Has anyone added another axle to the rear of a 712?

[audiocontr]

Just curious if anyone has hacked on a 3rd rear axle?

[TechMOGogy]

I have only ever seen an 8x8 Haflinger

[compunerdy]

That is a cool idea.. It would be easy to do would it not?

[cascade.king]

A bit rough to steer, though.

[GenevaPinz]

Just adding an extra axle at the rear would be relatively easy IMHO, maybe except for the suspension (how would a coil spring 710-like suspension get along with the stock leafsprings of the original 2 "middle" axles?).
But I have read repeatedly that the rear 2 axles of a 712 tend to push the truck in a straight line in some circumstances, so I wonder if the front wheels would stand a chance steering an 8x8 Pinz with 3 fixed rear axles, especially with the added rear axle having extra leverage.

If I am not mistaken, the 8x8 Haflinger has steering on both front axles. I would think that modifying a Pinz in such a way would require major modifications... (especially if you want all axles evenly spaced like the Hafi, meaning you need to relocate not just the gas tank and batteries but probably also the transfer box...).

[TechMOGogy]

SNIP...
If I am not mistaken, the 8x8 Haflinger has steering on both front axles.

That is correct plus 1 of the rears I believe - nothing to go wrong with that modification

[Haf-e]

The 8x8 Tatras have inter-axle differentials to allow for different axle speeds when turning - that wouldn't be possible with a Pinzgauer. I think adding an additional front axle might be easier in some ways with extending the body forward - but the steering would need to be worked out and power assist would be required.




If a third rear axle was used it would probably need to be steerable in the opposite direction.

[Haf-e]

The best reason for a 8x8 is the ability for it to cross ditches and gaps - they are able to self "bridge" gaps since one of the front set of wheels will always be in contact. This is also possible to do on a 6x6 with more evenly spaced axles.

I've always imagined a 6x6 pinz with two front axles and one rear might be the ultimate - this is what a lot of the Tatra trucks use in the European truck trial competitions. Especially true for vehicles which are not carrying heavy loads in the back.

[Profpinz]

According to Egon Rudolf in his book "PUCH", in 1964, SDP Engineers played with the idea of building an 8X8 Pinzgauer.
The looked at using the rear assembly (complete with inverted leaf springs) of the 6X6 setup at both the front and rear of a backbone but fitting four steering axle tubes to the front units.