Rule book discrepancy: ROLL BAR

Bobby Zlatkin · 09-10-2008, 04:25 AM

If I'm reading the NHRA rule book correctly, there is a discrepancy on pg. #76, 4:10 Roll Bar.

In diagram, 4:10, it states, "All materials must be 1 3/4" O .D. mild steel ................except A, (rear braces that go into the trunk) which is 1 1/4" O.D.

In the paragraph just above the diagram, it states: "Rear braces must be of the same diameter ,,,,,,,,,
as the roll bar.

Which is it? Can I use 1 1/4" for the rear braces or do I have to use 1 3/4"?

Dave Goob Cook · 09-10-2008, 09:10 AM

Wow, I never noticed that, and it does need clarified.
Kits all come with 1 3/4" for all tubes.

Better check with your Division Tech director for a clarification....I'm going to do the same this weekend.

55 Chevy · 09-10-2008, 11:24 AM

That discrepancy has been in the rule book for a long time. I remember noticing that sort of thing and asking about it 15 years ago as it effected me at the time. I think it was all 1 3/4" if I remember right, but not positive.

RPinoski1 · 09-10-2008, 03:22 PM

The cross bar that the seat bolts to is the "A" bar. Not the rear bars. Hope this helps.
Rich

John Mason · 09-10-2008, 05:47 PM

Rich is correct. In older rule books using this picture there was an arrow from the "A" to the cross bar that has been deleted somewhere but the intent remains the same - all parts of the roll bar must be the same size EXCEPT the cross bar.

goinbroke2 · 09-18-2008, 06:02 PM

Here's a question, does the hoop have to be a single piece? What I mean is, I have a bunch of 8ft pieces of 1.75 tube. I am building the roll bar and 8ft is not long enough to go from floor up over and back down to floor. Can I use two pieces of tube and run a joint or splice tube inside? (not a class car but could relate)
I need a piece approx 10 1/2ft long to do it in one piece.

Run to Rund · 09-18-2008, 11:36 PM

The hoop has to be one piece. That is why a 50 pound chrome moly kit has to be shipped truck freight for $200, grrrr.

Tom P · 09-21-2008, 10:33 PM

The 8 feet might get you a J shaped main hoop like i run. The lightest legal roll bar. The main hoop comes up from the left rocker over my head and then drops to the passenger side rocker. There is one side bar and one back brace. The crossbar is about 3 feet long and i can still access the rear seat area.
It doesn't help chassis strength but weight is about 40 lbs less than a normal 6 point.

goinbroke2 · 09-24-2008, 09:19 PM

That's a good idea I never thought of! I might of found some cheap heavy wall 1.75 tube that looks to be 10ft or so. If it doesn't pan out I might go with the J bar.

09-10-2008, 04:25 AM	#1
Bobby Zlatkin Member Join Date: Mar 2003 Location: Mills River, NC Posts: 417 Likes: 0 Liked 0 Times in 0 Posts	Rule book discrepancy: ROLL BAR If I'm reading the NHRA rule book correctly, there is a discrepancy on pg. #76, 4:10 Roll Bar. In diagram, 4:10, it states, "All materials must be 1 3/4" O .D. mild steel ................except A, (rear braces that go into the trunk) which is 1 1/4" O.D. In the paragraph just above the diagram, it states: "Rear braces must be of the same diameter ,,,,,,,,, as the roll bar. Which is it? Can I use 1 1/4" for the rear braces or do I have to use 1 3/4"? __________________ Bobby & Norene Zlatkin L/SA

09-10-2008, 09:10 AM	#2
Dave Goob Cook Member Join Date: Dec 2006 Location: Indy Posts: 422 Likes: 0 Liked 0 Times in 0 Posts	Re: Rule book discrepancy: ROLL BAR Wow, I never noticed that, and it does need clarified. Kits all come with 1 3/4" for all tubes. Better check with your Division Tech director for a clarification....I'm going to do the same this weekend.

09-10-2008, 11:24 AM	#3
55 Chevy Member Join Date: Feb 2008 Location: Calgary,Alberta area Posts: 221 Likes: 15 Liked 12 Times in 11 Posts	Re: Rule book discrepancy: ROLL BAR That discrepancy has been in the rule book for a long time. I remember noticing that sort of thing and asking about it 15 years ago as it effected me at the time. I think it was all 1 3/4" if I remember right, but not positive.

09-10-2008, 03:22 PM	#4
RPinoski1 Member Join Date: Jan 2002 Location: PLACERVILLE, CA Posts: 182 Likes: 0 Liked 0 Times in 0 Posts	Re: Rule book discrepancy: ROLL BAR The cross bar that the seat bolts to is the "A" bar. Not the rear bars. Hope this helps. Rich

09-10-2008, 05:47 PM	#5
John Mason Member Join Date: Apr 2002 Posts: 147 Likes: 0 Liked 0 Times in 0 Posts	Re: Rule book discrepancy: ROLL BAR Rich is correct. In older rule books using this picture there was an arrow from the "A" to the cross bar that has been deleted somewhere but the intent remains the same - all parts of the roll bar must be the same size EXCEPT the cross bar. __________________ John Mason 7743 SS

09-18-2008, 06:02 PM	#6
goinbroke2 Senior Member Join Date: Mar 2002 Location: NS CANADA Posts: 714 Likes: 641 Liked 178 Times in 63 Posts	Re: Rule book discrepancy: ROLL BAR Here's a question, does the hoop have to be a single piece? What I mean is, I have a bunch of 8ft pieces of 1.75 tube. I am building the roll bar and 8ft is not long enough to go from floor up over and back down to floor. Can I use two pieces of tube and run a joint or splice tube inside? (not a class car but could relate) I need a piece approx 10 1/2ft long to do it in one piece.

09-18-2008, 11:36 PM	#7
Run to Rund Senior Member Join Date: Sep 2007 Posts: 574 Likes: 6 Liked 44 Times in 22 Posts	Re: Rule book discrepancy: ROLL BAR The hoop has to be one piece. That is why a 50 pound chrome moly kit has to be shipped truck freight for $200, grrrr.

09-21-2008, 10:33 PM	#8
Tom P Senior Member Join Date: Mar 2002 Posts: 699 Likes: 29 Liked 224 Times in 90 Posts	Re: Rule book discrepancy: ROLL BAR The 8 feet might get you a J shaped main hoop like i run. The lightest legal roll bar. The main hoop comes up from the left rocker over my head and then drops to the passenger side rocker. There is one side bar and one back brace. The crossbar is about 3 feet long and i can still access the rear seat area. It doesn't help chassis strength but weight is about 40 lbs less than a normal 6 point.

09-24-2008, 09:19 PM	#9
goinbroke2 Senior Member Join Date: Mar 2002 Location: NS CANADA Posts: 714 Likes: 641 Liked 178 Times in 63 Posts	Re: Rule book discrepancy: ROLL BAR That's a good idea I never thought of! I might of found some cheap heavy wall 1.75 tube that looks to be 10ft or so. If it doesn't pan out I might go with the J bar.