Roll bar thru the cab questions

[ChampTrucking]

On the gasser truck we are building it has been determined we want to run rear down tubes from the main hoop. This will require running them thru the cab sheet metal or thru the back window. The cab is a 5 window and the rear window is narrower than the spread of the frame rails. To keep everything in line it will have to run thru the sheet metal. So my question is does anyone know of a rubber grommet that can be used to weather proof the pass thru? We tossed around welding and finishing it but any frame flex will just ruin the paint and body work. So any ideas or prior examples??? Thanks for the help!! Rich

[DanStokes]

There's always the slit hose trick. Cut a length of fuel (or similar) hose to the approximate length of the OD of the hole, slit it down the outside (hose usually has a curl from the reel), and slide it over the sheet metal. It'll take some maneuvering to get it in place but it works. I usually use 3/8" hose for a hole with a decent sized OD like this will be, and I put the gap at the bottom.

Another thought would be a fuel filler gasket like for an old truck (where the fill tube goes thru the body) but I think the center hole would be too big.

Dan

[Ron Ward]

How about a modified shifter boot or CV shaft boot?

Just throwing ideas out...


Ron

[Ron Ward]

Can you show a pic of the area on the cab where you expect the bars to come through? I have a few ideas (google flexible water tight grommets) but need to know if the cab sheetmetal will be flat or if it will be on a curved surface.


Ron

[ChampTrucking]

Some good ideas. I think it will be curved Ron,but that remains to be seen. He has to choose what seat combo first,then plan the cage other than the main hoop that is. This ought to be fun....

[JOES66FURY]

there is a large grommet that fits between the filler tube and the tank on my plymouth that I bet would work really well in this application.

see if this link works and this will give you an idea of what I am talking about..

http://www.google.com/#hl=en&tbo=d&site=&source=hp&q=plymouth+fuel+filler+neck+grommet&oq=plymouth+fuel+filler+neck+grommet&gs_l=hp.3...0.0.1.5366.0.0.0.0.0.0.0.0..0.0.les%3B..0.0...1c.lireYAQEjBQ&fp=1&biw=1440&bih=705&bav=on.2,or.r_gc.r_pw.&cad=b

[Chassisman]

I've done this a lot.....I'll see if I can find some pics.....easiest and coolest way is inner tube and some 1/8 aluminum plate....I basically make a double sided shifter boot...I use 8-32 counter sunk stainless hardware to clamp it down.....I use rubber on the inside and outside for a double seal. Instead of inner tube I use industrial rubber sheet....I get it from CIR out here but truck tube works just as well....

[JOES66FURY]

I've done this a lot.....I'll see if I can find some pics.....easiest and coolest way is inner tube and some 1/8 aluminum plate....I basically make a double sided shifter boot...I use 8-32 counter sunk stainless hardware to clamp it down.....I use rubber on the inside and outside for a double seal. Instead of inner tube I use industrial rubber sheet....I get it from CIR out here but truck tube works just as well....

clever, almost like an aircraft vibration isolater....

[dieselgeek]

I've done this a lot.....I'll see if I can find some pics.....easiest and coolest way is inner tube and some 1/8 aluminum plate....I basically make a double sided shifter boot...I use 8-32 counter sunk stainless hardware to clamp it down.....I use rubber on the inside and outside for a double seal. Instead of inner tube I use industrial rubber sheet....I get it from CIR out here but truck tube works just as well....

This is the RIGHT way to do it. If you just do a grommet, it's only going to wear out quick. You will be surprised how much movement between the cab and bar you're going to get. We fought this on Parish's truck at Drag Week. Definitely do what Chassisman is recommending, it'll not only weatherproof but it'll last. Grommets will fail completely.

[Russell]

How much gap do you need to keep it from binding?

[DanStokes]

I think I'll try Chassismans method on the S-10. They go thru the back window and it would be nice to seal it up.

Dan

[BluLightning]

This is how the Lightning guys do it. This is what will probably be in my truck eventually.

http://www.rhodescustomauto.com/ericeldreth.htm

[Chassisman]

This is how the Lightning guys do it. This is what will probably be in my truck eventually.

http://www.rhodescustomauto.com/ericeldreth.htm

Thats pretty much exactly how I've been doing them since 1992......his bar set up is nice.....but I'd land the side bar on a 3x2 outrigger....little more surface area contacting the frame....on a hard roll that curve could collapse and the main hoop could fold over.....not likely but if it did it would be ugly...

[BluLightning]

Thats pretty much exactly how I've been doing them since 1992......his bar set up is nice.....but I'd land the side bar on a 3x2 outrigger....little more surface area contacting the frame....on a hard roll that curve could collapse and the main hoop could fold over.....not likely but if it did it would be ugly...

Good to know for when I get that far.

[Deaf Bob]

Pretty much geometry.. How angles and curves react with force upon a spot..
To play and test your theory, gas weld coat hangers in your roll cage configuration, then mimic the roll or crash forces..
It will bend easy.. If it doesn't.. Then you have a strong cage.. But the point is it bends easy enough to observe what happens thus you can figure if your set-up will work..