bill van snorkle Posted May 20, 2009 Share Posted May 20, 2009 Yes, adding axles is only effective if the axles are load and torque balancing to ensure that there is adequate and even contact with the ground for traction. Vehicle weight and floatation is also an issue hence mine only had 7.50x16 tyres and not 9.00x16 or bigger. Even then I was running at best part of 2.5 tons unladen. Traction with an extra ton plus in the back was really rather good!The downside of having an extra axle is the effective overhang for loading. The balance point over the rear wheels moves from being the rear axle to being the pivot between the axles so some 20" further forward. Important if lift towing or loading right at the back of the load bed. Weight there effectively unloads the front axle. I was looking for heavy and grippy for flat towing and pulling on and off road more then ultimate off road though I did also want it to be able to climb and articulate over rough ground too. A Centaur half track would have been a nice alternative... Your comments re effective overhang reminded me of another factor to bear in mind for anyone designing for maximum offroad mobility. On a 4 wheeled vehicle or a multiwheeled one with non interconnected rear suspension, the departure angle as measured on level ground is fairly close to the angle the vehicle will climb or descend before the rear end makes contact with the ground. This is not the case with an articulating rear bogie and the actual departure angle, depending on drive system employed can be considerably lower than the angle measured on level ground, so overhang should be kept to an absolute minimum to prevent hanging up on the rear crossmember. As you stated in your last post, modern differentials are a bit bulky for making bevel boxes from. Some of the earlier bolt together split case diffs from the 1920'to 40's were quite narrow and more easily adaptable, but as you mentioned ,sourcing a sufficient quantity of suitable but long obsolete components could be difficult. Worm drive diffs from earlier 1950's 60's Peugots also looked attractive as I recall, either as a relatively simple means of attaining tandem drive from only one rear transfercase output or as a possible alternatives to bevel boxes. I'm not certain how happy the worm shafts would be about being driven by the worm wheels however when positioned at the walking beam pivots. Bill. Quote Link to comment Share on other sites More sharing options...
NRS91 Posted May 20, 2009 Share Posted May 20, 2009 this thread makes very interesting reading i suppose if you could get the gears then it would be possible just wondering does anybody know the length of the short side axle tube on a range rover rear axle? Quote Link to comment Share on other sites More sharing options...
bill van snorkle Posted May 20, 2009 Share Posted May 20, 2009 this thread makes very interesting readingi suppose if you could get the gears then it would be possible just wondering does anybody know the length of the short side axle tube on a range rover rear axle? I can measure it tomorrow if no one else comes up with the answer beforehand. The video of the 6x6 101 I mentioned on a previous post is on Google Video not You Tube as I thought. try this. http://video.google.com/videoplay?docid=2431106815226648783 On the first and second attempt at the dune the rearmost wheels appear to bog down whilst the middle wheels, barely touching the ground are offering very little traction at all. On the 3rd and 4th attempt the vehicle is see sawing on the middle wheels due to the weight of the airborne rearmost axle and the weight the body section behind the middle axle unloading the front wheels A more articulate suspension would have idled over that dune. Bill. Quote Link to comment Share on other sites More sharing options...
NRS91 Posted May 20, 2009 Share Posted May 20, 2009 thanks bill if its around the 20" mark i might be able to get away with my idea Quote Link to comment Share on other sites More sharing options...
Night Train Posted May 20, 2009 Author Share Posted May 20, 2009 thanks billif its around the 20" mark i might be able to get away with my idea Are you thinking of real building or is it going to be a vapour build? I would be interested to see what you do if you start metal bashing. WRT the rear overhang, on my 6x6 the chassis was the same length as the standard 109" chassis. The rear axle centre line located just below the rear crossmember withthe bogie centre line close to the original rear axle position. This meant that the rear cross member, and tow hook, could never ground out. The rear body work over hung only a bit behind the back edge of the tyres with the body supports sloping back to the crossmember at 45deg. The over all wheelbase was extended by pushing the front axle forward to the front bumper position so, again, no over hang. Quote Link to comment Share on other sites More sharing options...
NRS91 Posted May 20, 2009 Share Posted May 20, 2009 well at the mo till i get any fab skills or money its pure vapour... im working out a plan in my head and when i can afford 3 rear axles and 4 90 degree gear boxs ill probs do it... till then im just gna keep thinking gears... the rotation should work out correct too... would need to find a place to make a 1:1 diff ratio (if at all poss) and get my mate to weld the other two axle diffs up Quote Link to comment Share on other sites More sharing options...
bill van snorkle Posted May 21, 2009 Share Posted May 21, 2009 RandyLandy,,The distance from the centre of the diff bowl to the outside flange of the axle tube on the short side is 22 1/2''. Bill. Quote Link to comment Share on other sites More sharing options...
NRS91 Posted May 21, 2009 Share Posted May 21, 2009 nice my plan could work out rather well then by the way ... my names nick the forum name is something i made up when i was young a stupid Quote Link to comment Share on other sites More sharing options...
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