Seatbelt anchor mounted on cage?

Jeffncs

Jeffncs

Well-Known Member
Joined
Apr 4, 2017
Location
Wake Forest
I’m installing an 6-point cage into my early bronco. It’s been a while so I did a little refresher reading on cage design. I am aware that drilling through the cage and mounting a bolt is a strong “NO GO” without adding a sleeve.

With that behind us, do you prefer:
Full width threaded bungs (welded on front and rear sides of the cage tube?

OR

Short threaded bungs that weld to the front side of the cage tube?

OR

Unthreaded sleeve through the cage tube welded at the front and rear of the tube? (Bolt goes through this tube; uses a washer and nut to secure it)

OR

Weld tabs to the strategic locations on the cage and mount seatbelts using grade 8s?

Cage is a 6-point, 2” od, family style that will tie into the frame at 4 locations, possibly 6 depending on access to the frame in the front. Seats will mount to the floor, which is why I’m tying the cage to the frame so its all tied together for safety.
 
I've used these:

motobilt.com

Seat Belt Mounting Bung for Round Tube

The Motobilt steel seat belt bungs are used most often for the shoulder mount of your seat belt but can be used for a variety of reasons. These are designed to fit 1.75" tubing by simply drilling a through hole and the lip on the end of the bung keeps the bung from pulling through. The thread...
motobilt.com

Drill a hole straight through the tube, weld both sides. The back side is also flared to resist pull-through. Probably stronger than factory.
 
Adding a follow-up question…. With the seats on the floor, can I use the floor seat belt mounting holes or should I add a lower crossbar onto the B hoop and tie the belts into the cage at all 3 points?

This truck is for ice cream and casual trail rides. Bronco 2 will be more purpose built for trails first and ton cruises second.
 
On a early bronco I’m helping with, with 4 pt retractable h style seatbelts,

We added tabs onto the seat brackets for mounting the belts.

This way if the seats are removed the belts come with them.

The seat brackets are a mix of 1/4” and 3/16 steel bolted thru floor with bigger plates under the floor to spread out the load.

Same useage. It’s a restó-mod style build not a more hardcore crawler with a 6 point cage.

Otherwise for full cage and harness use I use quick connects for belts and these weld on eyelets for mounting and quick removal for cleaning.

IMG_4956.png
 
You said you were going to tie the cage into the frame. Is it tied into the floor as well? Like does it have plates sandwiching the floor?
 
I did tabs... on the cage (what seats are mounted on)... in pairs... cause interwebs preaching "double shear" ("needs more triangulation"/"hit it with your purse").

Pretty sure I used Grade 8's as well, knowing they are less resistant to shear than Gr.5, so hoping 2- 3/8" Gr.8's in double shear wasn't a mistake 10 year ago?
 
I decided to buy bungs to weld into the cage tube. I plan to use them at the high shoulder and exterior lap positions.

If I decide to run a floor tube from side to side on the B hoop, I’ll add another bung for the interior lap. Otherwise, I’ll use the factory seatbelt mount holes.

I’m tying the cage to the frame in 4 locations (A and B hoops) so anticipate the frame-body-cage will remain a single unit in the event of a crash or roll. The C hoop tie-in would be very difficult to establish due to rear leaf shackle interference.
 
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