for a ride in the twisties....that doesn't happen very often since my other car is a Boxster...she likes that a lot more than the 914. Can't blame her for a cruiser.
If you have a TC cage....ditch the petty bar IMHO

Posted by: SirAndy Feb 11 2006, 03:47 PM

if clouded memory serves me, TonyC advised me against a welded in petty bar back when he did my cage.

i opted to not have a petty bar at all, but if i ever decide to get one, it will be removable ...
Andy

Posted by: Racer Chris Feb 12 2006, 07:19 AM

Cut as close to the ends as you can with a sawzall, then grind away the remainder. If you nick (deeply) one of the remaining tubes I would fill that with weld and grind smooth.

Posted by: trekkor Feb 12 2006, 12:09 PM

I would like to ADD a removable petty bar.

Can you leave a couple of inches in the car on each end and weld on thick mounting tabs? Then do the same on the sectioned piece once it's fitted to the tabs.

What tube stock should be used for an add on?

KT

Posted by: campbellcj Feb 12 2006, 01:09 PM

QUOTE (trekkor @ Feb 12 2006, 10:09 AM)
I would like to ADD a removable petty bar.

Can you leave a couple of inches in the car on each end and weld on thick mounting tabs? Then do the same on the sectioned piece once it's fitted to the tabs.

What tube stock should be used for an add on?

KT

TonyC has some "trick" tube connectors that I remember seeing a couple years ago; maybe he or Brad posted a pic here.

I figure the POC tech weenies might not like the protruding stubs when the petty bar is out. I'm just gonna ditch the bar...thanks Chris for confirming it's OK to cut/grind it out as long as I'm careful not to damage the remaining tubes.