B-Pillar X brace in cage

[crazyjim]

So... I'm getting ready to do my cage in the Jeep. I'm running into a few snags though on the design process. Couple problems, I'm a big guy, 6'3" type big. So my B-Pillar bar is going to have to either be far back, or I'm going to have to bend the back bar behind the seats... if that makes sense.


Problem is this, if I move the b-pillar back, I might as well remove my rear seats. The last thing I need is rear passengers smacking their knees if they can even get in. My only other option is the run the b-pillar bar where the b-pillar actually is, then bend the bar behind the seats.

This is where I run into the X problem. I haven't been able to really think of a good way to do it. The only way I've thought of doing it in order to clear my head, doesn't seem like it's very strong. I found a picture of someone else who did it, I'd change it a bit but it's basically the same thing:

Again, I'd do mine differently, it would be an actual X but it would still be kicked out. So how viable is this as an option? A hell no?

 

[XJ_ranger]

look at Karstic's cage...

I like the Chevron bars in it...

this thread:
http://naxja.org/forum/showthread.php?t=934156&highlight=cage

 

[Mr.OverKill]

this is how i did mine

 

[crazyjim]

I like that it keeps the bars out of the rear passenger's knees, and they'll also be wearing harnesses to keep their faces out of it in a roll. I'd probably run a full bar all the way across though for the rear of the seats, but it would still have to kick out from the b-pillar.

And for more triangulation?

 

[crazyjim]

this is how i did mine

That's exactly how I was thinking about doing mine... can you still have passengers in the back seat? What kind of room do they have? Any possibility of getting some pics of someone sitting back there Troy?

 

[Mr.OverKill]

That's exactly how I was thinking about doing mine... can you still have passengers in the back seat? What kind of room do they have? Any possibility of getting some pics of someone sitting back there Troy?

i fit back there fine, but since i am single now i removed the rear seat since i wheel alone. ( no pics of people back there) the rear bars are not an issue once you are in, just a little anoying geting in. by the way, i am 6 ft tall

 

[crazyjim]

Oh sweet, perfect. I'll never sit back there, and I can't imagine anybody over 6 foot sitting in the back of my Jeep. Most of my tall friends ride up front and dawn hops in the back.

 

[Goatman]

Here's how I did mine, just as another example. I don't have an X in the B pillar because it's tied to the roof hoop and the exterior cage. The B pillar down bars are further forward than most and tie into the shoulder harness bolts, it's also pretty tight to the body.

One thing to consider is exactly how much cage do you need. The body itself provides some protection, so a cage is adding to what's already there. The cage doesn't need to do all the work by itself. I like Troy's work, but in my view the cage is way overbuilt. As an example, we've seen good rolls with exo cages with little damage to the cage, and I think we all agree that a pure exo cage doesn't have the kind of triangulation and cross bracing that we typically look for in a good cage.

I'd consider coordinating with the existing structure, thinking about less is more regarding inside body parts clearance, and thinking how much is needed to get the job done.

 

[crazyjim]

Here's how I did mine, just as another example. I don't have an X in the B pillar because it's tied to the roof hoop and the exterior cage. The B pillar down bars are further forward than most and tie into the shoulder harness bolts, it's also pretty tight to the body.

One thing to consider is exactly how much cage do you need. The body itself provides some protection, so a cage is adding to what's already there. The cage doesn't need to do all the work by itself. I like Troy's work, but in my view the cage is way overbuilt. As an example, we've seen good rolls with exo cages with little damage to the cage, and I think we all agree that a pure exo cage doesn't have the kind of triangulation and cross bracing that we typically look for in a good cage.

I'd consider coordinating with the existing structure, thinking about less is more regarding inside body parts clearance, and thinking how much is needed to get the job done.

No pictures




And as far as how good I need my cage to be... I think I need more cage than most rock crawlers... if I roll it won't be at 5 mph... it's going to be upwards of 70mph probably multiple times. Realistically hopefully if I ever do roll, I'll be able to get slowed down enough to make it a 40-50mph roll instead, but I still don't want to risk it. Me and my GF are precious cargo.

 

[Goatman]

Oops! :looney:

We've seen some pretty good rolls in XJ's at speed, with no roll cage, and they don't do too bad. My son-in-law rolled at 50 mph and didn't have a scratch, and I've seen others. Make it strong, but consider it a part of the overall structure, not strong enough to do all the work by itself, and I think you'll end up with a more functional cage.

 

[Jump This]

Having seen Jim drive (as well as Richard) I'd suggest building it as strong as you can. I know that many have used a single cross brace behind the seat, diagonal from the top of the drivers side to the bottom passenger side.
But you still need a place to mount your shoulder harness. That normally requires a spanner bar.
I'm not sure how Richard mounts his belts in the Yellow Jeep, but without a cross brace you may run into the problem of finding a proper location for your shoulder harness *(it should never be more than two inches below your shoulders.)

As far as Karstic's cage goes....it would probably be fine if the welds on it were any good!

 

[Goatman]

I don't have harnesses (I should). I think one cross bar for the harnesses and one diagonal bar, and have the B pillar tie into the shoulder belt bolts, and that would be plenty strong as far as the B pillar is concerned. On mine, the down bars are forward to keep tight to the existing pillar, then the top is angled back to give head room. But, I also have the exterior roof halo.

 

[AZXJ]

Here's mine

 

[Jump This]

Damn Zonies...
did we really need six pictures to show your cross brace?

 

[AZXJ]

Why yes, Yes you did..

 

[crazyjim]

Not to mention it's a 2 door and doesn't help me at all

 

[AZXJ]

That was the point..

 

[The Griz]

So... I'm getting ready to do my cage in the Jeep. I'm running into a few snags though on the design process. Couple problems, I'm a big guy, 6'3" type big. So my B-Pillar bar is going to have to either be far back, or I'm going to have to bend the back bar behind the seats... if that makes sense.


Problem is this, if I move the b-pillar back, I might as well remove my rear seats. The last thing I need is rear passengers smacking their knees if they can even get in. My only other option is the run the b-pillar bar where the b-pillar actually is, then bend the bar behind the seats.

This is where I run into the X problem. I haven't been able to really think of a good way to do it. The only way I've thought of doing it in order to clear my head, doesn't seem like it's very strong. I found a picture of someone else who did it, I'd change it a bit but it's basically the same thing:

Again, I'd do mine differently, it would be an actual X but it would still be kicked out. So how viable is this as an option? A hell no?

i have riddin in the back of this jeep on a trail and it was kinda comfortable the only problem was getting in and out we also had 4 adults and 2 dogs in the vehicle.

 

[crazyjim]

i have riddin in the back of this jeep on a trail and it was kinda comfortable the only problem was getting in and out we also had 4 adults and 2 dogs in the vehicle.

Hmmmm, good to know. So then there's more room back there than I thought I guess?