roll bar removability

[fordman]

i doubt grade 8 bolts would shear off. it would have to be a hollywood rollover to do that.

[aramil]

i have no idea what a grade 8 looks like, i didnt even know bolts had grades, i just call them big ones or little ones. im guessing they are pretty big and thick.

[fordman]

here is a chart that shows the marks on the head of the bolt grades. http://www.boltdepot.com/fastener-infor ... Chart.aspx

[aramil]

from the chart it should be good to go, id use them.

[ford4x4fun]

You would have to roll it off a cliff... Let it drop a hundred feet, and than I don't know if the bolts would break off!!!

[rjewkes]

I'd imagine higher than head is good as race cars with full roolcage have cage under body pannels but over head and all around.


if you got it too easy to unbolt i wouldn't trust it eihter. usualy i think the rollbar bolts/lag(screw like?) bolts just above the frame in the bed. and in a roll over could mean the diff in life and death.

I've even seen levle with the top of the bed.

i meant the cab, level with the top of the cab.

[1971ford]

thanks guys, now how do i get the bolts to go through two sections of piping alllowig it to hold the pipes together? weld on a smaller pipe that fits in the other one with a bolt going through those?

[averagef250]

You're making this way too complicated. Build a stout base off the frame with a pad, say 4"X4" that's right under the bed floor, this is real easy on a bump, the floor is perfectly flat forward of the wheelwells. Put the same flange on the base of your roll bar tubes with four bolts that bolt them together and sandwich the bed floor. Build the rollbar with a strut or angle support of some sort. Not likely on a pickup with an enclosed cab, but on open cab rigs like jeeps and broncos the rollbar can fold down and cut you in half or pin you in if it's not built right.

The tensile strength of a grade 8 bolt is far more than the load it would take to collapse your rollbar. I've seen lots of offroad trucks rolled with and without rollbars. It takes TONS of force just to crush a cab roof in, a proper rollbar is overkill for anything but the worst wrecks where you'll be dead anyway without the right gear.

There are much stronger bolts than grade 8. You want a tough bolt for chassis and cage use, not an all out strong one. Grade 8 is usually used for suspension parts because it is very strong, but will distort and stretch quite a bit before coming apart. Grade 5 will distort more, but it fails too soon for most suspension parts at the sizes that are practical.

Find the actual tensile of the steel you use for the rollbar. This is expressed as PSI. Figure the actual area in square inches of the tubing and multiply that by the tensile of the steel. Take that number and divide it by the number of bolts you plan to use and multiply it by atleast 1.5. That will give you the minimum actual tensile of the bolts you need to hold it together.

When you figure the actual tensile of the bolts you'll need to use remember that for a 1/2" bolt you do not figure the area of the cross section of the bolt as 1/2" you use the minor diameter of the bolt, for instance if you use 1/2-20 bolts the actual minor diameter of the bolt is .453 (the drill size for the same size tap is an excellent way to cheat here).

[1971ford]

It takes TONS of force just to crush a cab roof in, a proper rollbar is overkill for anything but the worst wrecks where you'll be dead anyway without the right gear.

so are you saying that a rollbar probably wouldnt be worth it because the cab would protect me in most situations? nothing extreme will be done in this truck. not even any races, just having fun at Pismo beach (a huge beach with dunes about 5 hours away from me)

thanks

[72stepside]

Just a thought here...

Of course this is your truck and you are most entitled to do what you want with it. If it was me however, with all the work you are doing with stripping it down to bare metal throughout and getting the body and engine right, I would seriously think twice about taking it off road at all. You, like me, aren't building a trailer queen, but it would sure be a shame to put yourself in a position where you have to worry if the roll bar is gonna hold or not.

Once again, your truck, do what you want. That's just my

Carry on.

[1971ford]

Thats a very good point and ive thought about it alot, and im not sure ill be making the truck a desert truck. im seeing what would have to be done and stuff. and if it was done, it would just be a beach (Pismo beach) truck. i doubt it would ever come close to rolling, but you never know when that ditch will jump in front of you
but yeah, well see once i finish the truck. it will probably be too nice and i will change my mind. im not doing anything until the truck is done.
thanks

[1971fordsdad]

AAAAAGGGGHHHHH!!!!!!!! My 14 yr old is already planning on rolling his truck!!!!!!! (this is the same reaction my dad had when I was 16 and wanted to put a roll bar in my 71 Chevelle

[RedneckTexan]

That's what my Dad said too

[1971ford]

[SoCal]

A proper safety cage connects the inside cab (which is welded, not bolted to the frame) and goes thru the rear cab and down into the frame thru the bed. Yes, thru the cab and into the frame....... anything less will be all show.