Thread: Salisbury Diffs

Basically, the reason is that it has not been seen as necessary. The salisbury diff is stronger than the Rover one for a variety of reasons, but it is also quite a lot heavier, and more expensive, as well as being more difficult to work with. A further problem is that the longer nose on the salisbury may cause problems with the front prop shaft, which is a lot shorter than the rear one, and there may also be issues with the track rod. Increased unsprung weight is always a problem, affecting adhesion, handling, ride, and increasing general wear and tear - just because we have already got relatively high unsprung weight with solid axles, does not mean we can ignore the effects of even more!

The maximum load on a diff is dictated by the axle loading, everything else being equal (when the tyres slip), and it is a simple fact that the axle loading on the front of a 110 or 130 is a lot less than on the rear (at maximum load). The Rover Diff has been used successfully for years in the rear of the 90 and the perentie 6x6, in both cases with lower axle loading. This shows why it is not necessary to have the same strength axle front and rear. Note that with the centre diff unlocked, the front wheels would be expected to slip first(again, everything being equal) but with the centre diff locked, there will be drive to front and rear in proportion to the weight on the axles up to the limit of adhesion. Of course, in practice, the grip on all four tyres is never the same, so the one with the weakest adhesion will slip first - but even if this is a rear one, and it slips at a much higher load than the front due to the higher load, the front diff will still not be as high, as the front wheel will also slip, as it has less weight on it. (This analysis assumes the vehicle is loaded - if unloaded the extra strength of the salisbury is not needed at the back, but then the load on the front is no higher than it would be if loaded - probably less, even though the weight bias is now to the front)

The Rover front diffs can break, particularly with the 4BD1 engine (which is a lot heavier than any other engine fitted), but usually only in extreme conditions or after long use.

I have never seen one fitted to the front of a Landrover, but I would be surprised if someone had not done it. Note that the Series 2/3 One Ton 109 had ENV diffs front and rear, at least optionally. Late models had salisbury at the rear, but I am not sure what they had at the front.

<div class='quotetop'>QUOTE</div><div class='quotemain'>I have never seen one fitted to the front of a Landrover[/b][/quote]

Salisbury Fronts were factory items on some Landrover special editions, both series and 110s, and of course 101s. They were used infrequently though, mainly for armoured vehicles & such. They are now sought after and are like hens teeth, commanding a high price. Their value is not so much in the load carrying ability for which they were originally built, but for their R&P strength, being able to cope with a great deal more HP than the relatively weak Rover diffs.

Some interesting stuff about Salisbury front axle here:

http://www.red-ibex.com/Salisbury_front.htm


Paul [img]style_emoticons/<#EMO_DIR#>/biggrin.gif[/img]

Originally posted by Defender200Tdi
<div class='quotetop'>QUOTE</div><div class='quotemain'>I have never seen one fitted to the front of a Landrover

Salisbury Fronts were factory items on some Landrover special editions, both series and 110s, and of course 101s. They were used infrequently though, mainly for armoured vehicles & such. They are now sought after and are like hens teeth, commanding a high price. Their value is not so much in the load carrying ability for which they were originally built, but for their R&P strength, being able to cope with a great deal more HP than the relatively weak Rover diffs.

Some interesting stuff about Salisbury front axle here:

http://www.red-ibex.com/Salisbury_front.htm


Paul :D[/b][/quote]

Thanks for that Paul, very interesting indeed. I note that as I predicted, there are problems with both the track rod and front prop shaft. Question - would it be feasible to adapt a rear salisbury axle to the front? What I mean is use the outer ends off a standard axle and weld a centre from a salisbury in to it. Obviously a major undertaking, and dimensions and alignment would require building jigs etc to reach the necessary accuracy. Are the half axle splines and lengths the same as the Rover axle?