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The GMR
12-14-2009, 10:42 PM
https://static1.pt-content.com/images/pt/2009/12/yhst94167679943066_2085_590378-1.jpg



The challenge-
How can a simple removable joint be both strong and stealth in appearance?
<o:p> </o:p>
The Solution-
In a world of technology sometimes the simplest design works best. The GMR tube clamps are precision units that are machined with interlocking sections for strength and ease of install. They weld into the tube with the machined end then bolt together with stealth like Allen cap head screws. These units are the ultimate in strength for any removable chassis application. When complete the cap screws are recessed so nothing protrudes the OD of the original tube. The threads of the cap screws are not machined completely through to prevent rust or buildup inside the clamps.
<o:p> </o:p>
The results-
Interlocking design
Machined from 4130 Chromoly
Pocketed design for weight reduction
No through hole to prevent seizing of cap screws
Recessed Allen Cap head screws
Many different sizes available


Available online through TheGMRstore.com at the link below.
http://www.thegmrstore.com/tuclco.html


https://static1.pt-content.com/images/pt/2009/12/yhst94167679943066_2085_647524-1.jpg


Please contact us if you have any questions.

GMR LLC
562-595-5410

Jason

beep4beep
12-15-2009, 02:04 PM
what sizes are these available in and how much are they? that is so cool. Randy

The GMR
12-15-2009, 04:55 PM
Here are the sizes and prices.

2 by .120 $40
2 by .095 $40
1.75 by .120 $37
1.75 by .095 $37
1.625 by .120 $36.5
1.625 by .095 $36.5
1.625 by .065 $36.5
1.5 by .120 $36
1.5 by .095 $36
1.5 by .065 $36
1.25 by .120 $28
1.25 by .095 $28
1.25 by .065 $28
1 by .120 $26.5
1 by .095 $26.5
1 by .065 $26.5
.75 by .095 $25
.75 by .065 $25


They can be purchased online at the link above or by giving us a call.
562 595 5410

jason

beep4beep
12-15-2009, 09:48 PM
thanks for the reply. when i built my cage ,didn,t leave access to back seat area. these clamps will allow easy access and still be strong. thanks Randy

The GMR
12-15-2009, 10:12 PM
thanks for the reply. when i built my cage ,didn,t leave access to back seat area. these clamps will allow easy access and still be strong. thanks Randy



That is exactly what the picture above is from. Works great and is race proven strength. Ive had some very heavy race trucks roll with these in the structure, never any failure.

jason

67 455 Bird ragtop
12-16-2009, 10:25 AM
Would these be strong enough to be used in place of swing bar kits on BOTH down bars but still maintain overall strength and safety ???

Damn True
12-16-2009, 10:28 AM
That is exactly what the picture above is from. Works great and is race proven strength. Ive had some very heavy race trucks roll with these in the structure, never any failure.

jason

Interesting.

Have you had them pass SCCA or NASA tech?

The GMR
12-16-2009, 03:21 PM
Interesting.

Have you had them pass SCCA or NASA tech?


SCCA and NASA have not passed them to my knowledge. Many other vehicles and sanctioning body's have no issue with them. They are more then safe enough, getting them approved has proven to be more of a political issue.

jason

Damn True
12-16-2009, 03:37 PM
SCCA and NASA have not passed them to my knowledge. Many other vehicles and sanctioning body's have no issue with them. They are more then safe enough, getting them approved has proven to be more of a political issue.

jason

Not to question your engineering DD but statements like those w/o supporting documentation are pretty meaningless.

Which "other sanctioning bodies" are you referring to?

As to the "political issues", I'm not sure what you mean. I am involved in racing as a crew chief for a small team. We tend to run the bleeding edge with a number of things on our cars. Getting through tech is not political particularly where safety items are concerned. It's a matter of knowing the regulations, and being able to support the position that the modification is within them. If you know your stuff tech is a breeze. It doesn't stop people from protesting of course and how those protests are handled "could" be influenced by politics but again, if you know your stuff they won't have a leg to stand on and I have yet to see a safety related item protested by a competitor.

Have you attempted to get these through tech on an otherwise legally classed car in NASA or SCCA?

I should say that I am by no means attempting to shoot down you or your product. I like the idea and they appear to be a great looking design. I just think it's important for something as critical as this to have the blessing of people experienced in the evaluation of racing safety items. A poorly designed cage in a street/track car could be more dangerous than none at all.

I've passed the link to this thread to a friend who is a NASA tech inspector and very experienced cage builder to see what his thoughts are.

The GMR
12-16-2009, 03:47 PM
Not to question your engineering DD but statements like those w/o supporting documentation are pretty meaningless.

Which "other sanctioning bodies" are you referring to?

As to the "political issues", I'm not sure what you mean. I am involved in racing as a crew chief for a small team. We tend to run the bleeding edge with a number of things on our cars. Getting through tech is not political particularly where safety items are concerned. It's a matter of knowing the regulations, and being able to support the position that the modification is within them. If you know your stuff tech is a breeze. It doesn't stop people from protesting of course and how those protests are handled "could" be influenced by politics but again, if you know your stuff they won't have a leg to stand on and I have yet to see a safety related item protested by a competitor.

Have you attempted to get these through tech on an otherwise legally classed car in NASA or SCCA?

I should say that I am by no means attempting to shoot down you or your product. I like the idea and they appear to be a great looking design. I just think it's important for something as critical as this to have the blessing of people experienced in the evaluation of racing safety items. A poorly designed cage in a street/track car could be more dangerous than none at all.


SCORE, BITD, MDR, SNORE, ect.....

These were originally designed for off-road use. We use them because of the clean look.

"political issues", i dont even want to go there.

bottom line, its a simple product that works great, I'm not concerned about getting them "approved" at this time. In the future, maybe.

jason

Damn True
12-16-2009, 03:55 PM
Thanks for the clarification. Honestly I have no idea what the cage requirements are in any of those organizations and how, if at all, they would map to requirements in NASA or SCCA. Appreciate the follow up.

Just out of curiosity though, what would be the application for a removable cage member in a dedicated race truck?

JMarsa
12-16-2009, 04:16 PM
True,

I thought you posted in this thread:

https://www.pro-touring.com/forum/showthread.php?t=62850

Anyway...What confuses me is who actually makes these, I assumed GMR was reselling them. Meaning your questions are directed to a fabricator as opposed to the manufacturer. You still ask legit questions, but the perspective is different I suppose.

--JMarsa

The GMR
12-16-2009, 04:28 PM
True,

They are used for fuel cell mounts, front cross brace sections, removable sections for engine/ drive train, and for spare tire setups.

JMarsa,

The units that Ballistic sells are a "cheaper version" of the units we provide. They were the copy to the original.

jason

Damn True
12-16-2009, 04:34 PM
True,

I thought you posted in this thread:

https://www.pro-touring.com/forum/showthread.php?t=62850

Anyway...What confuses me is who actually makes these, I assumed GMR was reselling them. Meaning your questions are directed to a fabricator as opposed to the manufacturer. You still ask legit questions, but the perspective is different I suppose.

--JMarsa

Did I? I think it was just JP unless I missed something.

Damn True
12-16-2009, 04:36 PM
True,

They are used for fuel cell mounts, front cross brace sections, removable sections for engine/ drive train, and for spare tire setups.



jason

So not in cage members who's primary purpose is occupant protection or who's load path is directed at the cockpit?


Is the test data published? I might be missing it, but I don't see it on your website.

parsonsj
12-16-2009, 04:39 PM
It was me in the other thread.

One other question about this part: have you had any difficulties with the tubes moving as they are welded up, and causing mis-alignment?

They look like they fit with zero or just a small amount tolerance (< .010), and I'd worry about that.

jp

JMarsa
12-16-2009, 04:46 PM
JMarsa,

The units that Ballistic sells are a "cheaper version" of the units we provide. They were the copy to the original.

jason

So do you produce or resell these better units? I'm not trying to steal any thunder from a site sponsor, I think that builders need to understand what they are buying. I thought these were all the same product so I'm sure others would think the same. When comparison shopping how does one know who makes which product? I'd like to know who the OEM is if possible.

--JMarsa

The GMR
12-16-2009, 05:30 PM
So not in cage members who's primary purpose is occupant protection or who's load path is directed at the cockpit?


Is the test data published? I might be missing it, but I don't see it on your website.


In some, yes. There are a few thousand truck/ buggies with them.

No test data.

jason

The GMR
12-16-2009, 05:32 PM
It was me in the other thread.

One other question about this part: have you had any difficulties with the tubes moving as they are welded up, and causing mis-alignment?

They look like they fit with zero or just a small amount tolerance (< .010), and I'd worry about that.

jp


yes and no.

Sometimes they can be a little difficult, the process and weld pattern make a huge difference. I find that if you weld the structure first then the clamp last there is little to no issues with the fitment.

jason

The GMR
12-16-2009, 05:34 PM
So do you produce or resell these better units? I'm not trying to steal any thunder from a site sponsor, I think that builders need to understand what they are buying. I thought these were all the same product so I'm sure others would think the same. When comparison shopping how does one know who makes which product? I'd like to know who the OEM is if possible.

--JMarsa


We sell them, they are machined by our supplier.

There are several differences. The units we sell are 4130 chromoly with a larger interlocking surface area. The bolts seal the holes up, no through holes. This prevents them for seizing over time and creates a cleaner looking joint when welded.

jason

Damn True
12-16-2009, 06:09 PM
In some, yes. There are a few thousand truck/ buggies with them.

No test data.

jason

Not a useful datapoint.

The test data does not exist or you don't have it?

The GMR
12-16-2009, 06:13 PM
Not a useful datapoint.

The test data does not exist or you don't have it?


I do not have test data. If and when I decide to address SCCA or another sanctioning body again I will have everything prepared.

Is there a reason you are addressing this with me? I did not notice any word for you in the other thread related to clamps such as this.

jason

parsonsj
12-16-2009, 06:20 PM
Sometimes they can be a little difficult, the process and weld pattern make a huge difference. I find that if you weld the structure first then the clamp last there is little to no issues with the fitment. That sounds right. I used Alston clevis style parts on my last car, and that's how they recommended welding their parts too.

jp

The GMR
12-16-2009, 06:32 PM
That sounds right. I used Alston clevis style parts on my last car, and that's how they recommended welding their parts too.

jp


Yes, if you notice in the picture i posted the clamp is only tacked in and the tube is welded. I will weld the clamp last, after the entire car is together.

jason

Damn True
12-16-2009, 06:33 PM
I do not have test data. If and when I decide to address SCCA or another sanctioning body again I will have everything prepared.

Is there a reason you are addressing this with me? I did not notice any word for you in the other thread related to clamps such as this.

jason

Curiosity and concern. It's a great idea. But I would want real engineering data and the input from a respected race car builder and NASA/SCCA tech before using it in my car or seeing someone I care about use it in theirs for a removable harness bar (which I actually wouldn't have at all in a car...ever) or for a removable door bar. The latter application is something I would consider, but I would want a whole lot more information to work from beyond
There are a few thousand truck/ buggies with them.

Empirical data trumps precedent regardless of frequency. I mean one could say that since so many people have run races and survived wrecks without a HANS Device that they aren't needed. But, empirical data proves that a wreck is far less likely to cause serious or fatal injury if the driver has it.

Again, the intent here is not to slight you, or the product. I am genuinely interested in it. Due diligence on my part.

Like I said, I bounced it off of a friend who is a builder and NASA tech. I'll be sure to pass on his thoughts regarding their use in structural applications and in occupant protection applications.

The GMR
12-16-2009, 08:43 PM
Not a problem,

Due Diligence is always a good thing.


My first concern would be the quality of the weld that is holding the clamp into the tubing.

jason

JMarsa
12-17-2009, 07:09 AM
We sell them, they are machined by our supplier.

There are several differences. The units we sell are 4130 chromoly with a larger interlocking surface area. The bolts seal the holes up, no through holes. This prevents them for seizing over time and creates a cleaner looking joint when welded.

jason

Thanks for your reply.

--JMarsa

Damn True
12-18-2009, 09:26 AM
Got the feedback from my friend in NASA tech. He is among the leading builders in Nor-Cal and has been with NASA tech for ages.

Note: The following is based entirely on his viewing of the thread. It is not an official decision of NASA tech. His comments in the quote boxes. All else are my thoughts.


The standard design for joining removable cage sections is an internally butted, externally sleeved joint with 3/8" Grade 5 thru bolts - the only loading that can be applied to these bolts is double shear. A couple other points to consider:
With the removable section out of the car, there is a stub left, just as there is with a sleeved junction. The stub is an extreme hazard if pointing at an occupant.

This too is my primary concern in an application such as a removable door bar or harness bar. FWIW the more common pip-pin style junction often found in "drag style" removable door bars or in some companies removable harness bars is as bad, if not IMO worse.




Note that the main hoop and diagonal are to be continuous, no junctions. Bolt in roll cages have been accepted in race cars using properly fabricated sleeved junctions on the halo, windshield bar, and door bars. Autopower, for example, does not offer a removable harness bar in their race bolt in roll cages.

A bolt in install in a HPDE car would be given *some* amount of leeway given the dual nature of the car. The chance that significant bending forces would be applied to a harness bar are slim, but the consequences potentially lethal, so I don't recommend it.

No on the door bar. Long span, there specifically to absorb bending loads, failure points a broken tube right at an occupant. Just say no.


Can't add much to this.


The mechanical tube unions look like a reasonable joining method for accessories where the compactness is needed, and failure of the joint will not compromise a critical component.

You mentioned that your most common application is for removable crossbars for ease of maintenance around engine and drive train parts, fuel cells, spare tire mounts and the like. Seems to me that this is a brilliant solution for this type of application.


I challenge their statement "the ultimate in strength for any removable chassis application", compared to a sleeved union. Put a bending load on a tube attached to that junction - if the tube bends before the fasteners fail I'll be surprised, and a tech inspector still would have no good way to verify the grade of the Allen head cap screws.

I'd love to see the test data from your manufacturer that supports this claim. Comparison vs an unmolested tube and vs an internally butted, externally sleeved joint.


Someone going to the trouble and expense to use these for their clean appearance may also want to grind the welds flush - raising more red flags in tech.

Ditto. The install, as previously discussed between you and JP seems REALLY critical on these. It's not something I would try to tackle myself. If one were to use them, I would highly recommend that they be installed by a highly qualified cage builder.