Roll cage door bars, knee bars and pillar gusset questions. (Answers in first post.)
#16
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Originally Posted by Bryan Watts
1) Search for thread.
2) Copy and paste address from the address bar of your browser:
https://rennlist.com/forums/racing-and-drivers-education-forum/259343-cage-questions-for-de-car-possible-club-racer-in-near-future.html
2) Copy and paste address from the address bar of your browser:
https://rennlist.com/forums/racing-and-drivers-education-forum/259343-cage-questions-for-de-car-possible-club-racer-in-near-future.html
You must be running an old browser. The new IE does not display the actual URL of the thread anymore. it just displays http://forums.rennlist.com/
Maybe there's a setting I need to adjust.
#17
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Originally Posted by complexx
You must be running an old browser. The new IE does not display the actual URL of the thread anymore. it just displays http://forums.rennlist.com/
Maybe there's a setting I need to adjust.
Maybe there's a setting I need to adjust.
Regardless, you can still right-click on any link and "Copy Shortcut" or take a look at the Properties to get the full address.
#18
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https://rennlist.com/forums/showthread.php?t=259343
Ohh, that worked. Excellent! Thanks.
*Edit
There used to be some great images (including FEA analysis) in this thread, but they have been lost. Hopefully you can still get something out of it.
Ohh, that worked. Excellent! Thanks.
*Edit
There used to be some great images (including FEA analysis) in this thread, but they have been lost. Hopefully you can still get something out of it.
#19
Question for you guys either updating your cage or building new ones;
Since you are installing at least 2 bars ( X or NASCAR style) are you removing the door bar inside the door itself or are you leaving it there?
I left mine in but I only have one horizontal bar on my cage, (Yeah I know I'll have to upgrede it to race).
Thanks.
Since you are installing at least 2 bars ( X or NASCAR style) are you removing the door bar inside the door itself or are you leaving it there?
I left mine in but I only have one horizontal bar on my cage, (Yeah I know I'll have to upgrede it to race).
Thanks.
#20
Originally Posted by Mark in Baltimore
2) Piper is going to be deleting the stock knee bar to facilitate the cage knee bar installation and to make sure that it is far enough away from my knees if I should have a potential frontal impact. Am I allowed to remove the stock knee bar for this purpose? The PCA rules don't specifically address this deletion.
#21
As for the argument over which is stiffer, NASCAR or X-style, I can't see either being that much stiffer than the other. For structural frames, an X connected in the middle does not transfer the load as efficiently as an X which isn't connected. I don't design cages for a living, so maybe I don't know what types of loads need to be accounted for in the door bar in reference to frame rigidity wrt handling. I'm an engineer, just not for race cars
Which is safer? I'd probably go with the ones that go on the cars that crash all the time
I have heard rumblings from the NASA group I know that NASCAR style bars will be required on at least the drivers side in the future.
Which is safer? I'd probably go with the ones that go on the cars that crash all the time
I have heard rumblings from the NASA group I know that NASCAR style bars will be required on at least the drivers side in the future.
#22
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I was told the x bar was safer. The nascar bars would theoretically allow more bar to intrude into the driver's zone. I don't know but I was worried as my Kelly-Moss prepared (90's) car has the x and I was worried about needing a new cage/bars because of all of the hubub about nascar bars. At my NASA annual tech they told me my car was fine, no need to worry.
#23
Originally Posted by Bryan Watts
Ultimately, I'd do an X on both sides and the use some thinner wall (read: lighter) bar to create a "crush zone" outside of the X on the driver side...especially since you aren't running in an unlimited weight class. You'll have the crush bars to absorb the impact and the X to stop the impact before the crush bars can bend into the driver compartment.
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Do you have pictures of how such a set-up with crush bars would look like? I have never seen such a arrangement. Also, if you wanted a crushbar could'nt you just leave the DOT stock dorr bar in place and then run the standard "X" safety bar as part of the cage and be done with it?
#24
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Originally Posted by fatbillybob
Do you have pictures of how such a set-up with crush bars would look like? I have never seen such a arrangement. Also, if you wanted a crushbar could'nt you just leave the DOT stock dorr bar in place and then run the standard "X" safety bar as part of the cage and be done with it?
Also interesting to note is that BMW went so far as to pull the A-pillar bars down and back from the A-pillars and the B-pillar bars down in order to lower the CG of the car for the GTR chassis that ran in ALMS and Grand-Am Rolex.
#26
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Bryan, Is it just me or do those NASCAR bars look like they'll become projectiles in a T-bone. Isn't that door frame just thin sheet metal that they're welded to?
#27
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I haven't seen the car up close, but one could easily assume that the bars tie back into the cage or significant portions of the chassis. Obviously welding bars directly to some thin sheet metal wouldn't pass any sort of tech inspection. They just go through the sheet metal you see rather than attach to it.
Obviously, got a club racing car, you could need to do the bars a bit differently, creating the "NASCAR" bars as they are usually done on a club car and then adding in the X-brace in a flat plane between the A and B pillar downtubes.
Obviously, got a club racing car, you could need to do the bars a bit differently, creating the "NASCAR" bars as they are usually done on a club car and then adding in the X-brace in a flat plane between the A and B pillar downtubes.
#28
Notice the picture of the bar or perforated sheetmetal supporting the lexan front window in Bryan's post #24. Does anyone know where you can buy that stuff or is it always custom made? Thanks for posting Bryan.
#29
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Thread Starter
I'm sorry it's taken so long for me to get back to my thread. I have to find a way to pay for this cage!
BTW, I put the answers to my questions in the first post.
Nader - I just got an email back from Donna. She said that the passenger side door can be gutted. If the X bar is stiffer than a NASCAR-style bar, then wouldn't it make sense to have the same stiffness left-to-right?
Donna also said that the stock knee bar can't be removed if it is a structural part of the chassis, but my knee bar is not structural at all. I will remove the stock one and add the cage knee bar.
Mike - I have all of the cage pics you've posted here on Rennlist saved on my computer. Since my car sees all of two days on the street, at best, I'm strongly considering gutting the doors and going with NASCAR bars. I'll lose weight by deleting the window that may be added in by the NASCAR bars (Mitch estimates another 3-4 lbs more for the NASCAR bars, hardly a huge amount).
complexx - Thanks for your input. My cage builder says that not only are most sanctioning bodies going to NASCAR-style bars, but he's seen better crash results with NASCAR bars.
BTW, with a PC, right-click on a web page, go down to "Properties", highlight the address, copy and then paste the page's URL wherever you want.
Eddie - From what I've read, you can't get rid of the stock door bar, so, for my car, it'll stay in.
Todd - Thanks for the info. My stock knee bar will go bye-bye.
Jake - My cage builder says that the X bars are slightly stiffer but that there is a minimal difference in weight.
John - I understand the mechanics of a pyramidally-shaped X bar but I beleive the thinking is that in major T-bone, an X bar is going to move as much as a NASCAR bar, but the NASCAR bar has the advantage of being further away from the driver.
BTW, I put the answers to my questions in the first post.
Nader - I just got an email back from Donna. She said that the passenger side door can be gutted. If the X bar is stiffer than a NASCAR-style bar, then wouldn't it make sense to have the same stiffness left-to-right?
Donna also said that the stock knee bar can't be removed if it is a structural part of the chassis, but my knee bar is not structural at all. I will remove the stock one and add the cage knee bar.
Mike - I have all of the cage pics you've posted here on Rennlist saved on my computer. Since my car sees all of two days on the street, at best, I'm strongly considering gutting the doors and going with NASCAR bars. I'll lose weight by deleting the window that may be added in by the NASCAR bars (Mitch estimates another 3-4 lbs more for the NASCAR bars, hardly a huge amount).
complexx - Thanks for your input. My cage builder says that not only are most sanctioning bodies going to NASCAR-style bars, but he's seen better crash results with NASCAR bars.
BTW, with a PC, right-click on a web page, go down to "Properties", highlight the address, copy and then paste the page's URL wherever you want.
Eddie - From what I've read, you can't get rid of the stock door bar, so, for my car, it'll stay in.
Todd - Thanks for the info. My stock knee bar will go bye-bye.
Jake - My cage builder says that the X bars are slightly stiffer but that there is a minimal difference in weight.
John - I understand the mechanics of a pyramidally-shaped X bar but I beleive the thinking is that in major T-bone, an X bar is going to move as much as a NASCAR bar, but the NASCAR bar has the advantage of being further away from the driver.
Last edited by Mark in Baltimore; 05-04-2007 at 09:46 AM. Reason: clarity
#30
mark,
Deleting the kneebar means you have nothing supporting the a-pillers and the part of the cage that makes the front part of the box. With this bar missing you weaken the action of the door bars of any type and basically negate a lot of your side impact protection. I think you need a kneebar or a dashbar so you don't get the knees broken in a front-ender. Do a bit more research I think the structural need for this support has been discussed on other Rlist threads
Deleting the kneebar means you have nothing supporting the a-pillers and the part of the cage that makes the front part of the box. With this bar missing you weaken the action of the door bars of any type and basically negate a lot of your side impact protection. I think you need a kneebar or a dashbar so you don't get the knees broken in a front-ender. Do a bit more research I think the structural need for this support has been discussed on other Rlist threads