[2015 Z Force 800 53/Trail EPS]

Ok, as best as I can measure it, the stock springs have an inside diameter of 2 3/16" which is 58.82mm. That makes the new one a hair larger at 2 3/8" or 60.45mm. Not much difference.

The changes you made to that rear sway bar has probably had some effect to rear spring rate. Have you had a chance for a good test ride?

That Bandit shock package looks comparable to Elka Stage 3 package. It would really be nice if a simple spring change would make a significant ride quality improvement.

[2015 Z Force 800 53/Trail EPS]

The changes you made to that rear sway bar has probably had some effect to rear spring rate. Have you had a chance for a good test ride?

That Bandit shock package looks comparable to Elka Stage 3 package. It would really be nice if a simple spring change would make a significant ride quality improvement.

Not yet other then around the yard here. Have a week-long camping trip planed for the 23rd-28th then another one next month though. In all honesty though, if I am going to spend over a grand on shocks, I'll spend the extra on Elka. I think even Elka Stage 1s are at or less then Bandit's low-end shocks. I just want these springs to get me by until I can justify.. either cost.

In the first pic it looks like the shock is almost touching the bump stop is that how it was before or where u compressing it to show the travel?

[2015 Z Force 800 53/Trail EPS]

In the first pic it looks like the shock is almost touching the bump stop is that how it was before or where u compressing it to show the travel?

It was actually a bit farther then it looks.. also the pics was taken before the final preload adjustment . It only took another 5mm of preload to gain another inch of rear height. I'll take a few more today at better angles..and as it has no extra weight on it now. 

[2015 Z Force 800 53/Trail EPS]

Some new pics with the final preload set. Man I need to get to that back side with the pressure washer better...lol

When I jump on my receiver (190lbs), the rear hardly moves (read: very stiff suspension).
I've always assumed that this was due to spring force was too high for the weight that is on it.

Have you noticed any difference in compression/rebound with the new springs when jumping on the back end?

[2015 Z Force 800 53/Trail EPS]

When I jump on my receiver (190lbs), the rear hardly moves (read: very stiff suspension).
I've always assumed that this was due to spring force was too high for the weight that is on it.

Have you noticed any difference in compression/rebound with the new springs when jumping on the back end?

For mine all that ended when I got rid of the soft yellow a-arm bushings. Even greased they never slid over the sleeve surface like a bearing..like the new hard delron's do. And dry they almost locked in place. It now moves fluidly up and down when on the hitch and always returns close to the same position..ie I don't have to pick it up to bring it back or it doesn't hold-down like it's sagging. With the new springs I actually have them set a little stiffer to start.. knowing they may settle-in some and..I wanted a bit more ride height then it had before with the old springs anyway but with the old springs I was afraid of running out of spring as fast as they were collapsing so I didn't give it any more then what was necessary to maintain the ride height it had. Really looking forward to some rough trail riding now just to see if it made the difference I think it will. Flicking it around the yard and street here it feels really good. 

[2015 Z Force 800 53/Trail EPS]

Well, I am delighted to say they did improve the rear's ride noticeably. In fact even my wife..who never notices anything said she could feel a big difference. Said now if only the front felt as good I would have it made.

Good news 

Well, I am delighted to say they did improve the rear's ride noticeably.

Can you elaborate on the nature of the improvement?

Would you recommend the spring replacement to others as an interim step to replacing the shocks after they fail?

I have an itchy trigger finger on this subject ;-)

[2015 Z Force 800 53/Trail EPS]

Well, I am delighted to say they did improve the rear's ride noticeably.

Can you elaborate on the nature of the improvement?

Would you recommend the spring replacement to others as an interim step to replacing the shocks after they fail?

I have an itchy trigger finger on this subject ;-)

As I am working with Bandit now to get something for the front, I had a working theory that has even more evidence to support that theory. Because it was the lighter coils that were loosing distance between the coils and as time went on it took less and less suspension movement to feel that "bump" that most would think was the shock bottoming-out, I surmised that what was actually happening was the lighter coils were coil-binding and as they ended their travel and came to the heavier coil it was such a difference it felt like the travel had ended. This though was supported when I saw all the paint warn off between the softer coils on both front and back and no sign of coil contact on the heavier coils...and no dirt knocked off the end of the rubber stop. With the new single rate springs there is no coil binding, only progressive rate increase as it compresses. I tried like hell to get the rears to bottom out and could not. In a perfect world of dual-rate springs, I think as the softer coils reach say 80% of their compression, the heavier rated spring should already start to be in motion blending the two. Elka does this with their dual spring-dual rate setup. CFM's attempt using a single spring makes it feel like it hits a "wall" when it gets to the heavier spring. Probably why the new ones went back to a single-rate spring.

As for the improvement...it was like the back was floating over the roughest of rocks on a suspension that for once.. actually worked- where the front was still hitting that "wall" on every rock even with the compression set wide open. I think the key here is get rid of the CFM dual rate springs and just use a single rate spring. Having a little trouble getting one from Bandit that measures the same as the CFM spring...and it can not be any longer. The CFM spring is 11 1/16"s long which is an odd size ( go figure) as they commonly come in 8,10,12 & 14 with the 40mm end IDs. Can't do the 12s bit maybe the 10s as I have a lot of preload adjustment I can use.

Do you think the medium spring rate is sufficient?

I'm just wondering if it would be reasonable to consider the heavier spring rate (given that the Z Trail is 240lbs heavier than the Wildcat Trail) or to stick with the mediums.

I'm more likely to pull the trigger now rather than wait for something Z specific to be developed.

[2015 Z Force 800 53/Trail EPS]

Do you think the medium spring rate is sufficient?

I'm just wondering if it would be reasonable to consider the heavier spring rate (given that the Z Trail is 240lbs heavier than the Wildcat Trail) or to stick with the mediums.

I'm more likely to pull the trigger now rather than wait for something Z specific to be developed.

Their medium set for the Wildcat Trail is 200lbs rears and 175lb fronts. Going by that the 200lb rears were perfect I am going to assume the 175lbs fronts are what we will want for the front...but..their 12s are too long and they are telling me they thing their 10s may be too short. I just told them that we have over 3"s or preload adjustment and aren't using much of that at all so an extra inch or so wouldn't be a problem. I also told them if they do work..get ready for some orders from the CFM world. Hold on and let me be the guinea pig. The Wildcat Trail's rears will work on our trails..that's confirmed. 

Re: the travel. I made a more careful measure of my shocks day before yesterday when mounting my new 27" Wanda tires. The stock CF Moto shocks, off the machine and fully extended, show in the front shocks exactly two (2) inches of ram travel until the bump stop. The rear stock shocks show 2 3/8" of ram travel from fully extended up to the bump stop.
Changes to preload/ride height must be accomplished within that narrow range and yet leave enough travel in both compression and extension to make the best of it.
The front Elka shock ram provides 3 1/2" travel to the bump stop and in rear, 3" from fully extended to the bump stop.

In my case with the rider and cargo weights I submitted, Elka fitted both my front and rear shocks with the same springs (!) F 04 - 254 (uncompressed length in millimeters)
I believe that's a 200 Lb spring. They accommodated the heavier back end of the ORV by preloading the springs on the rear shocks almost an inch more than the front ones.
(I find it amusing that as someone said, Elka doesn't recommend adjusting the collar down more than 3-4 turns and after that they suggest you buy a stronger spring, and yet they themselves will preload the same strength spring THAT much (nearly an inch) to make it work on the rear)

Anyway their magic works, and the machine handles the lumps and bumps much more nicely than it did. As set up my rear collars are at the bottom end of the threads supplied (it was a scant 3 turns to get there) and the fronts set so that with the 27" tires I have 9.5" G/C in the rear and 9.5" G/C to that oddly low spot at the rear of the front bash plate. And I hardly bashed it at all in 150 Km of 2 man riding yesterday.  Much better.

ps: In my case with stock shocks on and me jumping on the rear receiver the back end hardly moved at all, and yet with the Elkas jumped on I feel it responded as it should, compressing and releasing. When I get off and lift it by hand the machine settles back to the same spot it left and no squeaking or resistance is detected. A carpenters tape that I stood on the concrete with the end extended to touch the skid plate and some drag applied with the thumb brake so it will push in and hold the reading, showed it had compressed at least an inch and a half before returning. Delrin will be slippery-er for sure but I don't think I'm being limited by the stock bushings... yet.