6-wheelers (offroaders and lorries) and transmission wind-up?

Its the usual way to do 6x6, as the axles are close enough together that there is minimal windup between them. The commercial side tends to do it by having a pass-through mid axle, which has an extra output from the back of the diff, with a short prop linking to the rear axle. The amount of difference between the two axle speeds is negligible, the main difference when going round corners is experienced between the front axle and the rear pair, especially as the front axle has two wheels both turning at different speeds when going round a corner. The only downside can be a tendancy to wear out the tyres on one of the rear axles quicker than the other, but this is usually only experienced in vehicles which have 6x4 or selectable 6x6/6x4/6x2.

Alex

That's the way the Pinz does it, I'd imagined that it would have a selectable transmission link similar to the one between front and rear axles giving it two wheel drive on the road, but I couldn't see it on the chassis between the rear axles so looked into it.

Pinz has selectable 6x4 and 6x6 with cross-axle diff lock on all axles (rear two are locked together, front can be locked independently). I'll check up on tyre wear but I don't think it's going to be an issue worth fretting about.

Cheers for the input.

No the front drive axle has a inter axle diff (lockable) and lockable diffs in each drive axle

I think what Alex was saying was that on most six-wheeled commercials, the first rear axle has a "pass-through" diff on it, in that it takes power in from the front and then passes it through to the second rear axle. The pinz also has this, but adds front-wheel drive and lockable cross-axle diffs to the equation, which is what you're saying.

In summary though, it seems to be a common layout and I don't need to fret about transmission wind-up between the two rear axles under normal road-going conditions.

On or around Thu, 30 Mar 2006 11:49:23 +0100, Ian Rawlings enlightened us thusly:

git...

Did I mention the three cross-axle diff-locks?

And the build quality?

Costs the same as a decent second-hand Defender, about £8k. Yum.

Parts costs on the other hand.....

This set up is used on some 'on-road' six wheelers but many have a 'power dividers' or centre diffs between them, usually integrated with the forward rear diff. I have been involved with both and the one without the diff is certainly less trouble prone. Transmission wind up is in itself no problem (if considered at the design stage) and is much lower than with a 4x4 because the two axles are a lot closer, and is resolved simply by tyre slip, with resulting higher tyre wear - but a six wheeler drags the wheels sideways when turning anyway, so it probably does not make much difference.

It is of interest to compare these two options with the 'perentie' Landrover

Cheers for that, useful info. The pinz is an old design, around the series 2 landy era, nothing advanced.

I've read about a number of different solutions to the 6x6 landrover, the above seems like a good solution especially if you consider the issues of having a rear set of four driven wheels joined by a fixed shaft, with the front joined by the differential. You'd end up with the rear four getting half the engine's torque and the front two getting the other half. Probably easier just to do the above!

The pinz on the other hand doesn't have a diff between the front axle and the rear axles, just a series landy-style selectable link. It is a 1970's vehicle after all. The four-wheel pinzes are two-wheel-drive on the road.

A lot of the suspension and brake components will be commercially available. The engine will be something readily available to the commercial market, you just have to find out what else it was fitted to and go to a commercial motor factors armed with part numbers and vehicles.

A bit trickier to get parts for, certainly, but if you use your noodle you can save significantly.

Alex

BTW, I take it you've bought an older one, about 1975-1979 if you paid £8k.....

Alex

Good movie of the current generation Pinz on Stewart&Stevensons website (Uk importers/dealers/MOD suppliers)

I've not bought one yet, and won't do for about 6 months at the very least, I need to rustle up about £4K first then flog the landy for about the same. I've got enough loot in the bank to buy it and keep the landy at the moment but that's an emergency fund in case business plans go wrong, very tempting to blow some of it!

I drove one on Wednesday, a 1973 model, in top-notch condition. It was bought by a company who make armour for vehicles, they were going to use it to develop armour for the pinz but Pinzgaur UK found out about it and sent them a brand new model for free, which they promptly blew up...

For a 1973 vehicle, it was absolutely immaculate, real quality metalwork, dry as a bone underneath, the floor of the garage where it had sat for four months without moving was clean as a whistle.

The springs and shocks might be shared between other vehicles, but the rest of the suspension isn't. Cheap bits are likely to be common between other vehicles, it's the bigger metalwork that's serious cash, unsurprisingly. Inside the brake drums is likely to be pretty common stuff. It's not bank-breaking stuff though, mostly perhaps 50% more than the equivalent bits for the landy. Hard to get second-hand though.

The engine is a specially-designed air-cooled straight four 2.5 litre petrol, it uses common carbs (either stromberg or webber, can't remember). The newer machines use a specially-designed diesel, however it was designed by VW so probably looks quite familiar.

All spares are apparently available for the vehicles, some re-manufactured as is common with vehicles of this age, old landies and old lotuses are similar. There might be some parts that you can't get any more, usually small parts that you throw away then realise that you can't get any more ;-)

Yeah, not bad. For £8k you can get the same machinery just with an engine that's got half the power, a manual 5-speed instead of an auto four-speed, no power steering and drum brakes instead of disc. I reckon that's good value for money. The six-wheeler is about a foot longer than a 110 and about the same height. You can probably tell why I'm interested, it's got the charm of the series landies too.

Sounds familiar - the NZ Army have recently bought a load of Pinzgauers, all of which started suffering from terminal problems and most of the fleet has been parked up since pending a factory modification. Still, it means there's about to be a load of Stage 1's for sale :-)

Well, I think they're made in Britain now ;-)

On or around Thu, 30 Mar 2006 21:40:15 +0100, Alex enlightened us thusly:

only works in IE. crap webdesign to the fore again.

I just fed it to wget then to mplayer, which I routinely do with links to actual video files rather than to the ever-useless in-page players.

On or around Fri, 31 Mar 2006 07:55:27 +0100, Ian Rawlings enlightened us thusly:

I need to sort mine - bloody nero showtime grabbed the filetypes and is even more crap than windows meejaplaya.

Mind, a 6x6 Pinzy would make a nice minibus...