Stock shim stacks for the Marzocchi Shiver 48 on 4Ts

[GMP]

Thanks Leon. There are no local winter races here anyway, it would be for trailriding, but the trails are on the rough side. Next seies north of me has one winter race, if there is enough snow, as not to damage the trail.

[GMP]

Got my upper tubes back from Racetech today. Have to say I'm quite impressed with the work. Very nice, inner surfaces look like black chrome. Much smoother than a previous job I had done to a set of 45mm tubes by another plating shop. I'm sure it was honed/polished after anodizing. Everything went together fine and stiction seems normal for all new parts. While I was waiting, went the extra mile and polished the springs outer surface, along with the bores of the lowers. Just fitting the parts you can tell quite a difference in friction, should help keep the oil cleaner as well. Finished them off with some valving tweaks. Only a ride will tell for sure but looking a lot better than when broken down a month ago.

[Leon_RR250]

Good to see you are happy with the new anodizing. Waiting to hear about how your new valving feels..!

Leon

[Leon_RR250]

Hi!

I had another practice yesterday. I analysed more what Glenn wrote about the functioning of the PFP and I concluded that it affects a lot more the high speed damping than the low speed. So yesterday I started with half turn out on the PFP (now 1.5 turns in) and plus 4 clicks on the compression. I left it there for the whole practice since it felt better, more compliant, through the rocks and roots without being too soft through the whoops or generally on higher speeds. I will have a longer practice in the same forest tomorrow and I will come back with more feedback. Definitely the PFP is NOT simply working like air spring/adjustment of oil level as others believe. Thank you Glenn for your analysis on the dynamics, etc, earlier..!

Leon

[GMP]

Glad your figuring things out. I was incorrect in stating the PFP preload change earlier off hand in this thread, it is .5mm per turn of the adjuster after measuring. VERY delicate threads in the cap ID/collar. The PFP is a bit limited in its usefullness, due to the high starting preload. I have never raced with more than 2 turns, and in rocks from 0 - 1 turn. For now I have left the base valve bleed stock, added a 26 x .1 over the last 32 x .15, and removed all the bleed from the rebound and mid. In case the fork with all the new bushings and coating is sticky at first, I did not want to aggrevate the situation on the trail trash. I plan on doing an early first service to check the oil condition and can stiffen it then. Likely though, the first race in 3 weeks will also be the first ride on the fork, as there is now about a foot of snow with a half inch of ice on that covering the ground here. Course is pine woods/some whoops/MX, mostly sandy trail, some roots but not to bad if the fork is a little stiff. Better than possibly deflecting off rocks in a high speed section of a mountain course.

Yeah, the guy going around the forums telling everyone that PFP is the same as changing outer oil level has no clue what he is talking about. Its like holding up a glass of a clear liquid and saying "Yes, must be water".

[Leon_RR250]

Hi!

We have got a really strange winter without snow generally until now. The national race for this Saturday is cancelled as is a national race 2 weeks later. Next week they promised to do a national race whatever the weather and conditions and I am going there because I do better and I like better really technical conditions. No practice in the dark now but a club race on Saturday is scheduled.

I will go even stiffer for the clicks (12 out from 16 out now) and open half more turn the PFP, to be 1 turn in, to test this Saturday, since it was so much better during the previous two practices. I want to keep even more higher the fork in the stroke and add compliance for the fast and hard/sharp hits. I think I can arrive to a point with this fork when the same clicker and PFP settings will work in sand and in the slower rock gardens, even if I will have to revalve the comp stack one more time. The additional functionality of the PFP makes this possible. The more I think about the ideas implemented in this fork the more I like it...

Leon

[Leon_RR250]

Hi!

It was good somehow that the national race was cancelled and instead I tried the club race because the fork is not ready for rocky paths with embedded sharp stones/rocks (and many of them hidden....). Nine tests, 1 hour 6 min total test time for me and only maybe the six minutes where on ground without stones. It was the first time to try an unknown technical trail for me with this bike and fork set-up and it was more or less punishing...

I started with 12 clicks out and 1 turn it for the PFP. The first round with 3 tests were done with this setting and the hands were half pumped for tests 2 and 3. Second round and I decided to open 3 cliks the comp to 15 out. Hands were ok then but then the fork got much harsher everywhere. I think it was driving lower in the stroke. Third round for the last 3 tests and the comp 13 out. Much better everywhere (but still away from very good) and I could keep the pace and attack the rocks with more confidence. And the clock liked my driving better for this final round.

Ok, I think the 10x32 - 0.1 shims offer a bit less damping than 3x32 - 0.15 shims (assuming this would be stock) and the fork blows through the stroke easily if the comp clicks are too far out and the PFP screw adjusted less than 2 turns in. Considering your suggestion to make the stack steeper towards the base shim, I will test on Thursday the following: Current stack:

10x32 - 0.1
30
28
26
24
22
20
18
16
14
12
11 - 0.2.

New:
3x32 - 0-15
30 - 0.1
28 - 0.1
26 - 0.1
24 - 0.1
22 - 0.1
20 - 0.1
18 - 0.1
14 - 0.1
11 - 0.2.

Still it will be much stiffer than the 2T stack but it should be in the right direction... for what I want to have. What do you think Glenn?

Leon

[GMP]

Leon,

That looks like it would soften up the high speed, but if the problem is the fork is riding too low that will not solve it as you know. I guess you have to determine the position of the fork where harshness is felt. A single .15 mm shim is worth three .1s, as a rule, so you were close anyway. I always work with two stage stacks for good compliance in rocks but that's on two strokes. Never have I felt the fork to be harsh high in the stroke on trail trash. Springs correct? Just throwing ideas out.

[Leon_RR250]

Thanks again for your input!

I am assuming the springs are the stock 0.48s which are a bit on the soft side for my 93 kg fully loaded but this is still a mystery since I know half of the history of the fork (and considering how stiff the comp and midvalve were). I hope I can see some number on them the next time I have the forks apart. I thought to play with the stack this week just before the race but I will just try with the previous setting of 16 clicks out for the comp and 1,5 turns in for the PFP since I liked this setting the best until now. The race tests will be a mix of technical slow rocky trails and very fast sections in between. On Saturday I could have started the club race with the previous setting and then try what I tried, to have a better idea for how the fork changed.

For the 0.15 shims I saw somewhere written they correspond to 3-4 0.1 shims (12 max 0.1s for three 0.15s) that is why I thought to increase the 0.1s or use three 0.15s while decreasing high speed shims. Definitely I am not going to use a crossover because I think it will cause the fork to ride lower.

Leon

[GMP]

Leon,

One thing I have never experienced with this fork is a pronounced low riding/diving action. Even on the GasGas, that was a lot heavier than the Beta with more yet on the front wheel. Even with the bleed heavy OEM valving. Sure it can use travel fast, but it never sagged and always felt reasonably supportive. Maybe it's time to revisit the midvalve. Keep the same light stack, but drop the float a little. Why should the 4stroke use the same float as the 2stroke?