Chopped FZJ - Spring Rates and Shock valving

[BlueCruiser84]

I've never really looked into matching springs with shocks before since you can just pick up a kit from your friendly dealer, but now I have an oddball that is going to take some figgerin'.

I chopped the back off an fzj80 and bobbed it a couple of inches. It currently has J shocks and stock springs yielding about 4" of lift. The OME L shocks are way to stiff. As are any other fj80 spring.

I'd like to fit a shock that is sort of matched to my stock springs. I've heard that the stock spring rate is anywhere from 150-180 lb/in and I have no idea how much weight I have out back. I have been looking at these Bilstein 5165 Shocks in the 11.3" travel. Optional valving is 170/60, 255/70, 360/80. What do those numbers mean? I know it's compression/rebound but not clear on what the numbers are quantifying?

Basically, I don't want this thing to ride like a Conestoga on the road. Any off-road I do is pretty low speed - no desert racing....

What tips can you guys give me on picking a shock?

Pic for reference. J springs in front and stock springs in rear.

 

[Mace]

Just get a quality rebuildable shock and work on the valving till it works for you. The adjustment is really easier than it sounds.

Or, hit your nearest 4wheel parts and pick up a set of adjustable rancho or pro comp shocks. It'll mostly be compression adjustable, but that's not that big of a deal unless you are going fast off road..

 

[Mace]

And those numbers are compression and rebound valving. Too much compression and you will ride like a brick, too much rebound and the axle can't drop away from the vehicle fast enough..

 

[BlueCruiser84]

Yea I was looking at the bilstein 7100 after I posted that up. I think that's what I'll go with. Unless I decide to cheap out on some adjustable ranchos.

I need to do some More reading on shock valving.

 

[Mace]

Valving is just varying the rate you allow oil to bypass the piston in a shock (simplified but).
Here are some great articles to read up on.
Off-Road Shock Tuning Guide | How To Tune and Valve Off-Road Racing Shocks
www.crawlpedia.com/shock_valving.htm

 

[BlueCruiser84]

OK. Did some reading. Bilstein 7100 Short Bodies would be the winner if not for the upper and lower heims. It seems that there should be an option out there to run bushings in place of the heims... anyone have any hints? Also looking at the 5165s to get the bushings.

 

[BlueCruiser84]

From a Discovery site. Maybe this is the ticket.

You can order them from several online retailers including eShocks which is where RTE orders their 7100s from (Summit Racing also carries them)

Call eShocks: (800) 303-6211
Talk to: Paul - Bilstein rep
Ask for Prothane 19-920 - Bilstein 7100 heim joint replacement bushings
You need 4 packages as each package comes with 2 bushings (top and bottom).
Total will be around $45

Craig