Stock roll bar (sport bar) strength - 1983 CJ7
 

I'm looking to get a full roll cage installed in my 83 CJ7 - ideally as
an "add-on" to the existing very sound, very solid stock factory roll
bar (sport bar).

The tub is also very sound - not rusted at all where the stock bar
attaches to the tub behnd the seats and on the wheelhouses

For strength reasons I want to go with DOM tubing for the additional
cage portions - rather than using the cheaper - but weaker - HREW
(welded) tubing.

One of the shops I talked with said the factory bar was so weak that he
wouldn't recommend additng a cage (front & rear) to the stock bar using
DOM, but would do the addition using the HREW tubing.

Opinions about using the factory bar as a part of a full cage made of
DOM tubing???

BTW - He said he'd be happy to use DOM for a full, custom cage - not
using any of the stock bar - but at a considrably higher price.

Yes - I know I shouldn't pinch pennies too much when talking safety
stuff - but .....

Thanks

Re: Stock roll bar (sport bar) strength - 1983 CJ7
 

Sounds to me he's like just covering his a** in the litigious
world. I would let him build the whole thing and sell your imitation
roll bar to someone that has flopped theirs on it's side.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/

"lynnhowlyn@aol.com" wrote:
>
> I'm looking to get a full roll cage installed in my 83 CJ7 - ideally as
> an "add-on" to the existing very sound, very solid stock factory roll
> bar (sport bar).
>
> The tub is also very sound - not rusted at all where the stock bar
> attaches to the tub behnd the seats and on the wheelhouses
>
> For strength reasons I want to go with DOM tubing for the additional
> cage portions - rather than using the cheaper - but weaker - HREW
> (welded) tubing.
>
> One of the shops I talked with said the factory bar was so weak that he
> wouldn't recommend additng a cage (front & rear) to the stock bar using
> DOM, but would do the addition using the HREW tubing.
>
> Opinions about using the factory bar as a part of a full cage made of
> DOM tubing???
>
> BTW - He said he'd be happy to use DOM for a full, custom cage - not
> using any of the stock bar - but at a considrably higher price.
>
> Yes - I know I shouldn't pinch pennies too much when talking safety
> stuff - but .....
>
> Thanks

Re: Stock roll bar (sport bar) strength - 1983 CJ7
 

Sounds to me he's like just covering his a** in the litigious
world. I would let him build the whole thing and sell your imitation
roll bar to someone that has flopped theirs on it's side.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/

"lynnhowlyn@aol.com" wrote:
>
> I'm looking to get a full roll cage installed in my 83 CJ7 - ideally as
> an "add-on" to the existing very sound, very solid stock factory roll
> bar (sport bar).
>
> The tub is also very sound - not rusted at all where the stock bar
> attaches to the tub behnd the seats and on the wheelhouses
>
> For strength reasons I want to go with DOM tubing for the additional
> cage portions - rather than using the cheaper - but weaker - HREW
> (welded) tubing.
>
> One of the shops I talked with said the factory bar was so weak that he
> wouldn't recommend additng a cage (front & rear) to the stock bar using
> DOM, but would do the addition using the HREW tubing.
>
> Opinions about using the factory bar as a part of a full cage made of
> DOM tubing???
>
> BTW - He said he'd be happy to use DOM for a full, custom cage - not
> using any of the stock bar - but at a considrably higher price.
>
> Yes - I know I shouldn't pinch pennies too much when talking safety
> stuff - but .....
>
> Thanks

Re: Stock roll bar (sport bar) strength - 1983 CJ7
 

Sounds to me he's like just covering his a** in the litigious
world. I would let him build the whole thing and sell your imitation
roll bar to someone that has flopped theirs on it's side.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/

"lynnhowlyn@aol.com" wrote:
>
> I'm looking to get a full roll cage installed in my 83 CJ7 - ideally as
> an "add-on" to the existing very sound, very solid stock factory roll
> bar (sport bar).
>
> The tub is also very sound - not rusted at all where the stock bar
> attaches to the tub behnd the seats and on the wheelhouses
>
> For strength reasons I want to go with DOM tubing for the additional
> cage portions - rather than using the cheaper - but weaker - HREW
> (welded) tubing.
>
> One of the shops I talked with said the factory bar was so weak that he
> wouldn't recommend additng a cage (front & rear) to the stock bar using
> DOM, but would do the addition using the HREW tubing.
>
> Opinions about using the factory bar as a part of a full cage made of
> DOM tubing???
>
> BTW - He said he'd be happy to use DOM for a full, custom cage - not
> using any of the stock bar - but at a considrably higher price.
>
> Yes - I know I shouldn't pinch pennies too much when talking safety
> stuff - but .....
>
> Thanks

Re: Stock roll bar (sport bar) strength - 1983 CJ7
 

DOM tube is drawn from HREW, the drawing work hardens the tube,
increases the yield (bending strength) by around 30%. You have to use
the strength of materials tables to get the exact numbers but usually
you can get close and substitute one diameter bigger HREW for DOM (same
wall) or same diameter and one wall thickness bigger.

If you REALLY need a full cage (tough enough for rolling down the
mountainside), I'm much more concerned about the mounts and especially
the mounting of the cage to the body tub. The factory mounts are way too
small to transfer the load to the tub in a seious roll.

So all the BS at the shop comes down to what strength tube to use, DOM
will be slightly lighter for the same strength. If you have a good
fabrication shop, he won't use DOM, have him use the HREW one size larger.

The other argument you will hear is that "HREW will split at the seam"
I'll conceed that DOM is a premium material, much more uniform than
HREW. But good quality HREW tube made in a modern tube mill just doesn't
have the splitting problem.



lynnhowlyn@aol.com wrote:
> I'm looking to get a full roll cage installed in my 83 CJ7 - ideally as
> an "add-on" to the existing very sound, very solid stock factory roll
> bar (sport bar).
>
> The tub is also very sound - not rusted at all where the stock bar
> attaches to the tub behnd the seats and on the wheelhouses
>
> For strength reasons I want to go with DOM tubing for the additional
> cage portions - rather than using the cheaper - but weaker - HREW
> (welded) tubing.
>
> One of the shops I talked with said the factory bar was so weak that he
> wouldn't recommend additng a cage (front & rear) to the stock bar using
> DOM, but would do the addition using the HREW tubing.
>
> Opinions about using the factory bar as a part of a full cage made of
> DOM tubing???
>
> BTW - He said he'd be happy to use DOM for a full, custom cage - not
> using any of the stock bar - but at a considrably higher price.
>
> Yes - I know I shouldn't pinch pennies too much when talking safety
> stuff - but .....
>
> Thanks
>

Re: Stock roll bar (sport bar) strength - 1983 CJ7
 

DOM tube is drawn from HREW, the drawing work hardens the tube,
increases the yield (bending strength) by around 30%. You have to use
the strength of materials tables to get the exact numbers but usually
you can get close and substitute one diameter bigger HREW for DOM (same
wall) or same diameter and one wall thickness bigger.

If you REALLY need a full cage (tough enough for rolling down the
mountainside), I'm much more concerned about the mounts and especially
the mounting of the cage to the body tub. The factory mounts are way too
small to transfer the load to the tub in a seious roll.

So all the BS at the shop comes down to what strength tube to use, DOM
will be slightly lighter for the same strength. If you have a good
fabrication shop, he won't use DOM, have him use the HREW one size larger.

The other argument you will hear is that "HREW will split at the seam"
I'll conceed that DOM is a premium material, much more uniform than
HREW. But good quality HREW tube made in a modern tube mill just doesn't
have the splitting problem.



lynnhowlyn@aol.com wrote:
> I'm looking to get a full roll cage installed in my 83 CJ7 - ideally as
> an "add-on" to the existing very sound, very solid stock factory roll
> bar (sport bar).
>
> The tub is also very sound - not rusted at all where the stock bar
> attaches to the tub behnd the seats and on the wheelhouses
>
> For strength reasons I want to go with DOM tubing for the additional
> cage portions - rather than using the cheaper - but weaker - HREW
> (welded) tubing.
>
> One of the shops I talked with said the factory bar was so weak that he
> wouldn't recommend additng a cage (front & rear) to the stock bar using
> DOM, but would do the addition using the HREW tubing.
>
> Opinions about using the factory bar as a part of a full cage made of
> DOM tubing???
>
> BTW - He said he'd be happy to use DOM for a full, custom cage - not
> using any of the stock bar - but at a considrably higher price.
>
> Yes - I know I shouldn't pinch pennies too much when talking safety
> stuff - but .....
>
> Thanks
>

Re: Stock roll bar (sport bar) strength - 1983 CJ7
 

DOM tube is drawn from HREW, the drawing work hardens the tube,
increases the yield (bending strength) by around 30%. You have to use
the strength of materials tables to get the exact numbers but usually
you can get close and substitute one diameter bigger HREW for DOM (same
wall) or same diameter and one wall thickness bigger.

If you REALLY need a full cage (tough enough for rolling down the
mountainside), I'm much more concerned about the mounts and especially
the mounting of the cage to the body tub. The factory mounts are way too
small to transfer the load to the tub in a seious roll.

So all the BS at the shop comes down to what strength tube to use, DOM
will be slightly lighter for the same strength. If you have a good
fabrication shop, he won't use DOM, have him use the HREW one size larger.

The other argument you will hear is that "HREW will split at the seam"
I'll conceed that DOM is a premium material, much more uniform than
HREW. But good quality HREW tube made in a modern tube mill just doesn't
have the splitting problem.



lynnhowlyn@aol.com wrote:
> I'm looking to get a full roll cage installed in my 83 CJ7 - ideally as
> an "add-on" to the existing very sound, very solid stock factory roll
> bar (sport bar).
>
> The tub is also very sound - not rusted at all where the stock bar
> attaches to the tub behnd the seats and on the wheelhouses
>
> For strength reasons I want to go with DOM tubing for the additional
> cage portions - rather than using the cheaper - but weaker - HREW
> (welded) tubing.
>
> One of the shops I talked with said the factory bar was so weak that he
> wouldn't recommend additng a cage (front & rear) to the stock bar using
> DOM, but would do the addition using the HREW tubing.
>
> Opinions about using the factory bar as a part of a full cage made of
> DOM tubing???
>
> BTW - He said he'd be happy to use DOM for a full, custom cage - not
> using any of the stock bar - but at a considrably higher price.
>
> Yes - I know I shouldn't pinch pennies too much when talking safety
> stuff - but .....
>
> Thanks
>

Re: Stock roll bar (sport bar) strength - 1983 CJ7
 

RoyJ wrote:
> DOM tube is drawn from HREW, the drawing work hardens the tube,
> increases the yield (bending strength) by around 30%. You have to use
> the strength of materials tables to get the exact numbers but usually
> you can get close and substitute one diameter bigger HREW for DOM (same
> wall) or same diameter and one wall thickness bigger.
>
> If you REALLY need a full cage (tough enough for rolling down the
> mountainside), I'm much more concerned about the mounts and especially
> the mounting of the cage to the body tub. The factory mounts are way too
> small to transfer the load to the tub in a seious roll.
>
> So all the BS at the shop comes down to what strength tube to use, DOM
> will be slightly lighter for the same strength. If you have a good
> fabrication shop, he won't use DOM, have him use the HREW one size larger.
>
> The other argument you will hear is that "HREW will split at the seam"
> I'll conceed that DOM is a premium material, much more uniform than
> HREW. But good quality HREW tube made in a modern tube mill just doesn't
> have the splitting problem.
>
>
>
> lynnhowlyn@aol.com wrote:
> > I'm looking to get a full roll cage installed in my 83 CJ7 - ideally as
> > an "add-on" to the existing very sound, very solid stock factory roll
> > bar (sport bar).
> >
> > The tub is also very sound - not rusted at all where the stock bar
> > attaches to the tub behnd the seats and on the wheelhouses
> >
> > For strength reasons I want to go with DOM tubing for the additional
> > cage portions - rather than using the cheaper - but weaker - HREW
> > (welded) tubing.
> >
> > One of the shops I talked with said the factory bar was so weak that he
> > wouldn't recommend additng a cage (front & rear) to the stock bar using
> > DOM, but would do the addition using the HREW tubing.
> >
> > Opinions about using the factory bar as a part of a full cage made of
> > DOM tubing???
> >
> > BTW - He said he'd be happy to use DOM for a full, custom cage - not
> > using any of the stock bar - but at a considrably higher price.
> >
> > Yes - I know I shouldn't pinch pennies too much when talking safety
> > stuff - but .....
> >
> > Thanks
> >

I had a CJ with the stock bar in the back and an add on "full cage" in
the front. I rolled down a hill one day (about 1 and a half times) and
it held up fine. Granted this was at a very slow speed.

Re: Stock roll bar (sport bar) strength - 1983 CJ7
 

RoyJ wrote:
> DOM tube is drawn from HREW, the drawing work hardens the tube,
> increases the yield (bending strength) by around 30%. You have to use
> the strength of materials tables to get the exact numbers but usually
> you can get close and substitute one diameter bigger HREW for DOM (same
> wall) or same diameter and one wall thickness bigger.
>
> If you REALLY need a full cage (tough enough for rolling down the
> mountainside), I'm much more concerned about the mounts and especially
> the mounting of the cage to the body tub. The factory mounts are way too
> small to transfer the load to the tub in a seious roll.
>
> So all the BS at the shop comes down to what strength tube to use, DOM
> will be slightly lighter for the same strength. If you have a good
> fabrication shop, he won't use DOM, have him use the HREW one size larger.
>
> The other argument you will hear is that "HREW will split at the seam"
> I'll conceed that DOM is a premium material, much more uniform than
> HREW. But good quality HREW tube made in a modern tube mill just doesn't
> have the splitting problem.
>
>
>
> lynnhowlyn@aol.com wrote:
> > I'm looking to get a full roll cage installed in my 83 CJ7 - ideally as
> > an "add-on" to the existing very sound, very solid stock factory roll
> > bar (sport bar).
> >
> > The tub is also very sound - not rusted at all where the stock bar
> > attaches to the tub behnd the seats and on the wheelhouses
> >
> > For strength reasons I want to go with DOM tubing for the additional
> > cage portions - rather than using the cheaper - but weaker - HREW
> > (welded) tubing.
> >
> > One of the shops I talked with said the factory bar was so weak that he
> > wouldn't recommend additng a cage (front & rear) to the stock bar using
> > DOM, but would do the addition using the HREW tubing.
> >
> > Opinions about using the factory bar as a part of a full cage made of
> > DOM tubing???
> >
> > BTW - He said he'd be happy to use DOM for a full, custom cage - not
> > using any of the stock bar - but at a considrably higher price.
> >
> > Yes - I know I shouldn't pinch pennies too much when talking safety
> > stuff - but .....
> >
> > Thanks
> >

I had a CJ with the stock bar in the back and an add on "full cage" in
the front. I rolled down a hill one day (about 1 and a half times) and
it held up fine. Granted this was at a very slow speed.

Re: Stock roll bar (sport bar) strength - 1983 CJ7
 

RoyJ wrote:
> DOM tube is drawn from HREW, the drawing work hardens the tube,
> increases the yield (bending strength) by around 30%. You have to use
> the strength of materials tables to get the exact numbers but usually
> you can get close and substitute one diameter bigger HREW for DOM (same
> wall) or same diameter and one wall thickness bigger.
>
> If you REALLY need a full cage (tough enough for rolling down the
> mountainside), I'm much more concerned about the mounts and especially
> the mounting of the cage to the body tub. The factory mounts are way too
> small to transfer the load to the tub in a seious roll.
>
> So all the BS at the shop comes down to what strength tube to use, DOM
> will be slightly lighter for the same strength. If you have a good
> fabrication shop, he won't use DOM, have him use the HREW one size larger.
>
> The other argument you will hear is that "HREW will split at the seam"
> I'll conceed that DOM is a premium material, much more uniform than
> HREW. But good quality HREW tube made in a modern tube mill just doesn't
> have the splitting problem.
>
>
>
> lynnhowlyn@aol.com wrote:
> > I'm looking to get a full roll cage installed in my 83 CJ7 - ideally as
> > an "add-on" to the existing very sound, very solid stock factory roll
> > bar (sport bar).
> >
> > The tub is also very sound - not rusted at all where the stock bar
> > attaches to the tub behnd the seats and on the wheelhouses
> >
> > For strength reasons I want to go with DOM tubing for the additional
> > cage portions - rather than using the cheaper - but weaker - HREW
> > (welded) tubing.
> >
> > One of the shops I talked with said the factory bar was so weak that he
> > wouldn't recommend additng a cage (front & rear) to the stock bar using
> > DOM, but would do the addition using the HREW tubing.
> >
> > Opinions about using the factory bar as a part of a full cage made of
> > DOM tubing???
> >
> > BTW - He said he'd be happy to use DOM for a full, custom cage - not
> > using any of the stock bar - but at a considrably higher price.
> >
> > Yes - I know I shouldn't pinch pennies too much when talking safety
> > stuff - but .....
> >
> > Thanks
> >

I had a CJ with the stock bar in the back and an add on "full cage" in
the front. I rolled down a hill one day (about 1 and a half times) and
it held up fine. Granted this was at a very slow speed.