Jump to content

6x6 Land Rovers


92.9
 Share

Recommended Posts

I've just been reading up on 6x6 Land Rovers because I'm curious about how they get drive to the third axle. The only method I have seen before involved a rather complicated-looking arrangement whereby a separate propshaft went from (I think) a separate box, over the first rear axle to the second one.

But now I have seen this set-up:

bild015.jpg

bild002.jpg

That looks rather simple. Am I right in assuming that you can get drive to third axle by adapting a second standard input casting/pinion on the opposite side of the official differential input? If so, I wonder why the more complicated option exists.

I got the pictures from this site: http://www.thomasschnell.com/projekte/projekt1.html

Mike

:)

Link to comment
Share on other sites

My guess would be that for the third axle, you would just turn it upside down, then re-weld the brackets on. I would think that it would be much easier to get the brackets lined up properly than all of the difficulties of getting the diff back in place.

A friend of mine did this with a 130, and one difficulty was the amount that the rear prop extended / shortened when each axle went over a bump. I can see that this wouldn't be too much of a problem with leaf springs, but with coils, the deflection is much greater. You have to see it as going around part of a curve - I remember doing the maths for him - I ended up doing lots of drawings.

Link to comment
Share on other sites

because the Oz army ones use Sals diffs rather the the pi$$ weak Rover one.

The weight and carrying capacity of these vehicles I wouldn't want to use a Rover diff, even the 4 pin version that your army uses.

The Australian design uses the pto output on the LT95 and takes it up and over the intermediate axle into the rear diff. The suspension is a load sharing arrangement.

Link to comment
Share on other sites

Both work, cost might be a consideration?

Volvo 6x6s use a similar system as the foley and it works well, Martin the farm monkey has successfully built a couple of 6x6s using the double diff approach and reported no major probs - he did say its by far the cheapest way though! :)

Link to comment
Share on other sites

Thanks for your replies everyone :)

The Foley set-up was the one I was thinking of; I recognize the photos! I bet that's expensive.

Dollythelw, what did Mr Farm Monkey's set up look like? Was a similar set-up to the photos I posted?

Mike

:)

Link to comment
Share on other sites

Guest diesel_jim
Jim, what is that axle off? I don't think I've seen one like that before.

Mike

I'll fling him an email and get an answer.

Edited to add:

Olly replied, saying "Ah just remembered its called a Hotspur, original format was an airfield fire tender. Some how Sandringham springs to mind, i'll dig out tha manual for it"

so there ya go, he mentioned it was a LR special build as well, so a proper conversion.

Link to comment
Share on other sites

Quite a few years back there was a company called Esarco, they made 6x6 and 8x8 vehicles and used quite a lot of Land Rover components.

I think the company changed names 2 or 3 times, if you Google you will find some info out but not much.

If some of you (UK) can remember a program called Driving Force (BBC production). They had both the 8x8 and 6x6 Esarco on the 1989 or 1990 program where the event was held on Jersey around Saint Helier.

Here are pretty much the only pictures I've been able to find of the Esarco:

esarco.jpg

esarco8.jpg

esarco9.jpg

esarco7.jpg

esarco6.jpg

esarco5.jpg

esarco4.jpg

esarco3.jpg

esarco2.jpg

1024.jpg

Link to comment
Share on other sites

As I understand it the Escaro drove out through the PTO hole of the LR gearbox and into that second casing you see which was basically another LR transfer case, of course it's input would be reversed but then so were the two axles it was driving - genius! Looks like they used Rover fronts and salisbury rears.

Link to comment
Share on other sites

Usually,6x6 conversions of existing 4x4 vehicles place the third axle behind the original rear axle of LWB vehicles in order to increase the load carrying capacity of the vehicle. These type of conversions do little if anything to increase the crosscountry capabilities of the vehicles they are applied to, instead of providing a short primary wheelbase for improved rampover angles when climbing up and over steep hummoks, crossing ditches etc, plus a long wheelbase for stabilty and better traction when climbing steep gradients . I built a 6x6 Landey in th late 1970's early 1980's with a wheelbase of 74''+39'' on 9.00 x16 tyres with inverted centrally pivoted leaf spring rear suspension similar to what can bee seen on many tandem drive tipper trucks, giving around 1 metre of interwheel articulation. For drive I used a pinion drop box similar to Foleys conversion on each rear diff. The diffs were turned around back to front so that the pinions faced the rear of the truck.The propshaft from the t/case passed over the middle axle in to the input shaft of the first drop box and another propshaft took the drive from the other end of the input shaft over the top the rearmost axle to the input shaft of the rear dropbox. This arrangement allowed for relatively long level propshafts that could swing up and down further than a short propshaft that is already operating at a steep angle when the vehicle is on level ground.The long straight propshafts combined with twin slipjoints and high angle universal joints in turn permitted the large degree of interaxle articulation.Axle spacing,interaxle articulation, loadsharing and minimal rear overhang on crosscountry 6x6 vehicles extremely important and often overlooked by many builders attempting to improve crosscountry performance, usually resulting in a vehicle performance that is inferior to their 4x4 counterparts. There are a couple of links to my old truck posted by White 90 on one of the last post on ''Bills vehicles'' on page 3 of the Members Vehicles section. The Australian magazine 4x4 Australia did a fairly detailed story on it back in 1983 but I no longer have a copy. The vehicle performed extremely well cross country and on occasions not shown in the videos, seemed capable of doing the ridiculously impossible. However due to the non availability in those years of reverse cut crownwheel and pinion sets, the rearmost differential would break quite frequently. I never had any problems with the drop box gears though. each of them employed half the intermediate gear cluster to two high gear wheels from series landey transfercases to form a train of 3 gears. these were contained in housings of welded fabricated steel, and the forward dropbox contained a dog clutch to diconnect drive to the middle axle. This truck no longer exists, although I still have many of the components lying around in my Landey graveyard. Family commitments, available time, plus older age prevents me from resurrecting the project using reverse cut crownwheel and pinions and applying lessons learned from 5 years of very interesting and enjoyable experimentation with that vehicle all those years ago.

Bill.

Link to comment
Share on other sites

Thanks for the latest replies :)

That was lucky getting a Hotspur axle. I bet those don't become available very often!

The Esarco pictures are interesting. I wondered how they connected the drive on those. It looks as if the front transfer box drives the first and third axles, then the second one drives the second and fourth axles. I think they steered on all four axles too, but I can't see the mechanism - unless that bar running along the top of the chassis rail has anything to do with it.

Bill, it would be a shame not to put your 6x6 back together. When you set up your engineering inventions museum it really should be there too!

Mike

Link to comment
Share on other sites

Guest dew110CSW

I was thinking, what set up does your average 6x4 or 8x4 truck use? I have some pics of the suspension set up off my dads 8x4 DAF it'd be any use but none of the prop arrangements.

Link to comment
Share on other sites

I don't know much about lorries and things like that :). That Esarco 8x8 pictured above has 8-wheel steering too! I read somewhere that they weren't very stable at road speeds.

I'm just trying to think how that would work in practice, if the rear steered as well as the front. I suppose you'd get twice the steering effect for any given steering wheel movement, if the back went one way by as much as the front was going the other way!

Mike

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy