Ironman suspension - Rear Spring Question (1 Viewer)

[CORunner]

Bit of backstory, had a built 100 series that had OME "heavies" 2864s. That 100 got totaled and I pulled most of the parts off.

Got a new stock 100 series and starting to build it up.

Ironman USA is having a sale right now on complete suspension kits (but not on individual components).
Foam Cell Pro 2" Suspension Kit Suited for Toyota 100 Series Land Cruiser/Lexus LX470 - Stage 2

Need some help on rear spring selection. Ironman has 3 options:

	Spring Rate N/mm	Spring Rate lbf/in	GVW adder (lbs)
IM 025B	40	229	0-440
IM 025C	48	274	440-880
IM 025D	70	400	880

Compared to the OME springs

	Spring Rate N/mm	Spring Rate lbf/in	GVW adder (lbs)
OME 2863	44	251
OME 2864	56.0	320
OME 2868	63.1	360

I was happy with the OME 2864s, but it falls between the IM25C and IM25D. My cruiser will be fully built up, but not used for towing.
- Sliders (130lbs)
- Drawers (200lbs)
- Front Slee bumper (134lbs)
- Rear Slee bumper (250lbs)
- Roof Rack (90lbs)
- 2nd battery system (70lbs)
- RTT (150lbs)
- Awning (50lbs)
- Minus 3rd row seats (-90lbs)
So almost pushing 1000lbs of permanently installed gear.

Fully loaded for a trip weight goes up to about 1600lbs (gear, fridge, food, hi-lift, camp kitchen, etc)

Per the IM website I should go with the 025Ds. Did a search on the forum and seems most folks are running 025B or 025C and some complaining that they are too stiff.

Anyone have experience with the 025Ds?

Side question, Ironman also has a stage 3 kit that includes adjustable rear upper trailing arms and lower trailing arms. Worth it? Already plan on getting SPC front UCAs and extended sway bar links.

 

[Frogg420]

Great question. I'm interested to see the replies

 

[abuck99]

Recently I went through a similar process. Upgrading from the IM TOY13B. I considered the IronMan C Spring but it has a lower free height than the 2864 by 25mm or 1". So less spring compression means a little stiffer ride and less up travel before full compression. Offroad I think that translates into a harsh trail ride quality. I think the "D" Spring would be overkill, with a spring around 400lbf/in (70N/mm) the bar diameter is 22mm, I it think it would ride like the rear suspension was mounted on steel beams (unless you were towing an airstream trailer all the time).

I think 2864 or 2868 would be my decision. As for rear adjustable control arms: they will help dial in pinion angle & alignment if your rear height introduces new driveline vibes. I'd wait to see what happens after you have installed your springs.

Here's a cheat sheet I made when looking for springs

 

[CORunner]

Recently I went through a similar process. Upgrading from the IM TOY13B. I considered the IronMan C Spring but it has a lower free height than the 2864 by 25mm or 1". So less spring compression means a little stiffer ride and less up travel before full compression. Offroad I think that translates into a harsh trail ride quality. I think the "D" Spring would be overkill, with a spring around 400lbf/in (70N/mm) the bar diameter is 22mm, I it think it would ride like the rear suspension was mounted on steel beams (unless you were towing an airstream trailer all the time).

I think 2864 or 2868 would be my decision. As for rear adjustable control arms: they will help dial in pinion angle & alignment if your rear height introduces new driveline vibes. I'd wait to see what happens after you have installed your springs.

Here's a cheat sheet I made when looking for springs
View attachment 2494125

Awesome. Thanks for the input. I remember some of your comments on the OME 2863 vs 2864 thread.

Since it is a screaming deal to get the complete Ironman stage 2 kit (20% or $340 off) I think I am going to get it and sell off the IM025B springs and buy the OME 2864 rear springs.

Interestingly enough, the rear control arms are on sale as individual components. So if I need them after the lift, I can get them on sale.

 

[abuck99]

I'd try and negotiate with IM to get the springs backed out of the package and add something else. With either spring choice you'll loose some money selling the springs, since anyone can order new ones and also get free shipping - so you'll have to be lower including shipping or deal with local pick up.

If you have to buy their spring to "get the deal" why not try the C or D spring and see what the result is?

 

[CORunner]

Good point. I'll give them a call to try and back them out.

If I have to sell them, I think I should be able to do a local sale. CO is the heart of Cruiser country!

I can also buy the OME2864 locally from Slee.

 

[abuck99]

One thing you might do ahead of your suspension install is make some notes on your before and after wheel hub to fender lip measurements front & rear, and also ** driveline measurements (this will let you know if you need to adjust the pinion via adj. upper link arms)

At the TC flange measure the degrees up or down ( usually its darn near 90 but might read anywhere from 89~90. Measure your drive shaft slope ( in degrees, down the center line in two or three spots to get good reading), and then measure the output flange degrees ( note direction its pointing up or down).