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Triumph TR6 - Single Hoop Roll Bar
I'm still looking for a single hoop roll bar; one that's behind the driver's seat only, like in a AC Cobra. I had one in my TR4A and a buddy had one in his MGB so they were comercially available at some point in the '70's but I've searched the web and cannot locate one. Does anybody out there know where I can get one of these. BTW, the top of the hoop on both of these bars was chrome plated but black would be just fine. Thanks.
Bob '76 - 6
|Good morning Bob|
i was thinking of starting a thread, to see if i could
get enough guys in Ont. to make our own single hoop.
bought a full roll bar off a tr6 owner last year,
and now that my 74 is about to see the road again ive
decided to sell the full hoop (just don,t like the way
|I was going to bend up a full bar using a custom bender a friend and I built years back. The material will be 1.75 X .095 ERW with a bend radius center of about 7". What is the advantage to a single hoop verses a wider bar that protects both occupants?... I can hear my wife now; "you've got nothing over here for me and you're not protecting anything of value over there"! Nevertheless, if there was sufficient interest I am sure we could bend up a few sets with the appropriate mounting feet MIGed in place and perhaps even powdercoated in (semi) gloss|
It sure looks like the only way to get one is to have it fabricated. A Calgary company said they'd do it if I provide an engineer's drawing but finding an engineer willing to take it on is a problem. Rob: as far as protection is concerned, my web surfing indicates that any roll bar, full width or single that will fit under the raised convertible top will not meet SCCA standards and likely won't help much in a rollover. I don't like the look of the full bar but the single hoop was unique, looked great and drew a lot of comments in my TR4A. Two guys were looking at my 4A in a K-Mart parking lot one day; one guy says,"what's that chrome pipe for"? The other guy says, "it's where he puts the gas in you dummy"! It's not about protection Rob; it's about preference. Jeez, after all the work on the 6 I'd probably prefer not to survive the rollover anyway. Too much work to do over.
'76 - 6
|The engineering drawing position is probably a liability issue. If the drawing is signed off by a licensed PE, then the liability is with the PE and not with the fabrication shop provided that they build the part to the print.|
I would think that in turn, you may have a problem finding a PE to do the design if it is identified as a roll bar. The second you call it a roll bar, you have indicated that it is inteded for occupant protection. It would have to be positioned as some sort of decorative accessory. If you have access to welding equipment or know someone who can do the welding for you, you can try a tube bnding shop and have them bend up a 180 degree section, then shark mouth the mount braces, fabricate the mounting feet and weld all of it together. In other words, if all you are buying is a bent piece of tubing, what do they care about how it is used?
As for the roll bar requirements of the SCCA GCR, you are correct. Unless it for something like one of the old Datsun 1600/2000 roadsters that looked like some variation of a giraffe cart when the top was up, a roll bar built to GCR requirements will not allow you to use the top. Second, the GCR does not allow just a roll bar, but requires a cage. You would have to have two hoops, one main and one forward with bracing fore and aft on both within a prescribed range of angles, along with a diagonal on the main hoop. Diameter and wall thickness requirements are defined by vehicle weight. Only steel DOM tubing may be used.
|Bob and Steve, you're so right about not wishing to survive the roll over! I think I may have seen your TR6 on a members picture site.... is it white? I too have a '76 (com# cf75639UO with the 'O' added)and will eventually be painting it white..... currently still in the take-apart stage. I should send you some pics of my disaster...er rustoration..er...|
I totally agree with Steve re the hoop specs and well know the legalities and sanctioning standards that apply to this sort of part. We designed and built racing go-karts for years in my metal/design program... and won many provincial and several national titles with our home built junk! I think I will make twin single hoops as they do look terrific and will fit into my powdercoating oven... unlike the full width model. I was thinking to make them slightly asymetrical:
l l the driver's side...
hiho hiho its off to weld I go... rockers today after the patching. UGH!
Cheers to All, Rob
Yes, it's white and still hasn't grown on me enough to finally repaint it that color. (Sorry Charlie!) Yep, I'm the guy leaning on the '76 TR6 (CF53465U) with the guardrail and the scenic rolling hills in the background. Mallard Blue/Green may be the new color. I like the idea of the double hoops better than the full straight bar. Mazda Miata suppliers market what they refer to as a "style bar" (for legal reasons I guess)that has two hoops and they are pretty nice. An added bonus appears to be structural rigidity because they are fastened side-to-side versus welded to the floor. Those guys also indicated that they would fabricate a style bar for the TR6 but I don't want to spend a small fortune while they perfect their research and development.I think I'll take Steve's advice and have somebody "bend some pipe" into shape for me and get feet welded to it.
the 106 mallard blue/green is a great colour and one
you don't see to often,my 74 has been repaited 106
my wife was hopeing i choose either deft or royal blue.
my 70 was 32 signal red and even though i thought it was a great colour then, i prefer the blue now.
your idea of two single hoop with chrome tip like the
miata would look great and you could still attach a
sheet of plexie glass behind,to block some of the back
draft,which is why i bought the full hoop in the first
place ,but that another topic coverd in the archive.
If you have trouble finding a fabrication shop to build that hoop, and aren't concerned with SCCA requirements, I remember a friend taking his TR6 to a muffler shop in the early 70's, they measured it all up and built the 'roll' bar right there. Welded the mounting plates on, and he painted it and bolted it in. Obviously wasn't the SCCA approved one, but it served the purpose. You have to be creative in those small Eastern Oregon farming towns! BTW, they did use a heavier gauge metal than your standard exhaust pipe!
|I was lucky enough to find an original one of these single-roll bars describd above about 5 years ago. It was (and is) in great shape.|
At the time there were 2 to choose from, so I took the better looking of the 2.
I was told that these bars were circa 67 - 69, and were originally on TR4's.
Recalling the install, the furthest forward - driver side bolt was a real tight fit under the car.
|Sorry, forgot to sign-in prior to posting above comment.|
|Found the info where I purchased it.|
British Classics, Simon, 905-472-5321, Markham Ontario.
PS. The soft top needs a wee bit of assistance when going up or down over the top of the bar.
|TRGB has them. Company is in England. It has attachments for racing harness also. They look good. Saw them in a magazine. They have a website. Try www.trgb.com.|
description: Hooped roll Bars TR4-6
Price: 145 pds.
In their ad I also saw a nice push button starter switch that fits perfectly in the dash in place of the dimmer rheostat. I think I will order their catalog for 3 pounds. You can see a picture of the roll bars on their home page. Its on the car on the verge of tipping over when you first log on to their website.
|Thanks Rob, Steve and Peter:|
I knew they were out there somewhere. I looked at TRGB and downloaded their catalog software but no pics. Their site is www.trgb.co.uk and their opening screen shows a TR4 with twin hoops. Hey, Peter, any chance of getting a good pic of your bar, possibly with the seat folded forward? The old TR4 pics I have don't show any detail on the bar. Rob, bending up a few sets sounds like a good idea but we'd need to all agree on a design. Also, the bar in my TR4A did not interfere in any way with the soft top. And send the pics of your "rustoration" to Charlie Ballard & he'll post for all to see.
Cheers and Happy Easter to all you TR6 drivers,
'76 - 6
You must have sent your thread while I was still composing mine. Were you able to view items on the TRGB site, as I was not? I downloaded their package but all I got was a DOS program.
All I got was a price list. I saw their ad in a U.K. magazine about Triumphs. One of the feature cars in the magazine was a TR5 with the roll hoops from TRGB. It looked fabulous. I wish I bought the magazine. I saw it earlier this month at a book store in CA.I remember noting that the roll hoops had attachments for shoulder harnesses on each side. I need to order their catalog.
I have a couple of pics which can be found at http://www.streamload.com/johnston21
I'll snap a couple more of the bar mounts next time I "roll it out."
I own a Tube bender, and a powder coating line. If someone supplies the plans I run a set.
|One potential solution with respect to design is to use the CASC / SCCA regs. |
If the hoops are designed to be robust enough to handle the consequences at racing speeds, then one would think it should be able to handle a single vehicle roll over accident.
Please be aware that all bets are probably off if you end up "dancing" with a big SUV or something larger.
According to my 25 year old CASC regs for a vehicle with a race weight of over 2500 (lbs one would assume), then the hoop and braces (fore/aft & diagonal) should be constructed of at a minimum 2.25" x 0.120" mild steel tube(seamless, ERW, or DOM) with minimum 3/16" thick mild steel mounting plates. Minumim 3/8" grade 5 or aircraft bolts recommended for mounting.
One thought on the driver only hoop design (with a full arc at the top), is that it might be less likely to collapse (or lozenge) than a full cockpit width one without a diagonal brace.
Better than nothing for the passenger, but then do you really want to raise that issue in the first place?
|Leonard G Middleton|
That is THE BAR my friend! Thanks. Exactly the same as the bar I had in the TR4A and my buddy had in his MGB, right down to the "checkered flag" tape where the chrome finish meets the black. That is what I want and a good pic from above rear and probably views from either side would be enough for me to get the fabrication arranged. Jeez, is that ever nice to see after all these years. It just has that little something that the full bar doesn't add to the car. Flash??
'76 - 6
I'll get the requested pics up in the next day or 2 (max.)
|TRGB has just updated their website. Look under "Special Offers" and you will see pictures of their roll hoops along with the race harness to go with it. They also offer a nice lightweight steel flywheel and have pictues of the starter button that fits in the dash.|
Thanks for the pics. I can see clearly what needs to be done on a fabrication. From what I can remember, mine had the long side-to-side bottom bar removed and just had "feet" on the ends but it is definitely the same bar. Mine must have been modified a little. I'm going to try your contact but after 5 years it's unlikely he'll have one but you never know your luck. If anybody out there has a bar like Peter's for sale I am definitely interested.
|This past Friday, I was on my way to pick-up some TR6 parts when I saw a car transporter carrying 2 new Dodge wagons and a TR6 (not in the greatest shape). Anyway, lo and behold the TR6 had what appeared to be an original Single-Hop Roll Bar in it (checkered tape and all).|
I hope you followed that transporter! There's gotta be a single hoop bar somewhere out there for sale.
Malcolm in Ontario - if you have enough guys interested to make fabrication of the single hoop bar viable I would definitely be interested. Chrome top would be nice but I would settle for black painted.
just got back from Ancaster flea mkt,saw a single hoop
in a mgb as well as a pair of chrome tubes in another
which were strickly cosmetic.
What i saw which may be useable were a pair in a miata.
After about 4 yrs i will have my car back on the road
in the next few days,and when i go to some of the car
club function over the course of the summer i"ll try and drum up some interest, as Marcello has a tube bende
and a powder coating line we may be able to get something going .
This thread was discussed between 26/03/2005 and 18/04/2005
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