I have a U.S. z8ex, not the elka shocks.  I was wondering what everyone had their pre loads set to. The settings on mine were messed up from day one. The passenger side was set full fast, the drivers set full slow. I have those settings tuned well now but I was getting a lot of tail buck when I hit jumps. The front pre load had about 1/4 in thread showing from the top of the lock ring. I set them so there was about an inch of thread showing and now have much more level flight when jumping. Of course the ride is stiffer but not bad. I understand pre load varies by terrain and load. I weigh 190 and the wife is 110. We run a lot of mountain trails. Just trying to get a better idea. Thanks!

[2015 Z Force 800 53/Trail EPS]

Sense no one else has chimed in yet I'll throw in what I know.

Spring preload is set primarily for two reasons however is subjective to the needs of the rider and all preload measurements are supposed to be done with all the normal load the vehicle will be carrying which includes passengers and all normal gear.

1.  To set the ride height. The correct ride height is actually to position the suspension somewhere in the center of it's travel from top to bottom of it's travel with the shocks installed. This is the correct position for the best all around performance of suspension however many opt for more ground  clearance by increasing preload which not only stiffens the suspension but also moves the operating zone to a lower position which adds increased angle to the CV joints and limits downward travel.

2.  To set the "Attack Angle" or caster angle of the suspension. This is a measurement from the front to the back of the machine. There is a simple fact that the more positive the caster angle suspension has, the better the suspension will work . However, if you follow some manufacturer's instructions, their best angle actually puts the front higher then the back. Elka is one that wants to set the front slightly higher then the rear. This is best for competition applications but not best for the average trail rider. For "us", having the front and back level or even having the front between 1/4-1/2" lower is best especially in snow or sandy situations. For the Z with it's flat skid it just a matter of taking a measurement as close to the center and between the wheels front and back.

It is incredibly important that both fronts and both backs are set exactly the same. Even a 1/4 turn difference will have an effect on it. I suggest using a decent caliper and measuring from the top of the adjuster ring to a fixed point on the shock body above that. The only reason not to would be because of a spring weakness or to balance a load.

In setting up the suspension the preload settings are always done first. Then the compression settings, then lastly the rebound settings.

Thanks for response. I first started looking at preload when I  was getting bad tail buck when jumping. It was dangerous, then while looking at the machine i noticed the front sat lower than the back. I looked at a bunch of pictures online and saw the same thing. Mine was low. After I added the preload, it leveled out considerable. Additionally now when I jump I get nice level flight. I'll do another test run to adjust the other settings. I know that it all depends on the machine, riding terrain, and load. We ride many mountain trails, lots of rocks, ruts with a mix of high speed runs and slow crawls. After reading your post I mea sure front and rear preload and I'm just a fraction of an inch more preload in the front. In the rear I still have the 2 spring setup. This is good info. I see a few more adjustments in the future. Thank you

[2015 Z Force 800 53/Trail EPS]

Welcome.

Setting preload to your riding style is also a reason to adjust.  I for one like to ride low and let the skid plates do their job and slide over the junk.  We dont have many rocks and I dont play in the  mud so really its just dirt and roots that i would be sliding over anyway.  Having a low slung suspension lets me run softer preload on the springs.  This also allows more droop for me which lets me soak up bumps better.  I also like to run a fast compression and a slower rebound (think of trophy truck suspension that squats and likes to stay down low more.  I am almost always riding alone and with an empty bed also.  Now this setting of suspension usually makes for longer and lower flights off of jumps also as the slow rebound and softer spring settings dont want to let it push up off the jumps real hard.  But I'm ok with that.  I dont plan on investing to much time into messing with the stock shocks (same ones you have) as they just dont ride as good as aftermarket offerings that are out there.  I plan on going with some Elka's (stage 3 or stage 5) next year at some point because IMO you cant beat the ride that those produce and the stock shock while they look nice just dont have the ride quality that I was hoping they would.

I think the issue I was having was the front was too soft and the rear was too stiff. By matching them up better I found it pushes off the jumps and large amount of whoopties we have on our trails out here. The ride is stiffer but it feels more evened out as a whole. I would like to invest in the elkas for sure. Unfortunately my test run got cut short by a puncture in my front tire (stock abuzz are junk 2 ply) so I'm down until I can the tire to a local shop that can vulcanize the tire then it's new rubber before I can do shocks.