Live axle shock orientation
Turbo Mini Forums

Ever since I first saw a cutaway of a range rover chassis in a book when I was a kid, I've wondered why the rear dampers were oriented with one side facing forwards, the other side facing back. I've seen it a few times on different vehicles over the years too. Right now, I'm sat in non moving traffic looking at the arse end of a pickup, and it's the same...
So, what is the reason for this? And if it's worth doing, why isn't it that way on every live axle vehicle???

if there both to the front of the rear of the axle they will make the axle twist? (dont see how thats an issue on rangeys as they have that big bar that stops the axle twisting) unless its a really old rangey with leaf springs? just a guess lol

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

No RR had cart springs... They all had coils (at least until the airbags), but all had the a frame and links.

Maybe its something to do with anti-roll or something, or for clearance for a panhard rod maybe? Or to longitudinally locate the axle

Capris had this arrangement too.

My opinion is that it was an attempt to control axle tramp, but all you mini fanatics won,t have a clue what that means !

My A35 rear wheel drive has telescopic adjustable dampers but arranged conventionally and the axle is handling about 450% more torque and power than originally envisaged with no axle tramp, so it probably was not a brilliant idea anyway.

Hi Dave,

Now I can't pretend that I knew all this off the top of my head (As I am not that old - honest) But a bit of digging found out.

I was interested in the question as I couldn't think of any sensible reason why this would be so on a live axle with coil springs, I could understand a leaf sprung vehicle but not coils. (Plus every classic Range Rover I have seen with coils has them both on the same side)

OK, the bit that I do know is that on leaf sprung live axles (as you no doubt know and what has already been eluded to in this thread) we get the tendency for it to develop into an 'S' shape under a variety of conditions,

One is under power and this manifests itself as axle tramp.

Another is that this happens during impacts, (by impacts I mean say a pot hole strike or anything that the tyre hits which is like an 'edge' or a shallow kerb.) In this instance (depending on a variety of the things, geometry of the leaf spring / rate of the leaf spring / inter leaf damping / axle mass etc...) we get an NVH problem called 'shake'. (They have lots of different NVH terms shake / chop etc depending on the frequency of the NVH issue)

In this specific instance the dampers are one in front / one behind because of the NVH 'shake' issue, it is not a problem on all leaf sprung vehicles as the stuff I listed above is different vehicle to vehicle and some suffer from it some don't. > Hence not all leaf sprung vehicles have this layout.

This doesn't answer why you saw a cutaway of a coil sprung Range Rover with this layout, the answer is less intuitive, for about the first 6 months of manufacture the Classic Range Rover used 'carry over' rear axle parts (i.e. from a leaf sprung vehicle) which had this layout, thereafter they went to the both dampers on the same side of the rear axle as I would expect to see with a coil sprung live axle.

Still awake :)

Cheers

In the ariel view of the RR chassis, you can see the shock orientation.

This is from the 1980's, witness the twin pipes on the exhaust. It can be seen that the RH shock points rearwards, the LH is forwards.
http://www.range-rover-classic.com/Home/ra...ange-rover-1980

Another view (the one that confused me 30+ years ago, and still bugged me LOL).

http://www.landrover-center.com/sites/defa.../news_399_2.jpg


I do know that the RR's used axles very different from the landrovers, even on the velars. These were all-new for the RR, at least having a wider track than any land rover axle with the exeption of the Forward Control, which had initially Rover axles, and laterly ENV axles on the 11b...

It is interesting that they changed sometime in the 1980's however...

Nice to have such a comprehensive explanation - especially of the Range Rover apparent anomaly -thank you.

Cheers Tadge,

It was interesting to hear the story first hand and made me smile when I was told it, I have heard plenty of Austin Rover / Rover stories over the years but this was a new one on me.

Hi Dave, (Sorry editted to death after I first wrote this, so I rewrote it, don't trust information you get from others...)

As I say the RR History part is not my interest, just the chassis dynamics bit.

I spoke to two current LR chassis / development engineers, the first one told me about the carry over rear 'axle' (which I now think he meant carry over 'concept' - i.e. the forward / backward damper) but wasn't sure when they changed. The second discussed the development of the velars (A name I hadn't heard before a few days ago!) and repeated that the fore / aft damper angle changed later (he thought it was much earlier)?

I am not at all familiar with the physical parts myself but got the same explanation from the two LR engineers independently... However after 'Googling' I have to agree I have seen lots of images of later cars show the backward / forward layout - Indicating the change was 1985/6?

As I say my interest was spiked when you mentioned by the coilover layout with this forward / backward damper on a live axle which didn't make sense to me and was why I dug deeper, the History part I passed on as I thought it an amusing anecdote but I have no interest either way with the chronology.

Cheers

Please let this thread slip away and with it my embarrassment about the changeover dates I was given

Edited by Aubrey_Boy on 19th Aug, 2014.