Mountain Bike Reviews Forum banner

141 - 160 of 192 Posts

·
Registered
Joined
·
406 Posts
I miss read your initial post. Changes to the velocity stack will have no affect on lock out stiffness


You can add ( or subtract) 20mm shims to the IPA (10mm ID) stack to change the IPA adjust range and get a stiffer or softer lock out. You want to make sure to run at least 2 of the 10x14x.1 shims to allow enough room for the shim stack to have proper lift.

Most of the time, changes to the IPA stack require a eyelet adjustment to keep the stack and zero preload in IPA 1.

Do you know what your current IPA stack is?
IPA stack is
10 x 14 x 0.1
10 x 14 x 0.1
10 x 20 x 0.2
10 x 20 x 0.2
10 x 20 x 0.2

I left the 10mm stack as is as I noticed you needed the 14mm to hold the 20mm off.

I set the compression stack as
8 x 10 x 0.1
8 x 16 x 0.1
8 x 14 x 0.1

Bouncing around the garage it seems better. We are currently under “shelter in place” but can ride locally as long as you bike to the trailhead. Luckily I live 3 miles from a large trail network. However it has been raining here like crazy. The rain is really helping social distancing as people in So. California hate the rain. Yesterday I replaced the brakes on my bike and tuned the shock.

Stay safe and thanks for the help


Sent from my iPad using Tapatalk
 

·
Registered
Joined
·
4,720 Posts
Discussion Starter #142
IPA stack is
10 x 14 x 0.1
10 x 14 x 0.1
10 x 20 x 0.2
10 x 20 x 0.2
10 x 20 x 0.2

I left the 10mm stack as is as I noticed you needed the 14mm to hold the 20mm off.

I set the compression stack as
8 x 10 x 0.1
8 x 16 x 0.1
8 x 14 x 0.1

Bouncing around the garage it seems better. We are currently under “shelter in place” but can ride locally as long as you bike to the trailhead. Luckily I live 3 miles from a large trail network. However it has been raining here like crazy. The rain is really helping social distancing as people in So. California hate the rain. Yesterday I replaced the brakes on my bike and tuned the shock.

Stay safe and thanks for the help


Sent from my iPad using Tapatalk
If you want to make the lock out stiffer, you would need to make the IPA stack stiffer. Your current IPA has a total thickness of .8mm. So the way tuning it works, you would need to keep that stack thickness or adjust the eyelet position to compensate for the change.

Shim stiffness conversions work like this:

Shim thick = equivalent number of .1mm shims:
.10 = 1
.15 = 3.38
.20 = 8
.25 = 15.63
.30 = 27

Using this information, we know your stack of 3 20x.2mm shims has a stiffness value of 24. To get a stiffer lock out you would need to get a higher value than 24. To achieve a stiffer lock out without changing overall thickness, you can remove the 20x.2 shims and switch to (2) 20x.25 shims. This would up the stack stiffness to 31 and the stack would have a total thickness of .7 You can then add 14x.1 to regain the .8mm stack thickness we need to not have to adjust eyelet position. You could also add a 20x.1 if you wanted to up the stack stiffness value to 32. That would be the equivalent of adding a 20x.2 shim without adding any thickness to stack.

We are under a "stay at home" order as well, but its not as as strict as some places. We are allowed to drive to parks as long as we follow social distancing practices when at the park.

Stay safe!
 

·
Registered
Joined
·
185 Posts
Man I'm confused, my shock is December 2018 production, but I have the old rebound config with only one 16x.2 shim, which is already showing deformation after one year. The more important for me though being the compression stack- the IPA is pretty standard, but there is no other shim stack, just 2 spacer shims... Now- I want to get less high speed compression damping out of the shock, how should I go about that in this case? How am I getting any high speed damping to begin with? lol My only guess is the flow is getting choked by the 16mm rebound shim covering ports.
 

·
Registered
Joined
·
4,720 Posts
Discussion Starter #144
Man I'm confused, my shock is December 2018 production, but I have the old rebound config with only one 16x.2 shim, which is already showing deformation after one year. The more important for me though being the compression stack- the IPA is pretty standard, but there is no other shim stack, just 2 spacer shims... Now- I want to get less high speed compression damping out of the shock, how should I go about that in this case? How am I getting any high speed damping to begin with? lol My only guess is the flow is getting choked by the 16mm rebound shim covering ports.
The new tunes didn't go into production until last year if I remember correctly.

Why do you think you need less HSC? I ask because the symptoms of being under damped are very similar to being over damped. Mainly harshness and kicking from the wheel over shooting impacts and using more travel than is ideal, causing a harsh feeling as it hits the more progressive part of the spring curve.

My suggestion is to email tech support and put in a request for a gold piston and some shims. Than run this stack

10x14x.1 (2)
10x20x.2 (3)
8x11x.1
8x10x.1
8x16x.1
Gold piston
8x15x.15 (2)
8x12x.15 (2)
8x10x.2

If you Don't want a gold piston or can't get one, I would run this for velocity stack

8x10x.1
8x15x.1
8x14x.1
Red piston

This will help add some support without excessive high speed damping. You may end up needing an eyelet adjustment. You will know this if you feel a knock after switching compression stacks. This won't happen if you run the stack I listed with the gold piston but can happen with the stack I listed with the red piston as it allows for some backflow through the velocity stack. This can cause the IPA shim stack to slam shut as the shock changes directions, so any float when an IPA1 will cause the noise.

this does not cause any performance issues but can be an annoying feeling. It can also be fixed by adding a 10x14x.1 to the top of the IPA stack, of taking on of the existing 10x14s and bending it slightly so it adds spring pressure to the IPA stack. I'm still testing whether the bending is a long-term solution, but it definitely works in the short-term.
 

·
Registered
Joined
·
185 Posts
Thanks for advice, hoping I'll at least get a reply from the support, didn't have much luck before from the EU one 🤣
I concluded that there is too much damping because I feel a lot of resistance at high compression speeds, it's not the spring pushing back- I can tell the difference, I have the spring pretty much dialed now (king can converted to dual air)
there is no kicking, but the resistance is a bit too high for my liking and makes it impossible to use full travel with the pressure I set. The thing is, I use the same amount of travel pushing hard on flat ground and doing a 1m drop to flat pushing hard instead of absorbing it, that must be the damper, I can hear the oil barely squeezing too, apart from the resistance feeling. It's doesn't ride bad really, but it bothers me that I cannot use full travel (last 3-4mm) with the spring rate I like the most.
Hoping for a positive reply from the support, as shims are quite hard to get by here, and quite expensive on top of that, I wouldn't want to build the stack from scratch :/ Probably would resort to some bodged shim fabrication from left over abs+ shims (filing the diameter down on a drill :p )
 

·
Registered
Joined
·
4,720 Posts
Discussion Starter #146
Thanks for advice, hoping I'll at least get a reply from the support, didn't have much luck before from the EU one 🤣
I concluded that there is too much damping because I feel a lot of resistance at high compression speeds, it's not the spring pushing back- I can tell the difference, I have the spring pretty much dialed now (king can converted to dual air)
there is no kicking, but the resistance is a bit too high for my liking and makes it impossible to use full travel with the pressure I set. The thing is, I use the same amount of travel pushing hard on flat ground and doing a 1m drop to flat pushing hard instead of absorbing it, that must be the damper, I can hear the oil barely squeezing too, apart from the resistance feeling. It's doesn't ride bad really, but it bothers me that I cannot use full travel (last 3-4mm) with the spring rate I like the most.
Hoping for a positive reply from the support, as shims are quite hard to get by here, and quite expensive on top of that, I wouldn't want to build the stack from scratch :/ Probably would resort to some bodged shim fabrication from left over abs+ shims (filing the diameter down on a drill :p )
The funny thing is that with your current shim stacks, you will have very little high speed damping in IPA1. It's the weakest compression stack tested and relies only on the IPA stack for damping.
 

·
Registered
Joined
·
185 Posts
I figured that (from tuning abs+), hence the confusion. Either way I feel quite a bit of damping at high shaft speed, even just after the wheel touches ground, where there is almost no spring force, I always rode with one click of IPA for some support when pumping, the only thing I can think of is the combination of the very stiff IPA stack (it gives little speed dependant damping, but still does some either way- I know that from tuning ABS+, stock stack is very similar, but there is a needle bypass and a bit more preload, the trail stack has more speed sensitivity, but with less preload I'm able to use it effectively- closing the bypass partially or even fully with no harshness) and the partially covered ports by 16mm shim (to my eyes anyway it looks like the oil flow is really restricted)
I'm sure to remove one of the 3 IPA shims, then the lever will have a more usable range (till now click 2 is well stiff enough for climbing- too stiff for riding, 3 doesn't bob when sprinting, 4 full lockout is redundant) for the sake of not changing total lenght, I'll just move the shim behind spacer shims, done this with Monarch with great results, though there were plenty shims inside, so I didn't have to get any other for tuning, I'm surprised with this one shim rebound setup, what with reading how a single shim has really low durability in this position in the abs+ topic, it's quite bent already- probably would break not far from now, surely I'll exchange this one with multiple softer shims, this stiffness was perfect though so would rather preserve it.
 

·
Registered
Joined
·
9,367 Posts
piciu256;14683699My only guess is the flow is getting choked by the 16mm rebound shim covering ports.[/QUOTE said:
The 15mm rebound shims made a huge difference to my old McLeod. Especially having a softer HSR circuit too. I never had to stray from the stock compression stack.

If you can get hold of the shims and don't mind experimenting, I would try the rebound stack Mullen has suggested first with your existing compression. Then after some riding swap to the compression stack he suggested for a comparison.
 

·
Registered
Joined
·
185 Posts
Sure will, just of curiosity- to know if the rebound shim was guilty of my problem, I didn't really feel anything wrong with this stack on the trail.
now all remains is to wait for a response.
 

·
Registered
Joined
·
185 Posts
In awaiting for the response I put the shock together with one less IPA shim, for testing purposes. I definitely prefer the stock setup over this, guessing I like digressive compression damping- lots of support at rider induced movements but allows the wheel to get out of the way from obstacles. Didn't change anything in terms of travel usage, the choking sound is still there, which might confirm the rebound stack as the cause.
If that doesn't fix the issue, I'll just remove the travel indicator o-ring, the bike feels perfect apart from the front-back travel usage (Mattoc 140mm up front)
 

·
Registered
Joined
·
185 Posts
Just a quick question: will 8x14x.1 shims suffice in the lack of 15mm ones? That was all I'm able to obtain without braking the bank, and I'm not able to break the bank atm. not for this purpose anyway.
From my estimating, they just barely cover the rebound ports, hence me being sceptical, if it's gonna work, is there an easy formula for guestimating how much of these .1mm shims would I need to stack to get similar damping as the 16x.2? A little softer stack would do no harm as I'm running the needle halfway open.
Thanks in advance and sorry for spamming one post after the other.
 

·
Registered
Joined
·
4,720 Posts
Discussion Starter #152
Just a quick question: will 8x14x.1 shims suffice in the lack of 15mm ones? That was all I'm able to obtain without braking the bank, and I'm not able to break the bank atm. not for this purpose anyway.
From my estimating, they just barely cover the rebound ports, hence me being sceptical, if it's gonna work, is there an easy formula for guestimating how much of these .1mm shims would I need to stack to get similar damping as the 16x.2? A little softer stack would do no harm as I'm running the needle halfway open.
Thanks in advance and sorry for spamming one post after the other.
14mm shims won't quite cover the ports,15mm is needed.


It takes 8 .1mm shims to be the equivalent of a single .2mm
 

·
Registered
Joined
·
185 Posts
Thanks, ordered 3 15mm shims then, those are avaible where I live,
will go for a
15x.1(2)
14x.1(4) rebound stack, should be plenty slow enough, I won't bother going faster, even though I probably could.
I'll revert the IPA stack to where it was, and if I feel adventurous, and more importantly- able to use full travel, might try the 15x.1 14x.1 velocity stack, crossing my fingers for the ability of using the gold piston, but my hopes are getting weaker and weaker each day which passes with no response.
It's funny how they did reply once when I was forwarded from the US one, but if I write to EU directly, unable to get a response (wrote 3 times on separate occasions till now)
 

·
Registered
Joined
·
50 Posts
I would be interested to know to get a gold piston in the UK. I am happy to pay for it, I just don't know who to speak to to get one.
 

·
Registered
Joined
·
185 Posts
No reply from EU support, as expected...
Anyway, received my 8x15x.1 shims, settled on stock IPA (3 .2 shims)
but added a 14x.1 velocity shim, if you can call it that, put it in place of the 8x12x.2 shim, no more IPA knock
for rebound I settled on 8x15x.1(x3) 8x14x.1(x1) with stock clamp shim, didn't measure. With 3 8x14 shims it was much stiffer than stock 1 16x.2 for some reason, actually it almost felt like there is a bit of preload, anyway, this setup feels pretty nice, the rebound a just a little faster than stock.
Somehow I didn't notice before that I had 2 different spacer shims- a .1 and a .2, I had to lower the spacing .1 to get rid of IPA knock.
It's raining so no testing on the trail, but with the same pressure I'm able to use just a little bit more travel pushing hard at the pedals, which seems to imply it really was the 16mm rebound shim responsible :) Most importantly the IPA stack is back to normal and it feels much better, with .1mm more preload, the full lockout is even more redundant than it was before though ;)
 

·
Registered
Joined
·
4,720 Posts
Discussion Starter #156
No reply from EU support, as expected...
Anyway, received my 8x15x.1 shims, settled on stock IPA (3 .2 shims)
but added a 14x.1 velocity shim, if you can call it that, put it in place of the 8x12x.2 shim, no more IPA knock
for rebound I settled on 8x15x.1(x3) 8x14x.1(x1) with stock clamp shim, didn't measure. With 3 8x14 shims it was much stiffer than stock 1 16x.2 for some reason, actually it almost felt like there is a bit of preload, anyway, this setup feels pretty nice, the rebound a just a little faster than stock.
Somehow I didn't notice before that I had 2 different spacer shims- a .1 and a .2, I had to lower the spacing .1 to get rid of IPA knock.
It's raining so no testing on the trail, but with the same pressure I'm able to use just a little bit more travel pushing hard at the pedals, which seems to imply it really was the 16mm rebound shim responsible :) Most importantly the IPA stack is back to normal and it feels much better, with .1mm more preload, the full lockout is even more redundant than it was before though ;)
That's a pretty soft rebound stack. Where are you running your adjuster?
 

·
Registered
Joined
·
185 Posts
Nevermind, went outside and according to the standard bounce test, the rebound is a bit too fast- bounces above sag point 2 times instead of settling after a bit of an evershoot (like most peopple say it's supposed to and it did before) to get the "recommended" bounce I have to close the adjustment 2/3 of the way, which I guess is a non issue? Don't know what's better for performance- more low speed bypass or more shim stack damping, anyway, there is a weird knock/ click close to full extension with low speed rebound almost closed, I'm pretty sure I put everything together properly, the only change being new stack, but there was no knock before, and it only appears over 3/4 closed, as if it happens when the rebound stack closes?
 

·
Registered
Joined
·
185 Posts
Did some proper riding today, shock set @2/3 closed rebound and 0 or 1 click of IPA (prefer 1) the bike feels amazing! Yes I did some other little changes apart from different rebound tune and the 14mm compression shim (rolled the handlebar forward a little, added 5psi to Mattoc for 20% vs 25% sag and one more click of rebound) but it rides much better than before- the rebound is a bit faster and there is a bit more high speed damping, but the rear end doesn't kick anymore when I jump leaning a bit too far back, like it did before, the shock uses more travel and I feel like it's doing so more efficiently and to top it all, it's not as loud as before- it used to make a loud whistling noise when pushing after a bunny hop etc. and while the sound is still here- it's quieter and a bit lower pitched :) No more knock audible when riding also helps a lot with the experience.
I cannot say more apart from that it feels better than before unfortunately as I have a hard time telling whats actually different :p
 
141 - 160 of 192 Posts
Top