Thread: D2 suspension upgrades for noobs...

You've clearly done a lot of reading and research on this, but all of the information you have combines a number of setups that wont necessarily work together. It is mixing a big lift high flex setup with a heavy touring setup and they don't necessarily work together and it will cost a lot of money.

Front springs, you will need at least 220lb/in spring rate if you're running a bullbar and especially if it has a winch in it. Lower than that and the springs are not able to sustain ride height, then a year down the track you're replacing front springs.

Rear springs, 270lb linear is soft and you can run them with Polyairs when loaded or 300-340lb/in progressive rears. Don't be under the impression these rates don't flex, they will. I wont go into the whole linear vs progressive as thats an article in itself, especially with the progressives.

Dobinsons have a great name and product, but they're not so different to any other Australian spring manufacturers. They really made their name about 20 years ago in the custom 4WD world because they were more than happy to make custom springs. I'm just saying, they're good but don't lock yourself in to one brand.

Shocks, if you're touring I would recommend something like Bilstein that have the oil seperated from the pressurising gas as they dont fade as they heat up. Remote canisters also if you want Gucci as the concept is the same but they're not necessary unless you need it for packaging the suspension travel setup - ie for a given open length they have a shorter closed length. Twin shell, nitro etc shocks, doesn't matter who makes them, they all have the same problems by design when touring, the gas and oil mix when they get hot and they fade until they cool off. Foam cell, I don't think are suitable for touring irrespective of make or size.

For shock length, 12" is extremely long and I would argue far too long for 2" springs. Actually 2" springs are not that much different in free length compared to standard springs. For 4" lift springs most people are running 10" or 12" short body shocks at a stretch. 12" shocks will probably give you suspension travel but they're not the limiting factor in producing articulation which is probably what you're after - you would need to either have ACE or run disconnects on the swaybars (not both!). I'm not a believer in dislocating spring and the regs require springs to be retained by the original method, but also with the Disco2 suspension design, the links inherently produce a lot of roll stiffness which doen't make dislocation all that beneficial anyway, its a different setup to the rears on Rangie Classics, Disco1s, Defenders etc where it works well. When LR changed to the radius arm rear suspension on the D2 it balanced the rear to work with the front already as the roll stiffnesses are far closer that what the others have.

Shock turret heights, you will need to compare shock closed lengths to gain that measurement.

Seriously, 2" lift is just springs and shocks and nothing else. If you setup well and max those springs right out, then add to that a Xmember spacer, rear ABS extensions and brake line extensions. Nothing else on that list is needed.

Tyres: That setup will run up to 265/75-16 max on standard rims without rubbing.

Originally Posted by Slunnie

You've clearly done a lot of reading and research on this, but all of the information you have combines a number of setups that wont necessarily work together. It is mixing a big lift high flex setup with a heavy touring setup and they don't necessarily work together and it will cost a lot of money.

Front springs, you will need at least 220lb/in spring rate if you're running a bullbar and especially if it has a winch in it. Lower than that and the springs are not able to sustain ride height, then a year down the track you're replacing front springs.

Rear springs, 270lb linear is soft and you can run them with Polyairs when loaded or 300-340lb/in progressive rears. Don't be under the impression these rates don't flex, they will. I wont go into the whole linear vs progressive as thats an article in itself, especially with the progressives.

Dobinsons have a great name and product, but they're not so different to any other Australian spring manufacturers. They really made their name about 20 years ago in the custom 4WD world because they were more than happy to make custom springs. I'm just saying, they're good but don't lock yourself in to one brand.

Shocks, if you're touring I would recommend something like Bilstein that have the oil seperated from the pressurising gas as they dont fade as they heat up. Remote canisters also if you want Gucci as the concept is the same but they're not necessary unless you need it for packaging the suspension travel setup - ie for a given open length they have a shorter closed length. Twin shell, nitro etc shocks, doesn't matter who makes them, they all have the same problems by design when touring, the gas and oil mix when they get hot and they fade until they cool off. Foam cell, I don't think are suitable for touring irrespective of make or size.

For shock length, 12" is extremely long and I would argue far too long for 2" springs. Actually 2" springs are not that much different in free length compared to standard springs. For 4" lift springs most people are running 10" or 12" short body shocks at a stretch. 12" shocks will probably give you suspension travel but they're not the limiting factor in producing articulation which is probably what you're after - you would need to either have ACE or run disconnects on the swaybars (not both!). I'm not a believer in dislocating spring and the regs require springs to be retained by the original method, but also with the Disco2 suspension design, the links inherently produce a lot of roll stiffness which doen't make dislocation all that beneficial anyway, its a different setup to the rears on Rangie Classics, Disco1s, Defenders etc where it works well. When LR changed to the radius arm rear suspension on the D2 it balanced the rear to work with the front already as the roll stiffnesses are far closer that what the others have.

Shock turret heights, you will need to compare shock closed lengths to gain that measurement.

Seriously, 2" lift is just springs and shocks and nothing else. If you setup well and max those springs right out, then add to that a Xmember spacer, rear ABS extensions and brake line extensions. Nothing else on that list is needed.

Tyres: That setup will run up to 265/75-16 max on standard rims without rubbing.

Ok, so this answer (cheers) has raised quite a few more questions...

My goal is to upgrade the sus in such a way that I have maximum options (touring and flex/tuck) in the future with practical costing.

Re. Springs, I will roll with your suggestions (linear +220lb front and progressive +300lb rears seem to fit) and see what I can find in the oz suppliers range.

I think I will still go with the pin mount fronts as the eye mount (from my research) is the limiting factor in flex there - not sure what spring lift these lads have but they are maxing the 12” out in the front, and bush bind is the limiting factor... the pin-mount upgrade seems easy enough... also I think turrets might be adjustable??

I did not realise the remote res shocks decreased the body size but kept the “extended” length. That would help with the rear as changing and raising the upper mounts looks complicated. On that note... when looking at an “un-named” shock website for eg. They say rem’ res’ shocks HELP with touring and gas/oil fade - I take it you’re saying it’s marketing ****??

Do you have supplier suggestions for retaining kits and front swaybar disconnects? Cheers

Originally Posted by Slunnie

Seriously, 2" lift is just springs and shocks and nothing else. If you setup well and max those springs right out, then add to that a Xmember spacer, rear ABS extensions and brake line extensions. Nothing else on that list is needed.

Does this mean I can buy longer springs and shocks and have a 2" lift?

Originally Posted by jezzarezza

Ok, so this answer (cheers) has raised quite a few more questions...

My goal is to upgrade the sus in such a way that I have maximum options (touring and flex/tuck) in the future with practical costing.

Re. Springs, I will roll with your suggestions (linear +220lb front and progressive +300lb rears seem to fit) and see what I can find in the oz suppliers range.

I think I will still go with the pin mount fronts as the eye mount (from my research) is the limiting factor in flex there - not sure what spring lift these lads have but they are maxing the 12” out in the front, and bush bind is the limiting factor... the pin-mount upgrade seems easy enough... also I think turrets might be adjustable??

I did not realise the remote res shocks decreased the body size but kept the “extended” length. That would help with the rear as changing and raising the upper mounts looks complicated. On that note... when looking at an “un-named” shock website for eg. They say rem’ res’ shocks HELP with touring and gas/oil fade - I take it you’re saying it’s marketing w^nk??

Do you have supplier suggestions for retaining kits and front swaybar disconnects? Cheers

I can absolutely assure you the shock bush isn't limiting travel. Never the less if you are bent on changing mounts, I'm pretty sure the RRC/D1/Def front turrents will bolt on.

This site will show you the differences between standard, remote res and short body remote res lengths and travels.
Bilstein 7100 series | Marlin Crawler, Inc.

Saying remote res helps with fad isn't marketing ****, it is legit. The difference between a monotube like Bilstein and a remote res shock is that the gas charge and seperating piston is in the bottom of a regular Bilstein or it is relocated into the remote res for that type of shock. If you remove the gas charge and seperating piston from the bottom of the shock it allows more travel of the actual shock piston and it will be able to cool a little better. Both are not so different, but they are a good step ahead of regular twin shell nitro/oil shocks for touring and miles ahead of Foam cell shocks.

No supplier recommendations for retaining kits.
For disconnects, when this was being developed, people were using Jeep disconnects, but there may possibly be better options these days.

Something to consider - especially as you want touring as well.

Mega flex doesn’t equal traction - at full flex there is often very little weight on the wheel and therefore no traction.

Moderate flex and a Locker or ATB will get you a heck of a lot further and do it easier.

I run on my d2a custom dobinson 3inch springs, with Bilstein 7100s and extended brake lines, bump stops, watts linkage, cross member, adjustable panhard rod, and Setup up the shocks and springs for touring, best combo I have found, plus I run F&R lockers so traction is good

Originally Posted by Bohica

Does this mean I can buy longer springs and shocks and have a 2" lift?

Sorry Bohica, I missed this.

Yes, the length of the spring depends on the spring rate, so a softer spring is longer than a stiffer spring. Just about all 2" lifts also increase the spring rate to retain control over the vehicle and to add to load carry capacity, but because it is a stiffer spring it will also compress less under the vehicle weight so the ride height comes up. The target ride height is then achieved by altering the springs free length. So if you want to retain a 2" lift but want a longer spring the spring rate has to be reduced.

But then there are progressive rate springs....

These are dual rate springs. They have an initial spring rate, a transition point, and a second spring rate. No doubt some now can change their rates progressively with tapered wire and winds, but thats another story. Progressive springs can be set up in a couple of ways. In my 4WD I've set them up so they run at 300lb/in for comfort and after 1" of compression the rate increases to 340lb/in. This is to give comfort and then the rate increases for load carrying capacity. The other way I had setup in another non-LR 4WD (This was an off the shelf TJM spring) was that it sat statically in the secondary spring rate, but the initial spring rate was set really soft purely to increase the spring free length for additional travel.

For the shocks, you can compare spring free lengths and then roughly increase shock length by the difference in spring free length... roughly, but I know you want more than that. If you're patient, install the new springs, these are retained by being held captive and the shock length is what keeps it captive... but captive by how much isn't specified by the modifications rules so you can reduce that amount, the spring only needs to be just held in and from the factory they are held in by quite a fair bit. Put the spring in, bring the axle up to make the spring lightly captive, take the shock measurement from the shock bolts and go from there. Shock length measurements are from the centre of of the bolt diameters but its easier to measure to the bolt and then calculate for the diameter. To be honest I think its a good thing to only lightly hold the spring captive because it loads the shock less at full travel with less impact... and you get more suspension travel!

Originally Posted by Tombie

Something to consider - especially as you want touring as well.

Mega flex doesn’t equal traction - at full flex there is often very little weight on the wheel and therefore no traction.

Moderate flex and a Locker or ATB will get you a heck of a lot further and do it easier.

I went to school with one of the guys who does domestic 4WD racing (Outback Challenge etc), owns a number of 4WD shops etc. He says the same, bring it back off the big flex and drive it on the lockers.