Hilux 4x4 Forum

The 30 year old stock rear bumper on Rooies was very tired and rusty. It also had no way to use it for recoveries. I was beginning to become worried that a trailer might break the hitch point off. So it was time for a new one.

With some input from my engineering mates I designed a new one that has recover points, is directly inline with the chassis rails and looks somewhat stock.
Stress caluculations 10mm plate laser cut by TFD in Strand.

Cut the holes in the rear valance and test fitted the new brackets. Test fitting and tacking the tubes. Going to need to move the number plate... Also got some 3x38x76mm channel to add support inside the chassis rails.

And done.

Looking good!!

What load did you apply for the stress analysis?

Very neat. How are the pipes attached to the brackets?

I don't know what load was applied for the stress analysis, I can find out it you want though.

The pipes were (badly) fillet welded to the tubes. I suck at fillet welds, but I can use a grinder

You know what they say. "If you need to grind your welds then your'e a grinder not a welder!"

Still looks good though.

It would be a interesting discussion topic: Do these recovery holes take into account the load of the vehicle as well as the forces experienced during a recovery?

Lets say for a recovery the forces are 3x the weight of the vehicle (sucking thumb here) and add to that a safety factor of 2?

Your calcs should look something like this:

Vehicle 2000kg
Dynamic weight during a recovery: (x3) 6000kg
Safety factor of 2: 12 000kg

you can halve that value if you recover from 2 point at once, but for peace of mind i would analyse them for the total load on a single point.

I'm not sure about any of these numbers, but its just to get the conversation started?

You're not actually moving the weight of the vehicle, you're overcoming the friction between the surface and the vehicle, so it's a bit more complicated than that.

Anyway, these are mounted far more securely than the old one was. The bumper itself is attached to the channel and chassis rail with two M12 grade 8.8 bolts (normal recovery points are two M10 bolts). The channel is attached to the chassis rail with one M14 8.8 bolt right through the top and bottom of the chassis rail and another M10 8.8 bolt through the top of the chassis rail.