Changes in the Door Bar Rules??

I would imagine that the intent of this rule is to get rid of the single bar side protection stuff. Like the old welded-in former autopower bolt-in cages.

Mine has a bar that runs along the rockers on both sides, and Xs on both sides (driver side protrudes into door, passenger side does not).
I would think this qualifies as 3 connections from the main hoop to the front.

Note the "I would think."

Scott, who has always, and still feels, that if I hit anything hard enough to seriously compromise the cage in my car I'm probably already screwed anyway.
 
Originally posted by Tyson@Sep 26 2005, 08:43 PM
yeah, im not talking the weight benefit.  just why would the CRB allow this change since they have a history of only changing things on the basis of safety or factual error.
i suppose the only difference is that it changes the load path on a straight T bone more directly to the vertical bars (pushing instead of pulling the welds)  but that doesnt mean anything to make a safer cage for the driver on the other side of the car.  thats why im asking...
[snapback]61248[/snapback]​
Click to expand...

Well a lot of cars have nothing on the pass side. Perhaps the CRb did it witha big picture in mind...it allows touring cars that have the door bars as required to migrate into IT, (if there is such a migration possible, perhaps it's paving the way for future moves),

and the weight break was seen as a "carrot" to get guys to put something...anything(?) in.

As it is, it is so open as to be very effective, IMHO.
 
I would disagree that anything can be put in NASCAR style is defined and must intrude into the door cavity, not just any ole door bar is going to permit gutting.
 
Yeah Ed, but there's no requirement on just how far or how much it must 'intrude'. So, if it intrudes by 0.1", you're allowed to gut the door.
 
Originally posted by Bill Miller@Sep 27 2005, 02:20 AM
Kirk,

I think I just came up w/ a name for the new car.  Ugly Duckling!!!
[snapback]61263[/snapback]​
Click to expand...

That's your door, by the way, Bill. :D
 
Check out this shizznit, boyz...

DSC01922.jpg


From Robbie Gordon's trophy truck. More at...

http://www.desertrides.com/features/vehicles/gordonTT/

K
 
That is some of the most retarded fabrication I have ever seen. What robot did the welds? That is just rediculous.
 
Spectacular...TIG, right?

Ever check out the welds on road and mountain bikes? Or even a Trac Rac? (the aluminum racks you mount on your pick up to carry lumber and ladders and such)
 
Yeah Jake, that's TIG work. I actually have a friend that does work like that, the guy is just insane. I can't even imagine how many hours went into the fabrication of that car, it's mind boggling. Some very nice work, that's for sure!
 
I'm a little late to the party here, but I think Kirk needs to turn in his rules nerd badge. An "X" is comprised of two bars.
 
Originally posted by Geo@Oct 5 2005, 10:08 PM
I'm a little late to the party here, but I think Kirk needs to turn in his rules nerd badge.  An "X" is comprised of two bars.
[snapback]61891[/snapback]​
Click to expand...

Actually George, it's comprised of 3 bars, 1 continuous one that runs from the main hoop to the front down tube, one that runs from the main hoop to the continuous bar, and one that runs from the front down tube to the continuous bar.

I personally think an X meets the spirit of the rules, but I can see where it could be argued that it does not meet the letter of the rules.
 
I'm forced to try to be consistent, having argued for years that a car that has ONLY an X back from the main hoop to the strut tops (or wherever) doesn't have "2 bars" holding that hoop up. At one point in the structure, there is in fact only one tube of x-sectional area between the middle and the back end of the structure.

The same applies for door bars, to my thinking but we're dealing with that in the new design.

K
 
An 'X' in side view can be done with two bars - if the front and rear hoop are not in the same vertical plane - I've seen it done, where the two tubes are straight and crisscross without cutting; really depends on the shape of the roll hoops. It just needs one of the tubes to kick in at top or bottom (most likely bottom)

Question, though - are they still two tubes if the tubes are notched and welded, but not completely cut in two? Would such a design be inherently 'safer' than the 3 tubes Kurt described?
 
Sorry, late to the thread.....

Originally posted by Knestis@Sep 22 2005, 11:13 AM
A cage builder on the East coast has made it common practice to leave the traditional parallel rear supports (from the main hoop) out of his designs, instead using ONLY an X. I've long argued that this approach does NOT meet either the letter or engineering aguments behind the requirement. Over some portion of that span downward to the rear end of the car, there is functionally only one tube there. The minimum cross-sectional area of the rear portion of the cage structure is just slightly over pi times one-half of the tubing diameter squared - or approximately "not very damned much."

To my mind, the same applies here.
Click to expand...

I've wondered about this for a while too. I'm interested in thoughts about the rear X....

But I feel it's a bit different for the rearward X's vs the door X's. Why? Because the door X's possibly take a direct impact. Having only one door bar (or the equivalent cross section area) means that one bar of strength is taking the force of the impact.

For the rearward X, it keeps the main hoop standing and keeps the rear of the car mostly behind you in an impact.

In the case of the main hoop, any attempt for the main hoop to topple backwards puts compression loads through the bars of the X. Assumine the force is parallel to the bars, they should be plenty strong (and the triangles should be strong if the hoop trys to topple backward AND right/left).

In the case of rear impact, the forces are also compression loads through the X brace, just compressing towards the main hoop instead of away from it. Again, the rear X seems like it would be plenty strong in this sense too.

About the only issue I can see with the rear X is if a car jumps over your bumper and runs smack into the center of the X. It hits a weak point, and I'd guess that the thing is not very strong perpendicular to the X. I think it would buckle there. Especially considering how long those X's are for the rear (I have a cage built by the particular builder you speak of.)

And that impact seems like exactly what would happen in a side impact to the door X. The only thing keeping the X from collapsing with a perpendicular impact is the tension of the bars pulling at the main and front hoops. The weakest point in tension is the center of the X, which could pull apart from X to > < if the center shears. (I think true in a X-brace case too, including Pablo's one with the gussets - unless the top and bottom of the center X were also gusseted.) I think 2 complete side bars would double the amount of force required to shear, as well as spread the force over a larger area.

I guess this is off the topic of whether an X fits the rules or not, and more asking the question of what really is a good idea for side impact?

joe
 
Two cents. I'm not a welder, nor do I play one on TV, but I've seen the need to use one in the past.

My guy tells me that it's much harder to make an "X" and gusset it properly than to weld two bars parallel to the front and main hoops. Plus, the bars are continuous, not cut and rewelded. As an aside, he offered to modify my cage in such a manor and add small bars between the main door bars to add support. His and my theory is that in a side impact event, with the "X" bar configuration, it would be a lot easier for the intrusion of cars and car parts into the cockpit than with the parallel bars.

I guess you could look at shark cages as an example. They put parallel bars in those to keep the bad things out.
 
***An "X" is comprised of two bars.***

George, from my point of understanding the word TWO (& the rules) Kirk may keep his card.

Forgetting about the cute bend around/half cut bars that have been exposed within this thread to form the "X" side protection & "X" main hoop braces I understand the rules for both the side protection & the main hoop rear braces to say TWO tubes or two braces. Anyone who uses THREE seperate tubes/braces to fab the side protection or main hoop braces "X" is NOT legal to the written rule.

The next thing we'll have people fabing their main hoop out of several pieces of tube when the rule says one (1) continious length of tubing shall be used.

Opp's, how can I be so dumb. You folks are using new math & when the rule says TWO, the rule via new math really means THREE. :blink:
 
Originally posted by charrbq@Oct 6 2005, 11:43 AM
I guess you could look at shark cages as an example.  They put parallel bars in those to keep the bad things out.
[snapback]61944[/snapback]​
Click to expand...

I went into one of those shark cages this summer about 3 1/2 miles off the shores of Hawaii... Suprisingly I felt rather safe!!!

Ok so that has nothing to do with this, but whatever, it reminded me of our adventure...

Raymond "shark bite" Blethen
 
Originally posted by ddewhurst@Oct 6 2005, 05:15 PM
***An "X" is comprised of two bars.***

George, from my point of understanding the word TWO (& the rules) Kirk may keep his card.

Forgetting about the cute bend around/half cut bars that have been exposed within this thread to form the "X" side protection & "X" main hoop braces I understand the rules for both the side protection & the main hoop rear braces to say TWO tubes or two braces. Anyone who uses THREE seperate tubes/braces to fab the  side protection or main hoop braces "X" is NOT legal to the written rule.

The next thing we'll have people fabing their main hoop out of several pieces of tube when the rule says one (1) continious length of tubing shall be used.

Opp's, how can I be so dumb. You folks are using new math & when the rule says TWO, the rule via new math really means THREE. :blink:
[snapback]61957[/snapback]​
Click to expand...

God, this sort of stupid stuff is the resaon I've not been around for a while. While I am not a tech inspector, I'm confident they won't be so goofy about this. An X is two tubes.

There are many times I think this site does more harm than good.
 
You must log in or register to reply here.
Back
Top