2 Thumbs Up on 48 CC Zokes!

[Bandit9]

Just wanted to say that I'm impressed with the 48mm CC Zokes. My tuner did a good job. They feel just as good as the KYB SSS forks that were on my YZ250. Which I didn't think was going to be possible, but the performance in the dirt don't lie. I can pretty much hit anything from roots to whoops to jumps to G outs and they suck it all up with no fuss. It is going to get better too, I still have haven't played with the PFP and I'm still fine tuning it.

 

[AZRickD]

Funny you should mention the PFP. I googled info on adjusting with it and I am as yet not quite sure what it does and when to use it.

As far as the 48mm Zokes go , the biggest plus is its ability to soak up big hits ( either G-outs or jumps). In stock form both the fork an 888 Ohlins shock are too stiff and very lacking in rebound. The forks required two shims worth of bleed to soften them and about the same in the rebound stack.

 

[Jakobi]

2 shims worth is a bit vague

I'm still working on breaking mine in. They were pretty stiff out of the box, but don't feel all that bad after a few minutes. I imagine they'll get better.

From what I understand the PFP is like changing the ICS in a set of KYB/Showas. (The internal spring). Or increasing the pressure on a WP Bladder fork.

Less preload can plushen up the initial action of the fork, while cranking it down will firm it right up. I don't imagine it will be something that I use too much. More likely I'll set it towards the midde and then work on the stacks.

 

[desertgasser300]

Funny you should mention the PFP. I googled info on adjusting with it and I am as yet not quite sure what it does and when to use it.

As far as the 48mm Zokes go , the biggest plus is its ability to soak up big hits ( either G-outs or jumps). In stock form both the fork an 888 Ohlins shock are too stiff and very lacking in rebound. The forks required two shims worth of bleed to soften them and about the same in the rebound stack.

The PFP is basically an external pre-load adjuster.

 

[Jakobi]

http://shimrestackor.com/Code/Sample_Applications/Midvalve_ICS/ics-perf.htm

 

[Simmo737]

The PFP is basically an external pre-load adjuster.

I agree. It increases the amount of hydraulic pressure that has to be overcome prior to the damper rod moving in the cartridge, it's preload.

The cool thing about it is that the ramp from preloaded to movement can theoretically be controlled by shim stacks, and then you can vary the ramp with a change in pfp preload, it's much more complicated than a simple spring preload variation, but appears the same. I think that it adds almost too much variability, bit like the shim controlled bottoming valve and needle variable pds style valving in 4cs forks, tuners are struggling to unlock the more tunable aspects of both systems, but it all holds a lot of promise. All IMHO

 

[Jakobi]

Agree Simmo. Its the pressure on the inner cartridge, or if you think of it like a shock its similar to varying the N2 pressure. A big consideration is that if running not much PFP and relatively stiff stacks it may cause cavitation in the chamber. I think for me personally, I'll be simply trying to tune the stacks to work, and then using as little PFP as required.

 

[AZRickD]

What behaviors would I use tha PFP to tune ?

 

[twowheels]

Agree Simmo. Its the pressure on the inner cartridge, or if you think of it like a shock its similar to varying the N2 pressure. A big consideration is that if running not much PFP and relatively stiff stacks it may cause cavitation in the chamber. I think for me personally, I'll be simply trying to tune the stacks to work, and then using as little PFP as required.

It's worthwhile running a lighter rate or shorter PFP spring as well. That makes the adjuster effective up and down.

PlusOnePerformance

 

[noobi]

What behaviors would I use tha PFP to tune ?

If im understanding correctly, the initial travel of the fork.
Assuming all things being equal, more preload on the PFP gives a firmer initial stroke, and less gives a softer one.
Its more complex than just that, as it is affected by valving as the others have said.
Say you were riding in the bush early in the day, then after lunch went to a faster, jumpy sort of track, you would probably give a turn in on the PFP to accommodate the faster riding later.
This is all relative, and some guys ride mx fast in the bush, but the bush/mx example is one that was often used to describe where you would use it.

The advantage, I think, is that you can have plusher valving for slower terrain, but then when you get to a faster track, you could crank up the PFP and you wont be beaten up so badly. It makes the fork more versatile before needing to be re valved.

 

[AZRickD]

And how would that make the initial stroke change compared to adjusting the compression clickers ?

 

[Jakobi]

Great thinking Steve. I haven't had mine apart yet to see how its all assembled. Something that will happen more likely sooner than later.

The more preload on the ICS the higher the pressure of the internal chamber will be during an impact. Higher pressures = greater resistance to both initially moving, and through the valving. Increasing it may be similar to going up a spring rate.

The compression adjuster is just a bleed on the stack. It can only bypass a set volume of fluid at any one time. Closing the comp adjuster up can increase the damping, but more so low speed damping. The PFP should have a more noticable/greater effect on feel, without changing the actual damping curve as much. Just making it firmer over all.

If you want a quick demo, take a shock and remove the spring. Put 150psi into it and then adjust the compression clicker and cycle it through its stroke and see if you feel the difference. Then drop 50 psi out and do the same, then drop another 50psi. See if you can pick the difference.

 

[AZRickD]

Hmmmm. Given that, I think I will try backing off the PFP one notch and upping the compression clickers a half turn or two (they don't click, btw).

 

[Simmo737]

I was laying in bed last night with a Christmas level of red wine on board thinking about pfp adjustment and why gasgas valving has no float on the mid valve. I think the pfp is a great tuning kit for getting a wide range of stock settings working. I have been avoiding preload on this bike and have changed my thoughts, I have .48 springs, I had been running zero pfp, 2 mm preload and clickers c10 r 11, I had never gone the other way. I think no float means the stack s operational at anything more than zero movement and the pfp pretty well determines how divey you want the bike. I wound in 2 pfp and went in to 9r and went out to 18c and I had the same amount of brake dive and was using a lot more stroke on square edges and the bike is a lot less spikey, I went in to 2.5 and the dive reduced, bit more follow the ground feel but not obtrusive and the same lush highspeed feel, this all just around my 2.5 acre block and dirt roads so I would need a days ride to really fiddle and verify but I think it proves that the pfp is better than just a spring preload as you maintain the valving characteristics. Maybe gg or zoke no what they are doing with that mv.

 

[Simmo737]

Also am I right in saying that once you've overcome the preload the spring rate Increases at the standard rate, 1.5 kg/mm or whatever so it actually is only a higher cartridge pressure until the spring is moving from a point where it would be at the same preloaded or unpreloaded. This is the value of a spring vs gas pressure.

My brain hurts.

 

[twowheels]

Also am I right in saying that once you've overcome the preload the spring rate Increases at the standard rate, 1.5 kg/mm or whatever so it actually is only a higher cartridge pressure until the spring is moving from a point where it would be at the same preloaded or unpreloaded. This is the value of a spring vs gas pressure.

My brain hurts.

Convert the preload to a pressure needed to deflect. You can always resolve to a force or pressure since you know (presumably) the piston area.

PlusOnePerformance

 

[AZRickD]

Seeeemo, your Post # 14 is what I hope to see. Compliant with less smooshy dive and more stroke without losing the 48mm Zoke's excellent G-out control.

 

[Simmo737]

Convert the preload to a pressure needed to deflect. You can aleays resolve to a force or pressure since you know (presumably) the piston area.

PlusOnePerformance

Yep, so once the deflection occurs the spring rate is the is the same for the compressed distance of the spring regardless of preload as the preload has been overcome, with gas pressure, the rate is progressive due to the compressibility of gas just like oil height in the legs. So by not having a float, you are hoping to have enough pressure to back fill with the spring preload static pressure, and with gas the same, where as kyb/ Showa are lower/zero static and therefore need a float to backfill quickly on rod movement due to the very fast ramp in pressure due to the spring loading up, hence why main spring preload is around 10mm stock on jap bikes and 5mm on the zokes. Brain exploded.

 

[Jakobi]

I think my minds going to be turning over night.. To be honest I haven't even checked the PFP on mine yet; no idea where its at stock. Clickers initially set at C14, R10. Doesn't feel too bad but likewise, won't know until I clock up a decent ride.

 

[twowheels]

You can think of the PFP as simply an additional spring aiding in the support of the front end of the bike. It's adjustment allows for easy external adjustment of front end stiffness. That's one of the reasons a 48 Marzocchi PFP fork with 0.42s feels way stiffer than an 48 Sachs OC or 45 Marzocchi OC.