I am planning a custom rear bumper for my 98 100 series and would like someone to explain why all the bumpers I see available have two shackle points on them. Why is a receiver shackle not sufficient. I understand it's function on the front where I have a winch to run out and back to the vehicle but I will not have a winch on the back. Is the issue strength? Could a custom built bumper have the receiver reinforced enough to use a "super yanker" recovery strap safely?
Basically most rear recovery points are tied into the frame rails. A receiver system would probably be sufficient for most situations but only as strong as the pin (which is pretty strong) but a shackle pin is larger.
Having two is a little more versatile. Or if you need a rear point while a trailer is connected. Slee's Jac-kof tool uses a shackle tab if you like a secure Hi-lift jacking point. You'll find uses if you have them.
Corbet,
I can understand the strength advantage since my 4x4labs on my 94 has the attachment points as you describe. Makes sense to pull inline with the frame rail rather than 90 degrees to a custom square tube in between the frame rails.
So far I have nothing to tow offroad and I want the bumper to be "open" so my hi-lift would still work, but I appreciate the point you made regarding strength.
Depending on what you are doing you may want the point of connection to be on one side or the other of the center of gravity (eg. in the case of trying to prevent a rollover) As stated above, the strongest points on the bumper are closest to the frame rails.
With regard to your hi-lift comment, I built a rear bumper (and now I am working on a front bumper) with hi-lift pockets integrated into them so that I do not have to worry about how to get that jack to stabilize holding up the truck. A section of 1.5"x2.5"x0.120" rectangular tubing cut to about 1.75" long is about perfect to capture the hook end of a high lift and prevent it from slipping out.
I believe there are distinct advantages of having multiple attachment points. Although I always have a hitch mounted ring, on several occasions it was better to recover from my OEM frame mounted recover loops. This had to to within alignment of the winch line between the two vehicles when pulling sideways.
-Nick
-D/D is a 1985 tan FJ60 with a 350 SBC TBI, ARB front bumper, Tuffy center console, Non-USA OEM Split rims, Yokohama Y735B 7.50 R16, Confer roof rack, and a box full of archaeology field work gear.
Different attachment points can offer advantages in any specific pull. Particularly off angle pulls on off camber rigs.
Multiple attachment points come in handy for multiple line pulls and also for multiple winch pulls. Or for attaching additional lines just to stabilize a rig while it is being winched.
Or for attachment other than winching. Transport tie down for example. If I'm trailering long distances over high speed but rough roads I prefer to use four connection points to tie the rig down by the axles and four to tie the body/frame down as well.
I generally have a (primary) center recovery point on my front and rear bumpers (preferably a pintle hitch) and two points aligned with the frame rails (either D rings or clevis mounts).
