Building Rollbar

[Bino]

Hey all,
I've got a '71 K5, and with summer upon us... the top needs to come off, and a rollbar needs to go in. I'd like to build it to the same specs as one of the dealer installed units. Would somebody mind providing me with some basic dimensions on one of these bad boys... overall width across the bottom, hole spacing on bolt-down plates, tube diameter, height at which rear down tube attaches to main hoop, distance up fender well (from floor) where down tube plate mounts to fender well... etc.

Also, anybody know of a 3.42 gearset for a Dana 44? I found one company but they discontinued them. Otherwise... I'm dropping off a 10-bolt for a full rebuild tomorrow afternoon.

Much Thanks

[Yukon Jack]

Welcome to the board. Here are some pics of my 70 K5's roll bar but I can't tell you if it would have been a dealer installed or aftermarket piece.

[jhow66]

Something like these-bolts to floor and wheel tub-3"

[Bino]

Thanks for the quick reply with the dimensions. I now find myself a bit torn. I was thinking of doing a roll bar like you've got Yukon Jack, but I think it might be inconvenient for the rear passengers. I had planned on doing a bar like Green Monster and VTBlazer have on their vehicles (the topless thread is very useful when trying to nail down which roll bar is preferred). Would somebody mind posting some dimensions for that other bar as well?

jhow66, thanks for posting those pics, but I'm looking for a weld in style rather than a bolt-in.

Thanks

[Yukon Jack]

I don't think the rear bar causes any problems for rear passengers. My daughter did pump her head once getting to the rear but not sure that the top bar could be put anywhere else.

[Mike C]

Yukon Jack's is the SMittybuilt bar. I had the Smittybuilt bar/cage conversion in my Jimmy, but the front part won't clear my STC top. Am going to build my own now that the soft top is installed. The bar itself fits no prob, it was the front legs that were too high for soft top.

[vtblazer]

Originally Posted by Bino

Hey all,
I've got a '71 K5, and with summer upon us... the top needs to come off, and a rollbar needs to go in. I'd like to build it to the same specs as one of the dealer installed units. Would somebody mind providing me with some basic dimensions on one of these bad boys... overall width across the bottom, hole spacing on bolt-down plates, tube diameter, height at which rear down tube attaches to main hoop, distance up fender well (from floor) where down tube plate mounts to fender well... etc.

Also, anybody know of a 3.42 gearset for a Dana 44? I found one company but they discontinued them. Otherwise... I'm dropping off a 10-bolt for a full rebuild tomorrow afternoon.

Much Thanks

Welcome to the board.

The bar set up your hoping to recreate as a safety feature in your own blazer is 'NOT' a roll bar, your better off designing something that suites your own particular needs to 'BE' an actual roll bar.

Glad to see your wanting to do this, it's a good idea for sure.

[Bino]

Yes, that is a very good point. Thank you for clearing up my terminology. I figured "roll bar" most clearly conveyed the device I was looking into... even though it is a bit of a misnomer.

So, do you think that the style of "roll bar" that Yukon Jack is running would offer better roll over protection than the one that is on your blazer vtblazer? The mounting points on yours are pretty close, which could cause it to fold to the rear or front during a roll over. Obviously the only "good" roll bar would attach directly to the frame... I'm still on the fence about that one. While I do not plan on wheeling this vehicle hard, nor do I drive like a maniac, I would still like some form of roll over protection in the very unlikely even that it's necessary. I also need a place to mount 3 point seat belts...

Thanks

[Yukon Jack]

I doubt my style would do much in the way of protection in a roll over. This style just bolts to the floor and I could see it punching through the floor in a hard roll. Sure it's better than nothing but I too wouldn't consider it a functional roll bar.

I would think it would be unwise to attach shoulder belts to this style "roll bar". If you rolled and the "roll bar" pushed through the floor, you're going down with the bar!

[red71cheyenne]

Just for my own info, as mine is a bolt in affair as well, where would a "real" roll bar mount? I've seen the one that VT has in his, looks like it kind of rides along the floor and also mounts to the frame. Do they need to mount to the frame in order to really protect you? Thanks, Jeff.

[FormerMember]

Originally Posted by red71cheyenne

Just for my own info, as mine is a bolt in affair as well, where would a "real" roll bar mount? I've seen the one that VT has in his, looks like it kind of rides along the floor and also mounts to the frame. Do they need to mount to the frame in order to really protect you? Thanks, Jeff.

When building a roll cage, there are two schools of thought. Attach to the frame and hope everything stays in one piece (frame, body and cage) or build the cage to protect the occupants (completely) and break away from the chassis.

I built Kurt's cage (in the blue blazer) with a bit of help and it's tied into the frame in 6 locations, which also strengthens the frame itself. We determined that it would take a heck of allot to detach the chassis from the cage and it would make a far more stable platform. Most tend to connect to the frame, as it's very tough to model a break away cage pod.

[vtblazer]

Originally Posted by grendel

I built Kurt's cage (in the blue blazer) with a bit of help and it's tied into the frame in 6 locations, which also strengthens the frame itself. We determined that it would take a heck of allot to detach the chassis from the cage and it would make a far more stable platform. Most tend to connect to the frame, as it's very tough to model a break away cage pod.

Jon, I think he's refering to the green blazer bar. (I think)
Don't know if he's seen your full cage handy work in the blue one.

[FormerMember]

Originally Posted by vtblazer

Jon, I think he's refering to the green blazer bar. (I think)
Don't know if he's seen your full cage handy work in the blue one.

Whoops... They call those "sport bars". I've also heard those called "light bars" as well.

[Bino]

Originally Posted by vtblazer

Jon, I think he's refering to the green blazer bar. (I think)
Don't know if he's seen your full cage handy work in the blue one.

Yes... that is a bit farther than I was thinking of going. The green Blazer is what I was making reference to. So "Sport Bar" it shall be... not like lights would fit under the top anyway...

You've got me thinking that I'll make some sort of hybrid bar. Probably a basic 4 point "sport bar" with frame tie-ins. This should really be all the protection I need, plus shoulder belt mounts. I'm guessing that about 2" OD with .120 wall tubing is pretty standard?