Accepted front-hoop configurations for roll cages (Page 1 of 5)

Thank you, Nick.

thank you. that eases my worries

VoR

Just to add since this is a sticky post and since the question has come up several times already, the Autopower bolt in cage is legal WITH THE ADDITION OF A SECOND DOOR BAR per Nick here:

http://forums.24hoursoflemons.com/viewt … 2338#p2338

Thanks for quickly and accurately replying to all of us and addressing our concerns. You put a lot of worried minds at ease!

The one real difference I know between Lemons and SCCa or NASA cages is the DOM requirement.  Lemons allows ERW but encourages DOM. 

Something to consider is that the standards keep going up so DOM may become required before to long.

The bottom picture looks like our Jegster cage whcih is NHRA approved but uses ERW not DOM.  the middle pic lookslke and Autopower which should use DOM tubing.

It also sounds like the tubes will have to be mandrel bent.  Not for sure though.

True, a good bender will have follower dies and a no-shit main die strong enough to prevent crushing or wrinkling. I have a Pro 105 mandrel bender, it does a real good job. Smooth bends, no wrinkling or crushing. #1 thing to look for: steel dies. Aluminum dies can and will spread, leaving you with an unacceptable bend.

No affiliation other than buying a bender.

http://www.pro-tools.com/105.htm

Okey doke, I screwed up the description: the 105 is actually a 'manual draw bender' and not a 'mandrel bender'. It will still make SCCA etc legal and safe bends and I stand by the 'no aluminum dies' statement.

DOM is not mandatory, it's just "very strongly recommended" under the New and Re-Revised Rules:

3.1.1: Rollbar Tubing and Padding: Minimum tubing size for cars weighing under 3000 pounds as raced is 1.50" x .120" or 1.75" x .095". Cars weighing over 3000 pounds as raced must use a minimum tubing size of 1.75" x .120". Properly-bent, racecar-grade and -quality tubing is mandatory: no stretched or crushed bends allowed. DOM mild steel is very strongly recommended over ERW (seamed) tubing.

Unless you are saying that ERW is not made in 1.5x.120 or 1.75x.095, in which case DOM would be your only choice.

See we have a horizontal bar plus two downward diagonal braces from the ends of the harness bar, as per the 3rd photo in the original post, I am trying to see if we need that continuous diagonal to be added as well.  It wouldnt really add well with the way the cage is set up.

What we have is exactly whats in the "halo Hoop"photo in Nick's post.  The only other thing our cage has is 2 diagonals this is it:

@David: The 'X' is explicitly allowed, not sure about the others.

I agree that this is most likely just a document revision problem, expecting 'real' document control is probably not realistic given the many demands on the organizers' time. I'm sure this'll all be cleared up shortly.

davebs--all three of your proposed door bar designs are acceptable.

X-args--You're absolutely right, the V4 version of the techsheet is the product of a "Document Revision Error" or DRE. Please call tech support in Djibouti.

No, really, we totally screwed the pooch on that one. DOM tubing is NOT mandatory (though recommended). ERW seamed tubing is acceptable. X-args gets bonus points for reading the tech sheet (something we obviously didn't do)--it will be revised shortly.

To avoid confusion for future forum searchers, I'm going to delete the posts that show the DOM requirement (oh, who am I kidding, I'm just covering our tracks so I can lie about it down the road.)