Slackdaddy

Just about 100% of aftermarket and home fabbed bumpers are made heavy duty, 1/8" plus plate steel. I see no collapse or energy absorption built into them.
Looking at how easy it is to "total" a XJ with a bent or buckled "uni-body frame",, I would assume even a very, very minor bump would send the energy straight tru the after market bumper into the frame,, buckling it?


Thoughts?


Slack

00t444e

Most of the aftermarket bumpers come with tie in brackets that stiffen the front frame area for this reason.

Slackdaddy

But something has to give, somewhere,, That just pushes the damage farther back.


If you have 2000# rolling along at 10MPH and it hits an immovable object,, that 2000# times 10MPH is a LOT of energy,, and with the aftermarket front bumper built like a tank, and the front 18" of the Uni-frame reinforced, where's the energy going?


Reason I bring this up is: My son and I are putting well over a year into this build and we are talking about bumper builds and came to realize the way we build bumpers would destroy the XJ uni body in a small "fender bender"

00t444e

I guess it depends on what you hit, if you ran into something solidly anchored like a pole or a wall then you would probably do more damage with an aftermarket bumper, but hitting a deer you would be much better off with a solid bumper.

Martlor13

What are you hitting hahah? Rock or tree is all that comes to mind. In a fender bender, the heavy duty bumper is gonna destroy sheet metal, lessening the impact.

bad_idea

The same thought passed through my mind (quickly) while I built the bumpers on my XJ. I look at it like this: You want the bumper tough to hold up to recovery efforts when (not if) you get it stuck. I make it a habit not to hit things at high rates of speed. IF I do hit something (or something hits me), then XJs are a dime a dozen and I'll buy another roller for $400 and swap my parts over. I have smacked things on the trail and the bumpers suffered no damage, if I had stock bumpers they would have dented. Basically an all or none approach.

89eliminator

the ARB bumpers are made to absorb impact

00t444e

They also absorb all the money out of your wallet when you buy one.

BooGTS

I ran frame stiffeners when I put my rear bumper on because of this - that and my "frame" sections were suffering from 17 years of Ohio/Michigan at the time.

My interior came from a Jeep that was rear ended and the complete body buckled in the rear wheel arch area. They're weak compared to a more modern vehicle.

mannydantyla

My mom's Cherokee was totaled (bent unibody) when it was rear-ended by another vehicle on the highway. Thick fog, traffic in front of her was stopping, I don't know how slow she was going and how fast the other driver was going I wasn't there...

That was a stock bumper.

Point is: whether or not you have stock or aftermarket bumpers, the XJ is vulnerable to bending without frame stiffeners.

vulcan96

Its not about it moving the damage back,or that something has to give, it is about making alot of things have to give at the same time, it is about distributing the damage over a larger area to spread out the force.

Another way to look at it ... Is say you get hit, or hit something at an angle on one corner or the other...
An aftermarket bumper is going to transfer that energy through the entire unibody, a factory one is going to smash into the fender, then into the inner fender, then into the.... you get the point.

In any case an aftermarket is going to disburse the energy over a much larger area than a factory bumper. In my opinion that is a good thing. No matter the speed of impact.
The less energy is isolated the less damage it will do.

Perfect example.. Try to do a pushup on your fingertips, then palms down.