standard suspension height query

[callum]

I'm trying to deal with my saggy rear springs and don't especially want to lift as i don't really want to get involved with rectifying caster etc.

Easy answer would be some OME low lift springs, but unfortunately there are a few complexities involved which i'm struggling with.

Vehicle in question is a 1991 hdj81 with a factory electric winch at the front end, factory tyre carrier at the back and maybe 50kg's constant load in the back. Tyres are 295's, but i'm not sure that matters. Looking at the parts catalogue, models fitted with a winch got different springs up front, however the bit i'm struggling with is that spring manufacturers, e.g ironman, king, dobinsons state that pre 08/91 80's will get 20mm less lift when changing springs than later models. unfortunately, it is not stated whether this is due to different springs being used before 08/91 or whether the spring perches changed (i've emailed ironman regarding this, but not received any response yet).

At the moment i'm left with a bit of a guessing game with regards to what springs to get. if i get 'stock height' ones i might end up no better than where i am now, on the assumption that the perches are different. If i get more the more common 2" i may end up higher than i want if the original difference was due to a change in spring type in 08/91.

looking at old threads (i think i've now been through just about all of them), it seems they rolled out of the factory with approx 20.5" between hub centre and flare and so should have sagged a bit after 20 years. My measurements below show not really any sag at the front and a fair bit at the back. as a guide, i cant get my fingers between the bump stop (the one inside the spring) and perch at the back, its pretty much rolling on the bump stops.

front:
left - 20.5", 515mm (320mm from bottom to top of spring)
right - 20.9" , 530mm (320mm from bottom to top of spring)

would appreciate any thoughts on how this compares to post 91 trucks or any guesses as to where the 20mm difference alluded to by the spring manufacturers comes from.

If included a few pics, which may or may not be of any help.

thanks

callum

rear

left - 19.5", 495mm (270mm from bottom to top of spring)
right - 19.25", 490mm (270mm from top to bottom of spring)

 

[95LCMachine]

My humble opinion is that your truck would benefit greatly from another inch or two of up travel. I know that they say friends dont let friends run spacers, but a 30mm trim packer from MAF will solve your problems if the OME stock height replacement returns your truck to its curent height.

After reviewing your post again, what is wrong with installing coil spacers in the rear to fix your saggy ass?

I would lean toward new springs and dont muck about with the stock height. Go for the 2.5's and forget it. You will be the only one to notice the lift in a month or two (unless they grow cruiserheads in Scotland like they do in OZ)...

good luck!

 

[joseywales]

i would have to agree with 95 LC and suggest you go with 2.5" springs. You won't need to worry about castor with that size lift. If you are worried about it, the do sell the castor correction bushings with the kits. The OME mediums will sit you about right if you don't want too much height. Most guys run the heavies with a winch, but since yours is factory and not in a big heavy bullbar, meds should be the ticket.

 

[SunTzuMD]

Is it me or is it sitting on the bump stops in the rear?

 

[greentruck]

If those coils are original, they're sagging.

The OME stock height coils will give you at least an extra inch over what you're running now. You'll get a little more in back in most cases. There should be no need to adjust caster, while that is frequently the case with the 2.5" lift. Unless you're looking for lift -- and it doesn't sound like you are -- the OME stock height coils are a good, easy way to go.

Also, if your shocks are still good, no need to replace them either, I did find that the extra weight of the winch was too much for the factory shocks, so I went with the OME Nitrocharger Sports up front.

 

[callum]

Thanks for the input folks. I have also heard back from ironman regarding the 20mm issue. They seem to think it is due to early spring seats being 20mm higher (for clarity, where the spring hits the chassis), so presumably early springs were a bit stiffer to take this up. Ironman actually recommended i go with Toughdog 1" lift springs. Seems a bit odd to recommend your competitor, but there you go. Unfortunately i'd have to import those from Australia, so they're kind of out of the question.

With that in mind, i think i might go with the ironman 2" (50mm) lift. looking at the figures provided on this thread https://forum.ih8mud.com/80-series-tech/436500-ironman-lift.html that should put me not too much higher at the front (a bit less than an inch) and a wee bit over 2" higher at the back.

Other option would be the OME standard heights and spacers, but the springs are almost twice the price and i'm not sure how much the spacers would be on top of that.

Anyway, thanks again for your input, much appreciated.

Callum

Oh its not sitting on the bumpstops at the back in those pics, i've got a whole 1/4" of travel left there. Presumably that's the clonking at passenger in the rear seat was complaining about when i last took a long-ish trip loaded up.

 

[callum]

well i thought i should post up some follow up measurements to make this thread a bit more useful for others.

rightly or wrongly i was supplied with some OME 860 for the rear, which i duly installed and it gave me pretty serious stinkbug look. I was going to send them back as i'd asked for standard height, but i decided to persist and put some mr gasket type spacers on the front which would maybe give about 30-35mm lift once under load.

once they were on, it was sitting to my satisfaction, although the lspv needed shifting in order that a was able to stop the thing at junctions, so i decided to keep them.

anyway i took some measurements tonight, although they are not ideal as it was not sitting totally level.

front
L - 555mm 21.85" R - 550mm 21.65"

rear
L - 580mm 22.8" R - 565mm 22.24"

I did buy a trim packer but i've not installed it yet. Will try and measure on a dead level surface first.

i did take a photo, but i'll post a daylight one as that will be a better comparison.

The recommendation that i wouldn't notice the lift in a few weeks was correct, looks pretty saggy in the picture at the start of the thread. I think i notice it very slightly in the steering, but i'll look into caster correction at such time as i can get the caster measured. It doesn't really bother me, but I like things to drive as they should. With that in mind i intend to chop and extend the roll bar drop links by an inch and a half at some stage too.

Thanks for all your help.