Anyone installed a "kit" rollbar?
- Thread starter mad999
- Start date
turbodave231
Moderator
- Joined
- May 24, 2001
Mad999,
Where is Ravenna, MI? I installed a Comp Engineering roll bar in my car only to pull it out in favor of a full chromoly cage. Save your money and don't buy a mild steel bar or cage kit.
I can recommend an outstanding chassis guy (Total Fabrication) near Grand Rapids who will custom bend an awesome bar or cage, and this guy does some of the nicest work I've ever seen. He won't break the bank either.
Take a look at the pictures of the cage in my car in the photo album link below.
PM me if you are interested in talking to this guy.
Dave
Where is Ravenna, MI? I installed a Comp Engineering roll bar in my car only to pull it out in favor of a full chromoly cage. Save your money and don't buy a mild steel bar or cage kit.
I can recommend an outstanding chassis guy (Total Fabrication) near Grand Rapids who will custom bend an awesome bar or cage, and this guy does some of the nicest work I've ever seen. He won't break the bank either.
Take a look at the pictures of the cage in my car in the photo album link below.
PM me if you are interested in talking to this guy.
Dave
Sam Colalillo
low 9's w/ a 109
- Joined
- Jan 12, 2005
turbodave231 said:
Dave,
Did this guy do your cage?
I saw Daves car at the M10 event in stanton and I have to say it was very meticulously done.
I used an S&W kit in my car. Kinda pricey after shipping but the the fit was perfect. I also ordered the swing out doors and pro-street runners that go through the rear speaker holes so I had quite a bit of extra tubing that I used to add to the kit. All in all worth the money though.
- Joined
- May 27, 2001
Dave,
That cate looks nice what is it certified to?
I thought the 25.5 needed a funny car halo?
That cate looks nice what is it certified to?
I thought the 25.5 needed a funny car halo?
turbodave231
Moderator
- Joined
- May 24, 2001
John,
My cage is NHRA certified to 8.50. That is plenty good for me unless I hit the lotto.
Sam, Tim Clow at Total Fabrication did my cage. All custom bent Chromoly. The car is actually LIGHTER with a full 12 point cage, chute mount and rear antisway bar versus just the 6 point mild steel bar I had previously.
Mild Steel is easy for most guys because you can MIG weld it. Chromoly must be TIG welded and as such, you are better off letting someone custom bend it for you because they will do the TIG welding. I wouldn't buy anybody's chromoly kit unless you can TIG weld.
The new cage fits very close to all interior trim. The dash bar is not visible unless you stand on your head to see it, the new cage has the door bars X'ed and it is easier to get in and out that my old roll bar. Best money I ever spent.
Tim installed a custom rear anti-sway bar that I haven't even tuned on yet. The car is pulling low 1.4's for the 60'. I need to get the car on the scales to get the bar adjusted.
My cage is NHRA certified to 8.50. That is plenty good for me unless I hit the lotto.
Sam, Tim Clow at Total Fabrication did my cage. All custom bent Chromoly. The car is actually LIGHTER with a full 12 point cage, chute mount and rear antisway bar versus just the 6 point mild steel bar I had previously.
Mild Steel is easy for most guys because you can MIG weld it. Chromoly must be TIG welded and as such, you are better off letting someone custom bend it for you because they will do the TIG welding. I wouldn't buy anybody's chromoly kit unless you can TIG weld.
The new cage fits very close to all interior trim. The dash bar is not visible unless you stand on your head to see it, the new cage has the door bars X'ed and it is easier to get in and out that my old roll bar. Best money I ever spent.
Tim installed a custom rear anti-sway bar that I haven't even tuned on yet. The car is pulling low 1.4's for the 60'. I need to get the car on the scales to get the bar adjusted.
Ravenna is between Grand Rapids and Muskegon. Don't think I will go any lower than 10.99 so the 6 point should be ok. I also read the larger tube was mandatory for the 6 point, so I thought it wouldn't pass tech using an 8 point and just making it a 6. I just hate the thought of not being able to get people in the back seat, it is just a street car. Also if I read it right I only have to use the side bar going forward on the drivers side correct? I know my wife will not be happy with getting in with the side bars.
The side bars can swing with a pin on one end could you use pins on both ends to remove it completely? What about the bar going behind the seats, could that be removable, probably defeats the purpose of the bar but it would be nice.
thanks for the input so far.
The side bars can swing with a pin on one end could you use pins on both ends to remove it completely? What about the bar going behind the seats, could that be removable, probably defeats the purpose of the bar but it would be nice.
thanks for the input so far.
Sam Colalillo
low 9's w/ a 109
- Joined
- Jan 12, 2005
Some one is currently borrowing my NHRA rulebook so I am going off of memory here.
) 11.49 to 11.00 non-convertible must have a roll bar installed.
) Roll bar must be welded to the frame of a full frame non-unibodied car.
) Roll bar must be 1.75 dia. Tube (.118” wall thickness if using mild steel and .083” wall thickness if using chrome moly tube.
) The brace that is mounted horizontally behind the drivers seat attaches to both side of the main hoop can be 1.25” dia tube, and must be welded to the main hoop.
) Swing outs are allowed
) Forward support of the main hoop is only necessary on the driver’s side.
And you are correct the tubing sizes for a roll cage are smaller. Most of the tubes must be 1.625, and the bars that kick back toward the rear of the car 1.50, and the behind drivers seat bar is 1.25.
I bought a chassis engineering mild steel 6 point roll bar kit from Lane automotive in Watervilet Michigan. Did not have to pay the high freight price because they keep it in stock and I picked it up right at their store for under 200 dollars. I even upgraded to the bars that allow a person to use the back sat by routing the tubing through the speaker holes. At the time it seemed like the right thing to do because of the price, but now I am wondering how much weight I could have saved by using chrome moly.
I am going to go figure that out, I’ll post my research on this thread when I am done.
) 11.49 to 11.00 non-convertible must have a roll bar installed.
) Roll bar must be welded to the frame of a full frame non-unibodied car.
) Roll bar must be 1.75 dia. Tube (.118” wall thickness if using mild steel and .083” wall thickness if using chrome moly tube.
) The brace that is mounted horizontally behind the drivers seat attaches to both side of the main hoop can be 1.25” dia tube, and must be welded to the main hoop.
) Swing outs are allowed
) Forward support of the main hoop is only necessary on the driver’s side.
And you are correct the tubing sizes for a roll cage are smaller. Most of the tubes must be 1.625, and the bars that kick back toward the rear of the car 1.50, and the behind drivers seat bar is 1.25.
I bought a chassis engineering mild steel 6 point roll bar kit from Lane automotive in Watervilet Michigan. Did not have to pay the high freight price because they keep it in stock and I picked it up right at their store for under 200 dollars. I even upgraded to the bars that allow a person to use the back sat by routing the tubing through the speaker holes. At the time it seemed like the right thing to do because of the price, but now I am wondering how much weight I could have saved by using chrome moly.
I am going to go figure that out, I’ll post my research on this thread when I am done.
Sam Colalillo
low 9's w/ a 109
- Joined
- Jan 12, 2005
NHRA a rules for a roll bar state the O.D. of the tubes must be 1.75 inches and they allow a person to use a thinner tube if using chrome moly tubing. When using mild steel it must have a .118 inch wall thickness, and chrome moly is .083 inches. The weight of both materials is the same but obviously because the wall thickness of the chome moly is thinner, it will be lighter. How much lighter, well here is what I figure:
Area of a circle = 3.14* Radius squared
Volume of a cylinder = Area * length
Density of steel = .2840 pounds per cubic inch
Mass = Density * Volume
This is how I figured out the Area of the two different wall thickness roll bar tubes. I determined the values for a solid 1.75 diameter tube then subtracted the area of the hollow center section of the tube.
1.75 Outside Dia./ 2 = .875 out side radius of tube.
1.75-(.118*2) = 1.514 Inside Dia. of a 1.75 Dia. Tube with a .118 wall thickness
1.514/ 2 = .757 inside radius of .118 wall thickness tube.
1.75-(.083*2) = 1.584 Inside Dia. of a 1.75 Dia. Tube with a .083 wall thickness
1.584/ 2 = .792 inside radius of .083 wall thickness tube.
Area of a 1.75 Dia. Tube with .118 wall thickness
Area of the O.D. minus the area of the I.D. = Area of the .118 thick hollow tube
(3.14* .875 squared) – (3.14* .757 squared) = .604689
Area of a 1.75 Dia. Tube with .083 wall thickness
Area of the O.D. minus the area of the I.D. = Area of the .083 thick hollow tube
(3.14* .875 squared) – (3.14* .792 squared) = ..433455
2.404063-1.970608=.43355
Next I am just going to figure out how much a foot long piece of each tubing weights:
Volume of a 12 inch long 1.75 Dia. Tube with .118 wall thickness
Area determined from above equations * how many inches long = cubic inches
.604689 * 12 = 7.256268
Volume of a 12 inch long 1.75 Dia. Tube with .083 wall thickness
Area determined from above equations * how many inches long = cubic inches
.433455 * 12 = 5.20146
Weight of a 12 inch long 1.75 Dia. Tube with .118 wall thickness
Density * volume = mass
.284 lbs. per cubic inch * 7.256268 cubic inches = 2.06078 pounds
Weight of a 12 inch long 1.75 Dia. Tube with .083 wall thickness
Density* volume = mass
.284 lbs. per cubic inch * 5.20146 cubic inches = 1.477215 pounds
Difference in weight
2.06 – 1.48 = .58 pounds
Now we know a one foot long piece of chrome moly tubing is .58 pounds lighter than a one-foot long piece of mild steel tubing.
I quickly measured that it is going to take approximately 35.5 feet of tubing to do my 6-point roll bar.
Weight saving would be roughly;
35.5 * .58 = 20.59 pounds lighter if I use NHRA approved 1.75 diameter chrome moly tube with a .083 wall thickness as opposed to mild steel tubing with a thicker .118 wall thickness.
Area of a circle = 3.14* Radius squared
Volume of a cylinder = Area * length
Density of steel = .2840 pounds per cubic inch
Mass = Density * Volume
This is how I figured out the Area of the two different wall thickness roll bar tubes. I determined the values for a solid 1.75 diameter tube then subtracted the area of the hollow center section of the tube.
1.75 Outside Dia./ 2 = .875 out side radius of tube.
1.75-(.118*2) = 1.514 Inside Dia. of a 1.75 Dia. Tube with a .118 wall thickness
1.514/ 2 = .757 inside radius of .118 wall thickness tube.
1.75-(.083*2) = 1.584 Inside Dia. of a 1.75 Dia. Tube with a .083 wall thickness
1.584/ 2 = .792 inside radius of .083 wall thickness tube.
Area of a 1.75 Dia. Tube with .118 wall thickness
Area of the O.D. minus the area of the I.D. = Area of the .118 thick hollow tube
(3.14* .875 squared) – (3.14* .757 squared) = .604689
Area of a 1.75 Dia. Tube with .083 wall thickness
Area of the O.D. minus the area of the I.D. = Area of the .083 thick hollow tube
(3.14* .875 squared) – (3.14* .792 squared) = ..433455
2.404063-1.970608=.43355
Next I am just going to figure out how much a foot long piece of each tubing weights:
Volume of a 12 inch long 1.75 Dia. Tube with .118 wall thickness
Area determined from above equations * how many inches long = cubic inches
.604689 * 12 = 7.256268
Volume of a 12 inch long 1.75 Dia. Tube with .083 wall thickness
Area determined from above equations * how many inches long = cubic inches
.433455 * 12 = 5.20146
Weight of a 12 inch long 1.75 Dia. Tube with .118 wall thickness
Density * volume = mass
.284 lbs. per cubic inch * 7.256268 cubic inches = 2.06078 pounds
Weight of a 12 inch long 1.75 Dia. Tube with .083 wall thickness
Density* volume = mass
.284 lbs. per cubic inch * 5.20146 cubic inches = 1.477215 pounds
Difference in weight
2.06 – 1.48 = .58 pounds
Now we know a one foot long piece of chrome moly tubing is .58 pounds lighter than a one-foot long piece of mild steel tubing.
I quickly measured that it is going to take approximately 35.5 feet of tubing to do my 6-point roll bar.
Weight saving would be roughly;
35.5 * .58 = 20.59 pounds lighter if I use NHRA approved 1.75 diameter chrome moly tube with a .083 wall thickness as opposed to mild steel tubing with a thicker .118 wall thickness.
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