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Cage Tie-ins Why do they do this? what is the point?

Rusted

Rusted

Let's Ride!
Supporting Member
Location
Sandy
When looking for cage tie-ins I see lots of this type of thing. Why do they do this??? They are easy, they can be unbolted, maybe some vibration dappening, sure I get that. But how can they be safe? If you go upside down what is stopping that from rotating just like a leaf spring shackle and letting your cage sink or move? These are the joints that are used in a suspension system because they are meant to move, in a safe cage design why would you ever want them to move?




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J

jswainthug

Well-Known Member
Location
Murray
With out those in a roll over the cage plates mounted to the body can actually tear through. The tie ins make it so your cage sits on a solid surface. Its all for safety and a must for serious rigs IMO.
 
Z

Zombie

Random Dead Guy
Location
Sandy Utah
Body bushings allow movement between the body and frame. If your cage is completely solid, it would destroy the body metal around the cage plates.
 
TJDukit

TJDukit

I.Y.A.A.Y.A.S.
Location
Clearfield
Zombie said:
Body bushings allow movement between the body and frame. If your cage is completely solid, it would destroy the body metal around the cage plates.
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X2 on that unless you just cut holes through the body you have to have some bushings to prevent the body from tearing. And those bushing won't rotate as long as the cage is all tied together the way it should be.
 
lewis

lewis

Fight Till You Die
Location
Hairyman
Having rolled a few times with a cage that was tied in solid to the frame, I would be a little hesitant to use these since the solid mounted cage flexed 4-6 inches in the rollover. With these installed it allows even more movement.
 
S

STAG

Well-Known Member
Cage-frame tie-ins tranfer the energy of a roll, directly to the frame; as the body alone is NOT strong enough to support a multi-roll accident. Also, they help prevent latteral "sheer" of the cage mounting plates & bolts.

A good cage-frame tie-in kit will have the upper mount plate (inside the body) slightly smaller than the lower mount plate (bottom side of body.) This is to prevent sheer also. Think of it this way, if the mounting plates are the same size, then the edges of the plates will put stress on one, localized area, and it will "tear" the body right in two, granted the added fact of a frame-tie in does greatly reduce this, however it can still happen with one if the plates are the same size.

*IMHO* IF YOU HAVE A 2" or 3" BODY LIFT- THESE ARE AN ABSOLUTE MUST! .... If you get in an auto accident with a body lift, especially the larger ones, it is putting tons of torque on your body-mount bolts... (when your frame stops suddenly, the vehicle's body still wants to keep moving forward (newtons law haha) and can easily cause damage to the body mount locations; this includes breaking the bolts, cracking the rubber/polyurethane, or even ripping the mounting plates right off of the body.

-Even with that said, I do reccomend that all cages should have a tie-in kit...

Not to mention the fact that they will greatly reduce frame flexing while offroading, which can cause damage again to body mount systems, and the body itself.

The bushings are just to help absorb some of the shock in the event of a rollover, and to help keep the body and cage free of squeaks when hitting bumps etc...
 
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cruiseroutfit

cruiseroutfit

Cruizah!
Moderator
Vendor
Location
Sandy, Ut
There are several theories to roll-cage design and fab imo. One is you try and tie your cage into the frame, preventing the chassis and cage from massively separating. This leaves your seats and belts tied to the chassis or cage, or a combination of both. The other thought is to build your cage with an integral seat cradle, the cradle being part of the roll cage but not necessarily tied to the frame. Even if the cage were to separate from the sheet metal, you would still be protected by the cage. Much like the "excape pod" built into many motorsports designs. They design everything else to seperate from the cockpit which is built to protect the occupant, not stay attached to the mass of wreckage. I think with sound engineering and fab practices either can be absolutely done cleanly and successfully.
 
S

STAG

Well-Known Member
Cherokeester said:
The poly kit that is $33.00 is not complete. If you want the poly complete kit you will pay $150.00.
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Whats not complete about it? Bolts? The tube that runs from the bushing to the plate? If you built your own cage you should have extra DOM running around...

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UNSTUCK

UNSTUCK

But stuck more often.
Chocflip201 said:
A good cage-frame tie-in kit will have the upper mount plate (inside the body) slightly smaller than the lower mount plate (bottom side of body.) This is to prevent sheer also. Think of it this way, if the mounting plates are the same size, then the edges of the plates will put stress on one, localized area, and it will "tear" the body right in two, granted the added fact of a frame-tie in does greatly reduce this, however it can still happen with one if the plates are the same size.
Click to expand...

I have heard this a few times, but haven't heard it put well enough to start practicing it. The way I see it, if you have the same size plates above and below the body, the stress is on the edges of those plates. Now if you have two different size plates, the larger plage is going to put presure on the smaller plate right at the edges (well, and across the plate as well). So the same problem remains. The only way it might be better would be that it is now harder for the cage to pull through the body in one direction then the other direction.

However, none of this even matters if the cage is tied to the frame, well I guess if you hit the body hard enough in the roll, the body could still move sideways and shear, but then the size and shape of the plates wouldn't matter anyways.

So now it comes down to ride quality. The flex allowed by the bushing will give the rig a much nicer ride, at the cost an X amount of safety. With the cage tied directly to the frame, there is almost no flex, and an X amount safer, at the cost of ride comfort. I have had no problems with body parts ripping due to flex, so I can't say either way.

So I recomend a rig that spends most the time on roads with the intent of never rolling to be built with bushings. I then recomend a "trail" rig to be tied directly to the frame. And even using a sleave between the cage mounting plates when it can be done, which pretty much guarentees no shear.
 
Cherokeester

Cherokeester

Registered User
Location
Wellsville Utah
small poly kit $33.00


regular poly kit $150.00


genright kit $99.00
 

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S

STAG

Well-Known Member
UNSTUCK said:
I have heard this a few times, but haven't heard it put well enough to start practicing it. The way I see it, if you have the same size plates above and below the body, the stress is on the edges of those plates. Now if you have two different size plates, the larger plage is going to put presure on the smaller plate right at the edges (well, and across the plate as well). So the same problem remains. The only way it might be better would be that it is now harder for the cage to pull through the body in one direction then the other direction.
Click to expand...

Yeah thats why most companies put the smaller plate on top, so that in the event of a roof rollover the pressure gets put directly onto a larger plate, and doesn't push on any edges.

UNSTUCK said:
However, none of this even matters if the cage is tied to the frame, well I guess if you hit the body hard enough in the roll, the body could still move sideways and shear, but then the size and shape of the plates wouldn't matter anyways.
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Yeah but the sideways shear would be worse if there was no cage tie in at all.. Agree?
 
S

STAG

Well-Known Member
Cherokeester said:
small poly kit $33.00


regular poly kit $150.00


genright kit $99.00
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(So if the "regular" poly kit is the attachment on the lower right)


"Small" Poly kit- 1 bushing + 2 plates =$33

"Regular" Poly kit- 2 bushings, 4 plates, 2 DOM tubes, + bolts =$150...


So if I bought 2 small poly kits, and bolts, and used extra DOM from my cage, I am still a whole lot cheaper than the gen-right kit, and a TON cheaper than buying the regular poly kit... thats just what I'd do.. .just giving my opinion... but I guess the options are out there for anyone to decide what they want to do..
 
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cheepin

cheepin

Active Member
Location
Parachute Co.
UNSTUCK said:
I have heard this a few times, but haven't heard it put well enough to start practicing it. The way I see it, if you have the same size plates above and below the body, the stress is on the edges of those plates. Now if you have two different size plates, the larger plage is going to put presure on the smaller plate right at the edges (well, and across the plate as well). So the same problem remains. The only way it might be better would be that it is now harder for the cage to pull through the body in one direction then the other direction.
Click to expand...

Think of how a metal stomp stomp shear works.2 pieces of steel that are tight together and pressed passed each other shear or cut the metal and the passing point.
Or for even simpler exp. look at a pair of scissors.So,I do not see having the same problem with diffrent size plates.There is no common edge to work against.
As far as using bushings on the tie in.I don't bother.I have never had the body rip at the plates.And yes I have rolled and still didn't have any rips.
 
RockMonkey

RockMonkey

Suddenly Enthusiastic
I don't use bushings on my frame tie-ins. I just weld them right to the frame. Most of the rigs I've built are primarily off-road though.
 
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