Which Rear Shocks?

redrover

redrover

Well-Known Member
Completely redoing the back end on the Red Rover. Heavy duty springs, rebushing, V8 diff (with new mounts), and fitting new shocks. But which ones do I want?

These
or
These? (And what's the difference?)

Or would I be better with aftermarket/adjustable one? Heard mixed reviews of these and keen to stick to something durable.

Any advice (and experience) gladly received.

Michael
 
Frankly, I'd have said neither! I'm sure Harvey will correct me in a minute, but I was sure V8 and 2000 shocks were different (not sure about 2200 as they used the V8 rear suspension). Something to do with the diameter of the fixing stud and whether it got a nylon sleeve against it on the base unit. And both those offerings appear to be oil shocks anyway. Keith Oxley (the first ad) ought to know the score, why not give him a ring and ask him.

The rear will stand reasonably firm shocks without any effect on the ride - unlike the front! I have seen various of the usual suspects - Armstrong etc - doing gas shocks for the P6, which is obviously preferable. Otherwise I could be tempted by a pair of Spax's or Koni's... I share your wariness of the various Avo etc adjustables.

Chris
 
Okay, that's great info, thanks.

I'd imagine the rear could stand fairly firm shocks. That's evident from the sheer overhang behind springs, so it's no wonder they sag in use!

How or why would gas filled be better than oil filled?
It's just something I have no real knowledge of. I know how and why they work, but not what damping techniques would offer the best qualities, and why.

If it helps when recommending components, the ultimate intention is to finish the back with H Duty springs, new dampers, and rebushed (partly completed anyway) links. I already have the V8 wheels and cranked top links. This will be joined at the front by rebushed bottom links, but I'll be keeping the front springs and top link bushes (until I grow balls big enough to tackle them!). I'll also be uprating the front ARB. Bearing in mind, I don't have the turn-in lurch that kills so many V8 owners, and I don't want BMW stiffness - I like the characteristic P6 roll. I'm only going for H Duty back springs to facilitate towing and heavy loads, and want to even that up at the front with a little less roll. I'll either have an ARB made up, or machine down an 'off the shelf' stiffer one, as I think I'd only be looking for 10%-15% increased stiffness. I believe the V8 one from Classeparts, et al, is +30%? But in either case, I'll fit a fat one and machine down to suit if I feel it warrants it.

Michael
 
May I humbly hijack your thread and ask what puts some people off using the adjustable gas-filled shocks from the likes of AVO, GAZ etc.?
 
mrtask said:
May I humbly hijack your thread and ask what puts some people off using the adjustable gas-filled shocks from the likes of AVO, GAZ etc.?
Click to expand...
I've heard leakage is the problem. But I was under the impression this was only on the front, which act the opposite way to normal. I.e., they are extended on the bump, and compress on the rebound.
 
Gas filled shocks refers to the pressurised expansion chamber inside the shock absorber. The damper itself has a fixed volume of oil inside and as the piston and shaft enter the shock body under bump forces it must displace the oil somewhere otherwise you'd get hydraulic lock.

The expansion chamber allows this to happen - cheap shock have a simple rubber diaphram at the top at atmosphere pressure and in these shock the oil can cavitate behind the piston as the shock is compressed leading to a lack of damping. Gas filled shock have a floating piston separating the oil from the expansion chamber and it's highly pressurised to keep the oil flow consistent through the damper circuits and avoid cavitation.
 
Just done a bit of reading myself. Apparently, all tele dampers are oil (of 'fluid') filled, but the gas type ones have nitrogen in them where the oil is displaced to prevent foaming and maintain a more consistent ride quality over a bumpy surface. From what Paul says, there's more to it than that in terms of the operating principle, but that may be the principle advantage??

Does anybody have any recommendations of dampers they have used and have been pleased with?
 
I have avo ones on the rear of sleipnir. If I had my te again I'd spend the extra and get koni or spax. They aren't consistent if that makes sense...
 
Michael, I am just at the end of this job.

The 2000, 2200 and 3500 where all fitted with different springs, IIRC the details are in the haynes manual. I think the 2000 and the 2200/3500 also have two different types of dampers. 2000 dampers are smaller diameter and the lower link plate is different. I think you can put 2200/3500 dampers on a 2000 by changing the plate. There are also at least 2 different type rubbers fitted top and bottom. Mine had larger diameter some like the ones you have linked to have smaller diameter ones.

I had a second hand pair of v8 unipart shocks ready to fit but wasn't convinced in the end they were both ok. Happy Days gave me a pair of GAZ adjustables to try, he had fitted them to his car and couldn't get on with them. They're in good condition but I'm not convinced either about the wisdom of fitting adjustable shocks to a road car. Its just another variable that's not needed. I've just adjusted them in a vice to give the same damping as standard and marked the dials. I'm prepared to increase the damping a few clicks to compensate for the uprated rear springs but they'll be coming off for a standard set if I don't like them.

I think if you like the ride I'd stay standard. You might improve it with different parts but its more likely you'll make it worse in some way that'll annoy you and decent shocks aren't cheap. I'm hoping as I'm sure you are that replacing 40 year old bushes improves things markedly.
 
redrover wrote,...
Does anybody have any recommendations of dampers they have used and have been pleased with?
Click to expand...

I purchashed my Rover's first set of Koni shocks in 1987, replacing at that time the original factory Woodheads. That set was replaced with a set of Koni Classics around the mid 1990's, not because of any fault with respect of the first set, rather it was down to some testing that I was doing. The upshot being, what ever shocks you choose, run the fronts much firmer than the rears. You'll need to experiment to find the settings that you like the best, but I am sure that you will find that setting will be softer than the fronts.

My Rover has provided a good testing ground for the Koni shocks with to date some 240,000 Miles (386,000km) covered since that first set went on in 1987, and so far they have proven to be totally reliable.
In standard unadjusted form, the Koni shocks are firmer than the Woodheads and the ride noticably better in terms of less wallow and roll, both traits of which I find very unsatisfactory.

Ron.
 
Hi Pat, that's really useful information, thanks.

I'd just finished reading through this post when I read your post, so am now familiar with the difference base plate designs. There is no question I will have the 'domed' 2000 type in my car, as the plates and shocks are clearly original, and the suspension is the proper 2000 one (no cross member). Out of interest, do you - or anybody else - know if 'domed type' means the taller ones? I.e, Is the one on the left is 2000 and the right is 2200/3500?
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If so, does anybody know if V8 types will fit 2000's. Apparently they fit the other way around (i.e. 2000 in V8) but can you put a fat shock in a 2000? If so, I imagine that would be a bit better suited to intentions with a heavy duty springs??

Yes, I think I'm of the same opinion - introducing another variable that needn't be there is just faffing for the sake of faffing. I don't want to alter the firmness of the ride - it suits me nicely, but my current shocks are covered in a thick coating of bran flakes, and my springs are sagging - not badly, but very noticeably if there's a passenger in the back. All bar the leading bushes of the trailing links are renewed, and the deDion is topped up (soon to be regasketed). So all I want (really) is the ability to tow without dragging the exhaust, and a better ride quality than I'm getting with 42 yo shocks.

The NOS KYB ones appeal to me. They have to be better than what I've got now, are the same as what I've got now, and the price is fair.

Another question, does anybody know if there were different shock specs towing spec cars? (i.e., those with heavy duty springs fitted from new?)

Michael
 
SydneyRoverP6B said:
Koni shocks with to date some 240,000 Miles (386,000km) covered since that first set went on in 1987, and so far they have proven to be totally reliable.
Click to expand...

That's definitely a good test of durability then! I suppose the adjustment does have its advantages... but that would probably necessitate adjustable on the front as well then. And I'm just not convinced I'd get the benefit when I still have massive 70% aspect tyres wobbling about on the rims like all steel-wheeled P6s!
 
harveyp6 said:
The shocks are interchangeable both ways.
Click to expand...

Great, thanks. That helps me out a lot.

Any recommendations on whether I should fit V8 spec ones with the heavier duty springs? Would there be any benefit? And is there any difference between the damping ability/firmness of the V8 and 2000 dampers, or it just their physical size?

Michael
 
Can you feel the ride quality changing?
Click to expand...
Yes - i feel like no matter what the setting is it damps then suddenly gives but not necessarily predictably. Never had that feeling on the original shocks ( although they were completely shot.... )
 
I am currently running new heavy duty rear springs and new Spax coil over adjustables, I set them mid way and the ride is harder than a hookers heart, I intend to back them right off in the near future and see if it improves, if not I'll remove the coil over springs. I think my rear end is currently set up for nicking safes :LOL:
 
rockdemon said:
Yes - i feel like no matter what the setting is it damps then suddenly gives but not necessarily predictably. Never had that feeling on the original shocks ( although they were completely shot.... )
Click to expand...
Interesting, thanks. I have to admit, mine certainly don't feel inconsistent. Everything's saggy and creaks a bit, but it's not bobbly, and I'm a frequenter of many rutted country lanes and have always found it very predictable. But like you, they are pretty well shot!

John said:
...the ride is harder than a hookers heart, I intend to back them right off in the near future and see if it improves, if not I'll remove the coil over springs. I think my rear end is currently set up for nicking safes :LOL:
Click to expand...
Haha! Brilliant analogy!

Okay, I'm still open to any advice and experience on this, but a lot of this is pointing me towards thinking that the best option for my needs would be to replace the current rears like for like - with NOS oil-filled dampers. If the current ones still behave roughly as I'd like them and they're rusted to hell, replacement ones will just turn the clock back. Can anybody say that the ride quality (when optimised) of gas shocks is markedly better than oil-filled? Or are we talking the difference of 5 or 10% here? Because the price difference is 200%.
 
Hello.
I have the GAZ gas shocks and I can vary the ride from ludicrous marshmallow bounce to concrete filled!
Im not kidding...twist up the dial and the rear becomes solid!
After quite a bit of fiddling I think I have settled on a setting of "12".
The main "problem" with the shocks is that the dial affects both compression and rebound, so you cant tune each separately.
Furthermore, it doesn't seem to be "linear"...i.e a change on the dial seems to increase compression but does not seem to match an equal increase in rebound. The effect of dialing up the shock is to have very stiff compression that has quite poor rebound control.
I have somewhat "gotton around" the problem by having a bag of cement in the boot...seems to sit and settle the rear quite nicely.
I read in my internet travels that a chap once scientifically tested a whole bunch of aftermarket adjustable shocks and almost universally found huge undesirable inconsistencies in the way they adjusted up as to obviate any so called advantage of "adjustability"
If I could decide again, I would choose Koni Classic...the black ones. Many would prefer Koni Red, but my bias is toward ride.
I returned to stock springs after briefly trying King Springs "uprated rears" (which aren't as "uprated as HD Rover ones).
This well and truly ruined the ride/handling of the car and sat the car up too high in the arse.
The rear is 90% new rubber bushing with only the elbow attachments at the body and the little "panhard rod" (is that its name) with poly.
If I could (and I might) do it again, I would stick with all rubber bushing.
My, albeit limited experience with the suspension on these things is to be very careful with changes too far removed from what the factory had...ride seems to be the first thing to deteriorate...often badly.
 
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