TheSamba.com :: View topic - pre-runner front bumper

Sat Feb 05, 2005 6:49 am

my ol baja has a single tube front bumper. anyone have any photos of some trick pre-runner front bumper/skidplates? thanks for your help.

Sun Feb 06, 2005 9:20 am

bump.

Sun Feb 06, 2005 1:53 pm

I am not sure what your looking to build, but here are a few that I like.

SHMO

Sun Feb 06, 2005 2:59 pm

thats what i'm talking about... i like the last two for sure. the first one looks like it came of a santa fe steam locomotive or something, but that guy can knock down anything in his way! next thing i'm gonna need is a bigger motor to lug around all this extra tubing i've been adding! maybe kona could build me an engine.

Mon Feb 07, 2005 1:42 am

The last one is mine, and it was pretty simple to build.
SHMO

Mon Feb 07, 2005 6:57 am

I'm bulding a similar bumper soon.
SHMO- is that 1.5 inch tube on your car? What do the upper tubes tie to? the body I'm guessing.. How about a pic with the hood open to see your attach details?
Perry

Mon Feb 07, 2005 11:34 am

Here is one I plan on copying on my 65.

http://www.desertrides.com/features/vehicles/sack_class5/imagepages/DSC00814.php

Desert Bob

Mon Feb 07, 2005 12:46 pm

My bumper is built from 1.5 inch tubing with 1-inch tubing for the upper supports. The bumper ties into the beam on the bottom, and on the top it runs into my rollcage making it pretty stout. That is the reason for the smaller 1-inch upper supports. I wanted a bit of a crumple zone so that the bumper would give before the rollcage if some major push came to shove. I will try to snap some pictures of the underhood area.

SHMO

Mon Feb 07, 2005 3:43 pm

Here are a few more detail pics of my bumper.

SHMO

SHMO

Mon Feb 07, 2005 3:47 pm

this pics will kind of give you an idea about how I mounted the bumper. I hope this makes sense.

The red lines represent where the rollcage runs just below the level of the trunk. The cage also comes in from the bottom of the car. Both parts of the cage meet at the axle beam, one ties into the lower beam tube and the other to the upper beam tube. The bumper connects to the lower beam tube and also ties into the upper portion of the rollcage, just below the level of the trunk.

SHMO

Tue Feb 08, 2005 9:22 am

thanks for the detailed reply!
That looks pretty similar to what I would like to do with mine. I plan to run the cage in a similar fashion up front, and tie to it. Good idea on the lighter tie back tubes for crash protection, I'm considering a little kink in the 1.5 tie backs and a few strategically drilled holes. I want to stay with the heavier tube though, I tend to really abuse bumpers on the trails around here.
Perry

Tue Feb 08, 2005 10:47 pm

Personally, I would stick the the smaller tube for the bracing. It is going to provide you a better knowledge of its actual strength. It would be a shot in the dark by weakening the larger tube with holes and kinks. I mean you would never know how weak those holes and kinks actually made it, until it was lying in the road in front of you....lol

If you think you really need an indestructible bumper, make it all from 1.5 inch tubing and let the rest of the chassis take it on the chin. But, keep in mind that it is much easier to bolt on a new bumper than it is to fabricate a new cage.

SHMO

Wed Feb 09, 2005 11:13 am

The point is not to know the forces it would take to break, it's to make sure that when enough force is applied the weakest area to crush first is not the area you're sitting in..
I think I'll just use bolts in shear as attach points. this is used on farm implements quite a bit and is about the most accurate way to build in a break away point. I plan to have the bumper bolt on anyhow, so I'll just be careful about the attach point design and calculate the hardware for 3 or 4 times the weight of the car.
There are also some white papers that discuss the use of wedges at the nose to deflect an impacting object above or below the car.. they recommend designing such that the wedge'd car goes under another on impact because it will stop the car in a safer manner. on a baja with a prerunnner style front bumper like yours and soon mine, in a serious accident we will probably use the other car as a ramp more than anything.. unless it's a truck..
Anything with a tube bumper around my house becomes a tool to push stuff with.. and the more serious trails around here are often near ledges that occasionally a vehicle will fall into and have to be dead lifted out with cable.. so i like to have strong attach points.
Perry

Wed Feb 09, 2005 12:14 pm

It sounds like you have it figured out Perry. Post some pics when your finshed.

SHMO

Mon May 09, 2005 7:11 am

bajaherbie wrote: thats what i'm talking about... i like the last two for sure. the first one looks like it came of a santa fe steam locomotive or something, but that guy can knock down anything in his way! next thing i'm gonna need is a bigger motor to lug around all this extra tubing i've been adding! maybe kona could build me an engine.

Sure I'll build what ever you want :D

Mon May 09, 2005 3:30 pm

kona, what are you doing slumming around in the old baja threads??? :D maybe one of your soldiers told you about this post...... btw, i fabbed up a new front bumper, and the old motor is doing just fine 8). maybe i'll call you for a trick motor when this ones pops. :roll:

Mon May 09, 2005 10:03 pm

bajaherbie wrote: kona, what are you doing slumming around in the old baja threads??? :D maybe one of your soldiers told you about this post...... btw, i fabbed up a new front bumper, and the old motor is doing just fine 8). maybe i'll call you for a trick motor when this ones pops. :roll:

You can't stay at the top all the time, ypu gotta see what the little people are doing every so often. I'll be standing here with wrench in hand waiting to build you a motor.. :shock: