TRip Trip Anthony (162 posts) Registered: 08/18/2009 01:16AM Main British Car: 1980 TR7 performance 4 cyl |
TR7 hoop roll bar how to?
Hello everyone, when I have learned how to weld effectively, I would like to design, fabricate and install a double hoop roll bar system for my TR7. Does anyone have any information about the right way to build one and where it has to mount in the car?
I'd like it serve several purposes. 1. roll over protection 2. structural chassis stiffening 3. side impact protection 4. aesthetic value It's not intended for race application. Just general street. Also, what grade of steel should be used? I believe that seamless mild steel tubing should be used. Am I correct? And be "mandrel" bent. I'm not too sure I understand what is meant by mandrel bent and how to go about doing that, though. Thanks Trip |
WedgeWorks1 Mike Perkins Ellicott City, Maryland (460 posts) Registered: 07/06/2008 08:07AM Main British Car: 1980 Triumph TR8 3.5 Litre Rover V8 |
Re: TR7 hoop roll bar how to?
Wow not intended for racing applications with the requirements you have.......thats so not right! Your 3/4 the way there at thsi point with your plan.
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DiDueColpi Fred Key West coast - Canada (1366 posts) Registered: 05/14/2010 03:06AM Main British Car: I really thought that I'd be an action figure by now! |
Re: TR7 hoop roll bar how to?
Hey Trip,
Mike's right. You're almost there for a race cage. Check out the SCCA rule book on their website for roll cage specs and diagrams. Other designs are available but I consider these to be a minimum and a good choice for a street car Cheers Fred |
my only advice is
please make each loop has a rear brace behind it. I have seen them flop over and the guy got killed anyways... If you can go to the track and talk to some people with them installed.
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Bill Young Bill Young Kansas City, MO (1337 posts) Registered: 10/23/2007 09:23AM Main British Car: '73 MG Midget V6 , '59 MGA I6 2.8 GM, 4.0 Jeep |
Re: TR7 hoop roll bar how to?
Trip, use mild steel DOM (Drawn over Mandrel) tubing. You can check with the SCCA rule book, tubing size and thickness required varies with the weight of the car, but for your purposes I'd suggest at least a .125" wall thickness and no smaller than 1 1/2" OD. Mandrel bending is not required, but the proper type of tube bender that offers the correct support to the tube is needed to get a nice smooth bend without collapsing the tube. In most cases you'd probably need to contact one of the race shops in your area to find someone who could bend the material to your specs. Bending to a tight 180 degree U isn't easy on most benders, so you might have to settle on a modified design using two 90 degree bends with a small flat area between. As already mentioned make sure you install some type of diagonal brace in each hoop and a rear brace as well. As for mounting ideas check out the photos on the Boss Frog web site. [www.bossfrog.biz] Note that where the bar mounts to sheet metal the mounting plate is very large and will have a similar plate on the opposite side of the panel.
Edited 1 time(s). Last edit at 10/07/2010 10:29AM by Bill Young. |
roverman Art Gertz Winchester, CA. (3188 posts) Registered: 04/24/2009 11:02AM Main British Car: 74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L |
Re: TR7 hoop roll bar how to?
Trip, "Auto Power" in San Diego, CA. Makes an "approved" single hoop bar. They have been making them for decades. I haven't installed mine yet, so no installation story-yet. Maybe mod a bar from MGB or Jensen Healy / $50. up, in the used market. Good Luck, roverman.
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TRip Trip Anthony (162 posts) Registered: 08/18/2009 01:16AM Main British Car: 1980 TR7 performance 4 cyl |
Re: TR7 hoop roll bar how to?
Hello everyone, thank you for the honest reality check.
I'm definitely not looking for a racing roll cage although I can see how it would start looking like one. I guess the end result would be similar whether for street or race. Thanks for all your advice. Trip |