1G Roll cage seating position questions?

[SasaniFab]

So Ive decided to go through dash on the A pillars. My question for those with roll cages, when you are sitting in the seat do your shoulder stick out outside the edge of the a pillar? For instance if you take a straight edge from the edge of the bar down will it hit your shoulder? I cant understand how thats possible in this car. I have very broad shoulders and for the life of me cant see that happening. If im sitting in a comfortable position the door diagonal runs through my left arm and the a pillar follows tight against the door sill and curves in to the main hoop.

 

[FIBA M - EC17PSE]

Im talking 2g but in general the DSM chassis is very tight inside and we dont have alot of room as it is, even though i made my new seating further in i would still have the door bar just to the left of me by a few MM possibly. So in short answer yes it will likely pass through your arm area

 

[SasaniFab]

Im talking 2g but in general the DSM chassis is very tight inside and we dont have alot of room as it is, even though i made my new seating further in i would still have the door bar just to the left of me by a few MM possibly. So in short answer yes it will likely pass through your arm area

I was going to say it's not possible to make it any tighter...

 

[FIBA M - EC17PSE]

When i did my cage i knew it was already going to be tight but once a cage is in place its just so much more tighter

 

[jakelandry]

2g’s here also but yes. On my car I cut into the trans tunnel as much as you possibly can to push my seat over and I’m still under it. There’s physically no way around it.

 

[ThunderChild]

What about cutting the inner door skin some and bulging it into there, unless that's not allowed by rules when you have door bars?

 

[jakelandry]

What about cutting the inner door skin some and bulging it into there, unless that's not allowed by rules when you have door bars?

He’s talking about the overhead bars.

 

[ThunderChild]

He’s talking about the overhead bars.

Ah, misread!

 

[FIBA M - EC17PSE]

He’s talking about the overhead bars.

I think he is talking about the side bars as he askes about shoulders so my guess is arms aswel so cutting tinto the door would be a big nicer from a certain point but it wouod be better to do that idea and also lower the side bars so they dont come up near shoulder height

 

[jakelandry]

I think he is talking about the side bars as he askes about shoulders so my guess is arms aswel so cutting tinto the door would be a big nicer from a certain point but it wouod be better to do that idea and also lower the side bars so they dont come up near shoulder height

After re-reading you may be correct.

If you are talking about the door bars most sanctions will allow and actually prefer bars bent outward into the door. IMO from an engineering perspective the drift guys make the best door bar setups. They typically bend the primary door bar outward into the door about mid-door length, add a bar along the floor connecting the main hoop and front a pillar junction at the floor, then brace between the outermost point of the door bend and the floor bar. This allows the easiest access into and out of the car, most driver room, and very good side collision safety. I’ve attached a picture for reference to this design.

One problem this may bring up is passing tech. I know nasa requires bends to be within the first 6” of the door bars connecting points so you can’t do middle bends like that. I’m not sure I agree with them as I feel that design really gives the best resistance to any outside forces but tech is not the place to debate roll cage designs. You will have to specify what the cage is being used for to determine your door bar options.

If we are talking about your a-pillar plane going through your shoulder as I originally thought, you have to balance head room vertically with head room horizontally when putting a cage in. Essentially you could bring the overhead bars down some which moves them outward due to the shape of the main hoop and brings your shoulders more inward if the plane, but you now have a bar that’s beside your head. Going the other way, the more vertical clearance you gain from moving the overhead bars inward of that plane, the more your shoulder sticks out.

 

[SasaniFab]

This is the finished design, the nhra tech guy I spoke to told me to bend in the a pillar to get more clearance so that what I did, hopefully it will be ok, I also added gussets to the cage.