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Chris Alston Roll Cage


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Guest Anonymous

I just got back a while ago from Chris Alston's chassisworks. Picked up a 8 point rollcage. It has the upper side roof bars that bend down to the floor by the dash as well as the straight side bars. Attached is a photo of the loop just set in the car to see how it fits:

 

AUT_0080.JPG

 

More on the installation when I get to it.

 

Regards,

 

Lone

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Guest Anonymous
Originally posted by 73BOTIZ:

Lone,

Does the Alston main hoop fit into the seat belt pockets like my S&W, or does it mount above it?

Looks good,

Mike D.

Mike here's a photo, its not exactly in the pocket, more forward and outboard as you can see.

 

Keep in mind this is just set in there, and behind the rollbar and keeping it from going back I have some seatbelt/shoulder harness retractors that I need to rework or get rid of (better yet) and replace with racing harnesses.

 

AUT_0083.JPG

 

Regards,

 

Lone

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I have the S&W 10 point cage in my 72' it does have the pockets for the seatbelt retractors and the main hoop fit right into them which for me was a problem. When you purchase the kit it has 6" by

6" steel plates that should be welded down then the tubing for the cage is welded to the plate... that 6" plate does not fit into the retractor pocket. I welded the plate over the top of the pocket making it like the earlier 240's that did not have the pocket, using a protractor I was able to cut the bottom of the main hoop to the correct angle to weld to the plate and therefore set the main hoop a little higher in the car.

 

If you want to be sure that your cage does not punch through your car in the event of an accident I would recomend that you use the 6" by 6" plates.

 

Dragonfly

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Originally posted by katman:

Remind me again what the objective is of this exercise? To get a mount for race belts? To go racing? To look like we're going racing? :confused:

I won't be racing. I'm concerned about getting slammed into while rolling through an intersection. I plan to drive the car daily in southern California (which can be dangerous,) and my 71 was not built to modern crash standards. I think most of the guys here are in the same boat, so your line of questioning is inappropriate.
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Guest Anonymous

The reason for the exercise is a V8 Z that I'd like to stiffen up. If the car ends up looking raced out, thats ok, we drive with people on the street far crazier than the pro's that normally drive with roll cages. :D

 

Regards,

 

Lone

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Originally posted by Oltmann:

so your line of questioning is inappropriate.

What's inappropriate about asking what your objectives are for this cage? Are you insulted somehow by that question?

 

If your objective was to look like a racer then that cage will accomplish that. If it is to mount belts then it will accomplish that. If it is to stiffen the chassis then yes it will add stiffness, albeit very inefficiently. If it is to go racing then it is woefully inadequate. If it is to protect your head in a rollover then it won't. If the objective is to save your legs in a T-bone from somebody rolling through an intersection it won't do that either. I was just wondering what the objective was for installing a poorly designed and overly heavy (in the case of chassisworks) roll cage in a car. Seemed valid AND "appropriate" to me.

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So, if an 8 point rollcage won't be adequate for racing or crash protection, what should we use, 10 point, 12 point, 18 point?

 

Are your comments regarding this endeavor related to the use of an 8 point cage (vs. something else?), or are you besmirking the quality of materials employed in this particular brand of cage? You haven't made this clear, nor have you offered alternative suggestions (which in any event, would most likely be lost on Lone as he's already bought the chassisworks product).

 

I suspect that Oltmann's reaction was sparked by the phrasing and tone of your post. It didn't seem to be intended to help anyone out. At least, it didn't to me...

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Jeromio has it exactly right. You seem to be glad to criticize us, but you have yet to contribute anything substantive to the conversation.

 

There are a couple of us sitting here with these cages waiting to be installed. We have explained what our goals are. Tell us what you think we should do.

 

I don't really care about looking like I'm going racing, I care about peace of mind.

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I tend to agree with Katman a bit on this one. It does apear that the load paths on most of the store bought cages are not to good. In there defence, however, if you get the load paths right then it really becomes a race car and is a real pain to get in and out of. With a little extra work these cages can be made better and should be seen as a inexpensive place to start. The local racing rules here say that we only have to run one diagonal bar in the back and doesnt worry if it goes fron the roof to the strut or the roof to the floor. I would guess that the roof to the floor is best in a roll over. If you look at the cages in a lot of the world rally cars, you will find that a lot of them dont have roof to floor diagonals. I think this might be more for space, but in saying that, they are some of the stiffest cars out there. And safest.

Anyway, good on you Lone. Its about time you caged the beast. :D

Have a look around at some of these cages; http://www.e30m3performance.com/tech_articles/cage_symposium/cage_symposium.htm

 

A couple of small canges and a little extra tube will make it work better.

 

Cheers

 

Douglas

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Okay, now we're getting somewhere. That's what we are all looking for: useful information and discussion.

 

I don't think any of use here on this forum want anything on our cars strictly for appearances. In fact, I would say that the majority would rather hide much of the performance features if at all possible.

 

That m3 site has some really excellent info on cages. I especially liked this pic:

side_impact.jpg

 

That looks like a really good idea. Rather than strictly protecting the compartment, it absorbs the force.

 

FWIW, for my own cage I've bought some 1 5/8 inch DOM tubing. I'll be doing plenty of research before I begin. One of my priorities is keeping the car usable as a driver. Down the road (perhaps when I can afford a C5 ;) ), the car may become strictly a racer, but for now I want to drive it on the street. So a balance between structure, safety and ease of use (entry, egress, passenger space) must be achieved.

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NHRA won't approve a cage unless the main hoop is at least 0.120" thickness DOM mild steel. Chromoly is a different story, but if you're using 0.095 mild steel, the cage won't be legal. Unfortunately, most 0.120 mild steel DOM tubing is actually 0.118-0.119! Some NHRA tech inspectors will fail that! I can't claim first-hand knowledge, but I have heard of people spending $2000+ on custom cages with 0.120 tubing, only to get their cars failed. This is why it's something of an industry standard to use 0.134" tubing for the cage main members. My car has 0.134" for the main hoop and various other parts of the cage. Strut tower bars, main backbone, and the various diagonals range from 0.065" to 0.120", to save weight where possible.

 

I agree that some folks are a bit too eager to install roll cages in street cars. Yes, even mediocre cages do offer some measure of safety, but a poorly designed cage is almost certainly more trouble than it's worth - and can lead to a false sense of security. In my opinion, there is no substitute for X-bars to side impact protection - yet few people would go to the extreme of welding in permanent X-bars, to hard points welded to the unibody. "Doing it right" rapidly spirals into the construction of a bumper-to-bumper tube frame. That's what happened to me. This is fine, I suppose - except that the result isn't what one might seriously call a daily driver.

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