The 24 Hours of Lemons Forums → Lemons Newcomers → Main Hoop Diagonal Direction?
Does it matter which direction the main hoop diagonal goes? The "how not to fail" tech images show it going from driver's top to passenger bottom. Can it go passenger top to driver's bottom?
I'm not sure if that's allowed but I have to ask; Why?
In a rollover that impacts the left side of the car; the drivers side; wouldn't you want that diagonal supporting the main hoop. It will keep the roof from coming down on your head!
In fact I have see many roll hoops with an "X" in the plane of the hoop. It adds to the total stiffness of the cage as well.
I always have them with the top over the driver, trying to triangulate as much as possible right over the drivers head. If you go the other direction you lose that protection
I'm not sure if that's allowed but I have to ask; Why?
In a rollover that impacts the left side of the car; the drivers side; wouldn't you want that diagonal supporting the main hoop. It will keep the roof from coming down on your head!
In fact I have see many roll hoops with an "X" in the plane of the hoop. It adds to the total stiffness of the cage as well.
Curious about this as well. Only reason I could see for it is if it's right hand drive the I would definitely do it the other way.
You want the higher end of the diagonal to be closest to the driver, unless you do an X pattern (which I should have done, since we have a center driving position...).
I've seen cars with the diagonal over the passenger pass tech.
If you are worried about helmet/seat clearance because you need to rake the seat angle back, put the seat in and then put the diagonal on the roof of the halo as close to the corner above the driver as you can. 6" away is ok.
Also in my unprofessional opinion, If you still feel you must put the diagonal at the top on the passenger side of the hoop, consider putting in a diagonal on the backstay plane that starts at the driver's hoop corner /driver side backstay node and goes down to the passenger's backstay spreader plate. (so when you are looking through the rear of the car towards the front the backstays look like a capital N.
Thanks all. This was a visualization issue for me. I couldn't see how the 45 would allow for the shoulder harness bar if it started above the driver. Seemed in our car that it was going to cut right through where the harness bar would go. Now that we have the seat in, it's obvious that this isn't an issue at all so it will start above the driver's head. Thanks for the input!
The harness bar can attach to the diagonal.
As mentioned above, we placed our diagonal from driver's to passenger side. However, it starts just below the first bend from the top of the hoop. Top of the diagonal is about 3" from the top of the hoop (where the backstays meet). I reached out to Mr. Pagel for input, but haven't heard back. I know he's busy, so I wanted to put it to the group for input on whether this will represent a tech failure or not. We are coming to Gingerman and of course running short on time, of course. The rules are silent on where the diagonal starts, but as I look at more and more pictures, most seem to start at a higher point. We have tried to follow every rule to the letter. We know that some things can be fixed on site if there is a tech failure, but we really don't want to do that. We are making every effort to come to tech having followed every rule. Any input would be appreciated.
pic here:
https://drive.google.com/file/d/0B58Dlt … sp=sharing
The short answer on the first question is - it doesn't matter which way the diagonal bar goes.
From the picture I cannot see the highest point on the main hoop. The highest point on the main hoop to the top of the rear stay should not be greater than 6 inches.
The 45' rule is less firm than being over six inches delta on the highest point on the main hoop.
ALSO, if I were asked, I'd advise a well bent tube from the main hoop center to the halo center make it hug the roofline. This will increase the overall height for the broomstick test. In the photos it looks like there is a little extra room that could have been used to allow for taller drivers.
Good luck on your build. It looks nice.
apparently, John is sipping mai tais in Canada, or whatever it is they sip up there.
Email Jeff Glen from Lemons HQ. He's the other guy (before it gets to Jay) to give input on tech-related stuff.
jeff@24hoursoflemons.com
Then of course Jay himself
jay@24hoursoflemons.com
Thanks Spank and NSF. After a bit of restlessness, I'm feeling a little better. I know "what other series do" is never an acceptable answer here, however some more Internetting suggests to me that putting main hoop diagonal where we did is commonly acceptable to do what it's intended to do - keep the hoop from changing into a parallellagram. We have a dash bar and are planning to add an anti-bow bar, extending the harness bar across the car. NSF - yes, we are looking into adding the tube from main hoop to front hugging up into the roof as you suggested. We meet the technical 2" requirement - tested with the equivalent of a broomstick, but figure it can't hurt to add a little more. I will give John a couple of more days, and then will reach to Jeff or Jay. I hate to email everyone and have them all giving me answers - would rather bother just one of them than all. Oh, and NSF mentioned top of hoop to backstay 6" rule. We are at 3" - so good there. Main hoop is parallel across the top, no bow.
Thanks again!
Thanks Spank and NSF. After a bit of restlessness, I'm feeling a little better. I know "what other series do" is never an acceptable answer here, however some more Internetting suggests to me that putting main hoop diagonal where we did is commonly acceptable to do what it's intended to do - keep the hoop from changing into a parallellagram. We have a dash bar and are planning to add an anti-bow bar, extending the harness bar across the car. NSF - yes, we are looking into adding the tube from main hoop to front hugging up into the roof as you suggested. We meet the technical 2" requirement - tested with the equivalent of a broomstick, but figure it can't hurt to add a little more. I will give John a couple of more days, and then will reach to Jeff or Jay. I hate to email everyone and have them all giving me answers - would rather bother just one of them than all. Oh, and NSF mentioned top of hoop to backstay 6" rule. We are at 3" - so good there. Main hoop is parallel across the top, no bow.
Thanks again!
I email everyone together, you know, transparency.
apparently, John is sipping mai tais in Canada, or whatever it is they sip up there.
Probably a combination of Molson lager and maple syrup, garnished with a side of poutine.
Spank wrote:apparently, John is sipping mai tais in Canada, or whatever it is they sip up there.
Probably a combination of Molson lager and maple syrup, garnished with a side of poutine.
The Canadian Cosmo!
The 24 Hours of Lemons Forums → Lemons Newcomers → Main Hoop Diagonal Direction?