New suspension for def 90

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davidrtaylor
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New suspension for def 90

Postby davidrtaylor » Wed Jun 26, 2013 3:58 pm

Looking to replace my suspension.
Looking at +2" all round with dislocation.
What the best setup for around £300-£400.
Defender 90 tray back 2.5t
Defender 90 bobtail with tray back 2.8 daihatsu.
Shogun V6.

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davew
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Postby davew » Wed Jun 26, 2013 5:08 pm

Springs

+2 inches is pretty vague, it's only used as a marketing ploy. +2 inches compared to what exactly ? A typical salesman would tell you 2 inches taller than a standard 90 but there's no such height as the height of a 90 differs from model to model and what weight you are carrying.

I'd suggest you try and get a measure of where your motor is at at the moment, in terms of ride height, and work from there based on how much higher/lower you want it.

Most of (if not all) the aftermarket +2 inch kits claim to give you +2 inch over a standard vehicle - if you can figure out what height a standard vehicle is supposed to actually be ! The way they achieve that is normally by keeping the springs at the same length as standard and making them ridiculously stiff. Stiff springs lift your vehicle but give a harsh ride and prevent the axle moving upwards as much, reducing your articulation. It's too easy to over look the fact that a good portion your articulation comes from the upward movement of the axle. If the spring is too stiff you can lose that portion.

What you really need are soft springs that have a longer free length or progressive springs.

Land Rover red/white springs are often a good match for one end or the other (sometimes both) and genuine (isn) Land Rover springs are often cheaper than dubious quality after market ones. Red and Whites are part number NRC4304 - genuine are around £45, aftermarket (allmakes, bear mach, britpart) around the £16 mark. Roughly speaking the Red and White is about 40mm longer than a normal rear spring but is the same weight rating (around 3000kg/metre).

I have a pair of Red/Whites in the garage if you want to try some and see where it puts the ride height. That will also tell you the sprung weight at the corners you try them on. Once you know the sprung weight you can choose springs that will give the desired ride height at each corner. I have a spreadsheet that has most of the available springs in it and calculates a ride height for each spring based on the sprung weight.

You only need relocation cones on the rear. As long as you have a shock absorber going through the front springs they can't really go anywhere even if you did manage to dislocate a spring (something you'll only do with a very stiff short spring).
Last edited by davew on Wed Jun 26, 2013 5:53 pm, edited 2 times in total.

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davew
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Postby davew » Wed Jun 26, 2013 5:33 pm

Shock Absorbers / Dampers

Once you have your ride height sorted with suitable springs you can start looking at shock absorbers that match them.

You need dampers to control the springs on rebound and also to assist the springs when you hit a big hole and they are under compression.

Under compression you want a shock absorber that is stiff enough to prevent the spring collapsing too quickly but has enough give to give a reasonable ride, allowing the spring to do it's work in getting the vehicle back up to ride height again.

On rebound the damper needs to prevent the spring expanding too quickly and launching the vehicle into the air. This also serves to prevent the spring over extending on rebound and basically bouncing up and down.

Most cheap shock absorbers are mediocre at both tasks meaning that when you hit something hard, like a deep hole at any speed, the front end will bottom out, transferring all the shock into the occupants and the vehicle and often leading to a dead stop. You can mitigate this to an extent by fitting two cheap shock absorbers on each corner.

On rebound cheap shocks rarely do a decent job and this can lead, particularly on the back end, the vehicle kicking up in the air. On a washboard surface at speed the lack of rebound damping combined with poor compression damping can lead to the vehicle nose diving into the ground and flipping end over end.

I've tried a number of different makes/models of shock absorbers including ProComp, Lovells, OME, Bilstein and Koni. the first three and also Terrafirma) are pretty mediocre at best on both compression and rebound and have to be doubled up to give anything like a decent result.

Bilstein, I know Matthew will disagree with me here :), I find good on rebound but pants on compression because to get decent rebound they are far too stiff on compression giving a really harsh ride - so harsh you sometimes feel like they've been replaced with angle iron !

Koni are the best I've found so far and are now standard fitment on the "White family fleet". The Koni Heavy Track has adjustable rebound and gives a good but controlled compression. They're also reasonably well priced for a good shock absorber. At around £60+VAT each from Paddocks they're pretty hard to beat as IMV they give excellent performance without breaking the bank. The next step up would be Fox or similar but then you'd blow almost your entire budget on one corner !

Koni do a Heavy Track Raid version which is a lot more spendy than the normal Heavy Track and isn't worth the extra unless you're planning on a quick high speed run across the sahara any time soon.

Mounts and lengths for the shock will depend on the spring and suspension arm setup but remember that every time you get a longer travel shock it won't compress as much so needs to be mounted differently to get the extra travel. Sometimes a "standard" length shock will give you all the travel you need if it's correctly mounted.

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davew
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Postby davew » Wed Jun 26, 2013 5:41 pm

Bump stops

Last bit :)

If the kit you eventually put together is well designed and thought out then you can use standard bump stops. If you don't get the shock absorbers mounted correctly though and use extended shock absorbers then you can find the shock absorbers bottom out before the axle hits the bump stop.

Ideally in that case you'd reposition the shock absorber but a compromise that reduces your articulation but saves the shock absorber is to fit extended bump stops.

Remember that bump stops can compress up to about an inch if you land heavily so take that into consideration when measuring everything up.

davidrtaylor
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Postby davidrtaylor » Wed Jun 26, 2013 8:47 pm

Wow.
It sounds simple when explained like that, I never knew or should I say never thought about the order in which to look at how to build up the suspension.

Basically springs, shocks and then accessories.

As for set up now.
Springs.
Ride hight is fine, seems to be higher than most, would like to keep the hight as it is. Reason to change the springs, is they are around 2-3 years old and it had a hard life off roading so they must be ready for changing or braking soon!!!

Shockers.
Seems to drop the axle more than when I first got it and one on front and both on the rear are leaking ie seals have gone.

Reason for dislocation is to get more traction when off road.

So it looks like time to sort it out!!!
Problem I have is I work in London during the week and home at weekends which will soon be changing so I'm home all week, but at the moment I don't have that much time to do much.
So as much help would be great, my lads and I are able to do most jobs our selfs so this could be a easy one for us it's just knowing what to do.

Dave T
Defender 90 tray back 2.5t

Defender 90 bobtail with tray back 2.8 daihatsu.

Shogun V6.

repton
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Postby repton » Thu Jun 27, 2013 3:53 am

davidrtaylor wrote:Ride hight is fine, seems to be higher than most, would like to keep the hight as it is. Reason to change the springs, is they are around 2-3 years old and it had a hard life off roading so they must be ready for changing or braking soon!!!


Someone who has been at it longer than me could well come along and contradict me on this one but in my experience springs don't break with age. Cheap ones sometimes lose their strength and leave your vehicle lower than it should be but I've yet to hear of one breaking.

That said if you're happy with the current height and want to replace them anyway, just try and find out what they currently are and get new ones the same. As Dave said earlier there should be two stripes of coloured paint on them somewhere if they are a standard LR spring which will identify them. You could easily find all 4 corners are different though so do check them all.

Here's a table that lists spring rates:

http://www.landroverclub.net/Club/HTML/ ... rates.html

Going by if you're on"standard 90" springs you should have blue/green and blue/yellow on the front and blue/red and yellow/white on the back. Of course if someone else has already altered things this may not be the case.

Paul

nicks90
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Postby nicks90 » Thu Jun 27, 2013 8:47 am

i would also agree with Paul - springs dont tend to go 'off'. If they are really showing their age then they might have sagged and your ride height will drop. But from what you said, that hasnt happened. So unless you are trying to squeeze enormous tyres under the arches or want to drive a really top heavy truck, leave them alone.

When I went on the hunt for shocks I did a test and then went looking for specs.
I took the springs out and sat my vehicle on its bumpstops and took a physical measurement from the top and bottom mounting points and took off 20mm (bump stop compression) from that measurement. I then went to various places and asked for what shocks had that measurement as a maximum closed length of the shock. That way I knew I was getting a shock that was as long as possible without
a) having to change the shock mounting points
b) not going to over compress and snap them.

I was shocked (get it) to find that the compressed length of several +2" landrover defender shock absorbers varied wildly! Some would have defnitely bottomed out and broken without the use of extended bumpstops, whereas others were only about 15mm longer than the standard shocks I was replacing!
Some retailers refused to give me the specs, others were much more helpful.
I ended up with delphi decarbon +2" and they fitted the bill perfectly, with a compressed length being half an inch less than my measured and adjusted maximum distance.
Also dont go buying relocation cones for the front, you might not need them. Fit the shocks and do a test to see if they pop out.

Nick

ps. welcome to the world of disreputable suppliers, fantastic claims and pure lies - that is 'suspension kits'
:twisted:

pps. there is ALOT of argument about homuch traction a 'dangling' tyre will actually give you. Once the spring has stopped pushing the axle down and it is dangling (eg dislocated spring and the need for relocation cones), they the tyre is only exerting a small amount of downforce - weight of the tyre + bit of the axle in total weight. How much traction and forward force will a tyre give with only 100kg load on it when trying to push a 2 tonne landrover up a muddy cross axle hill? Not a lot.
just something to think about before you heavily invest in flappy - dangly suspension arms etc.
Bugger!
Another bloody dent...

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Matthews
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Postby Matthews » Thu Jun 27, 2013 6:50 pm

I do it my way and it seems to work :shock:

davidrtaylor
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Full Name: David Taylor

Postby davidrtaylor » Thu Jun 27, 2013 7:08 pm

Well I've had a good look and this is what I've found.
Rear shocks are white with black gatters. I think they are ES9000 procomp
Front shocks no paint finish on them so not sure.
Front springs are powder blue. The so called famous Blues I think.
Rear springs are a bit darker in colour. Bearmach I think

Not sure which way to go now!!
The famous Blues have a very good write up.
ES9000 ????? Not sure.

Not easy this!!
Defender 90 tray back 2.5t

Defender 90 bobtail with tray back 2.8 daihatsu.

Shogun V6.

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Bo
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Postby Bo » Mon Jul 01, 2013 5:42 pm

TBH if it works and your happy with it I'd leave be and save your money.
5/4 of people admit that they’re bad with fractions.


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