[essenmeinstuff]

Took a moment and found a link to the Penske site info.

http://www.penskeshocks.com/files/Adjustable_Manual.pdf

Later pages discuss the various piston design formats.

Pretty technical but should be more than enough information to make your brain hurt.

Granted it is not bicycle specific in title but is applicable.

PK

That is awesome. Hopefully getting a roco wc air soon (if the guy doesn't take me for a ride lol).

This is meant to be pretty easy to pull apart, so shim tuning is something I plan on tinkering with!

(also subscribing to thread)

 

[mullen119]

I've got a 2011 R7, and I just did the shim stack mod last night.

I ordered a bunch of shims to play with from these guys: www.racingsuspensionproducts.com

What I really wanted was to swap from the stock XC stack to the Trail stack, which means adding one 17.5x0.2 Speed Shim. I couldn't find a perfect match for that, so I went with a 17x0.15 instead.

With the stock XC stack I had found:

1 click from fully open was beautiful on really rooty, technical stuff, but it had seriously unpredictable brakedive.
3~4 clicks mostly eliminated the brakedive, but was significantly harsher
2 clicks was kindof the worst of both worlds.

So I put in the speed shim last night (took maybe 20 minutes) and went for a nice long ride today. The new stack is definitely a better fit for me, because I was able to run at 4~5 clicks and have no brakedive, but still a nice supple ride. With this setup I still have more platform than I need, so I may add a second speed shim or remove/swap one of the blowoff shims with something smaller. Definitely a nice mod, though.

Another option to try, assuming you have a shim to use, would be putting a smaller speed shim in. Say 15-16mm x .15. This would allow for more oil flow around the speed shim without the need for the shim to flex as much, giving better oil flow without taking more preload off the rest of the shim stack. I'm afraid that if you have two speed shims, the stack may not have much preload left, making for too weak of a stack. If you do add a second speed shim, You will probably want to add a few more shims to the stack to stiffen it up.

 

[newfangled]

^ thanks. My shims are now in the parts box, but I think what I got was 19x.1 (narrower blowoff shims), 17x.15 (my "speed shims"), 17x.1 (narrower speed shims) and 15x.1 (smaller speed shims). So I've got lots to play with. To start with I wanted to get as close to the stock Trail stack as possible, and then work out from there.

There's also a note in the Manitou techdoc that "For TS or ISO Air systems, an extra 5-10cc of semi-bath oil on the air piston will increase the ramp-up of the air spring, reducing bottoming and improving control overall for some riders." I may do that before changing the stack again, just to see what sort of effect it has.

 

[mullen119]

^ thanks. My shims are now in the parts box, but I think what I got was 19x.1 (narrower blowoff shims), 17x.15 (my "speed shims"), 17x.1 (narrower speed shims) and 15x.1 (smaller speed shims). So I've got lots to play with. To start with I wanted to get as close to the stock Trail stack as possible, and then work out from there.

There's also a note in the Manitou techdoc that "For TS or ISO Air systems, an extra 5-10cc of semi-bath oil on the air piston will increase the ramp-up of the air spring, reducing bottoming and improving control overall for some riders." I may do that before changing the stack again, just to see what sort of effect it has.

If you end up taking it apart, I would try the 15 x.1 by its self first and see if you like it. If not I would try both 17mm shims and add the 19x1 to the blow off shims to help compensate for the loss in stack preload. Adding the oil to the air spring is always a good thing if you have a bottom out problem or the feeling of a weak mid stroke.

Make sure to change only one thing at a time though so you can see what affect each change makes on performance. It usually takes a few tries, but you will end up with awesome fork.

 

[newfangled]

Yeah, thinking about it a bit for a few more minutes...with the new stack there's no bottom-out issue, so adding oil on the spring doesn't get me anything. I've got to go back to the graphs in the techdoc to see what looks good.

 

[zenkem]

Manitou's Marvel Pro and Real Custom Tuning - Eurobike 2011 - Pinkbike.com

 

[solitone]

Absolute Plus Tuning Kit

Manitou's Marvel Pro and Real Custom Tuning - Eurobike 2011 - Pinkbike.com

Interesting! So now it's official, they'll offer the Absolute Plus Tuning Kit.

 

[newfangled]

I wonder how much the kit will cost? The moto ones online are upwards of $100, which isn't a lot in the grand scheme of things, but which seems geared more to a shop/team than to the home tinkerer.

As for my R7, adding the extra velocity dependency has made it so much better and I think I'll be keeping my current stack for the foreseeable future. I know the R7 is a bit of a specialized fork, but I don't know when the stock XC stack would ever be better than that trail stack, unless it's for people who ride trails that have absolutely no technical features.

 

[mullen119]

The thing that that has me interested in the kit is that it comes with multiple pistons. I am wondering if there is a difference in the ports on them or if they are just different OD dimensions for the different fork stanchions. Shims are easily bought if needed and solitone posted the contents of the tuning guide, so if the pistons do not have different port designs, the kit is pointless to mtbr users.

 

[rupps5]

I have a tower pro fork and like the ride with the compression set to 3-4 clicks from soft. When the compression is set to 3-4 the fork bottoms out very easily and often. The rebound is set to the middle.

I would like to have the fork set to 3 clicks and have it ramp up quicker so it will not bottom out as easily. So I would think adding a shim to the hsc stack would be the right thing to do.

What do you guys think?

 

[mullen119]

I have a tower pro fork and like the ride with the compression set to 3-4 clicks from soft. When the compression is set to 3-4 the fork bottoms out very easily and often. The rebound is set to the middle.

I would like to have the fork set to 3 clicks and have it ramp up quicker so it will not bottom out as easily. So I would think adding a shim to the hsc stack would be the right thing to do.

What do you guys think?

Its hard to answer that question without knowing a few other things first.

Mainly, how much do you weigh? When you fully close your LSC, is your fork fully locked out? If so, how much force does it take when you push down to make the fork move?

If it takes a a pretty good amount of force to break the lock out, then adding a shim would not help you out very much because the shim stack would already be fairly strong giving you a good amount of HSC. If it breaks free from being locked out without much effort, then your current stack is fairly weak and there is not much HSC. Adding a shim would help only if the stack is on the weak side. If its not, your problem is elsewhere.

When it comes to bottoming problems, Its normally caused by the fork being under sprung for the riders weight. In that situation, the damper will be ineffective. Your fork has a small coil spring that is used for the first 20% or so of travel, after that the air spring kicks in. I would up your air pressure a few PSI to help with the bottoming. The small bump sensitivity should not be effected to much since the intitial travel is absorbed by the coil, but it should increase your bottom out resistance. If you are running more then 25-30% sag, you may need a stiffer coil.

Hope that helps.

 

[newfangled]

I guess it's been about two months now since I reshimmed my R7, and I'm totally impressed. I like running 3-clicks too, but I was having problems with nasty brakedive. So like mullen is saying it could just be a spring setting. For brakedive and pedalbob though, adding a speedshim worked beautifully.

 

[mullen119]

I guess it's been about two months now since I reshimmed my R7, and I'm totally impressed. I like running 3-clicks too, but I was having problems with nasty brakedive. So like mullen is saying it could just be a spring setting. For brakedive and pedalbob though, adding a speedshim worked beautifully.

Im glad to see this thread helped you find what you were looking for:thumbsup:

As for rupps5, If we find out he is properly sprung, and doesnt care about a firms lock out, Changing from a platform style stack to more of a true HSC stack by adding a speed shim could be a possible solution. To me, its the only way to have it set up, but I also hate the platform feel of any damper, front or rear.

 

[rupps5]

I weigh 165 without gear.

Messed around with my fork and here is what I got:

original setting:
-70 psi
-sag 18mm -lsc open
-lsc closed and running over a 4x4 in the basement test. Went through 35mm of travel

setting 2:
-85 psi
-sag 19mm -lsc open
-lsc closed and running over a 4x4 test. Went through 37mm of travel

now the test and sag measurements ares not perfect but they are the average of taking each measurement 5 times. So why am I sagging and using up more travel at a higher psi?

I do not care about lock out, I have never used it on any fork and would rather have a true hsc stack.

 

[mullen119]

I weigh 165 without gear.

Messed around with my fork and here is what I got:

original setting:
-70 psi
-sag 18mm -lsc open
-lsc closed and running over a 4x4 in the basement test. Went through 35mm of travel

setting 2:
-85 psi
-sag 19mm -lsc open
-lsc closed and running over a 4x4 test. Went through 37mm of travel

now the test and sag measurements ares not perfect but they are the average of taking each measurement 5 times. So why am I sagging and using up more travel at a higher psi?

I do not care about lock out, I have never used it on any fork and would rather have a true hsc stack.

The way your fork spring works, Adding air pressure only has a small effect on the amount of sag you get, and at higher air pressures, effect gets smaller.(because the coil spring moves for the first part of travel, the air spring kicks in deeper into the stroke.) It sounds like you have an acceptable amount of sag, so your coil should be correct for your weight.

Running over a 4x4 wont be a very good test because there are many variables that can change the result.(speed, body weight distribution, and body reactions). What you really need to do put in a full ride at 85psi and if it helps the bottoming.

As for your shim stack, adding a speed shim would completely change the feel of the damper. What it would do is take preload off the shim stack making it weaker, and would lose the platform feel to it. Doing this would allow you to run more LSC (say 4-5 clicks) without losing the small bump compliance and without the harsh spiking you feel when running more LSC with your current stack. It basically will create a smooth transition from the LSC to the HSC. This could help you because as your run more LSC, it will force more oil flow through the HSC stack, giving you more overall damping.

 

[newfangled]

^ like you're saying, before I added the speed shim I had my fork set so that it wasn't beating me up on the rootiest, choppiest sections of my trails. After the speed shim was installed the fork didn't spike nearly as badly (or at all, really) on the choppy stuff, so I was able to up the pressure and the LSC. Looking back over this thread, I guess that I used to run at 1-2 click open (I thought it was 3), and now I'm at 4-5. The behavior is totally different.

 

[rupps5]

Just got back from a ride with 85psi and I did not like it at all. I did not bottom the fork as much but it was just too stiff. I ended up with the rebound and lsc all the way open to try to get the fork to soak up more bumps but there was just too much air. So I think I will try 77psi for the next ride.


I am interested in trying the speed shim. Where would I get one and what dimensions does it have?

 

[mullen119]

Just got back from a ride with 85psi and I did not like it at all. I did not bottom the fork as much but it was just too stiff. I ended up with the rebound and lsc all the way open to try to get the fork to soak up more bumps but there was just too much air. So I think I will try 77psi for the next ride.

I am interested in trying the speed shim. Where would I get one and what dimensions does it have?

Look over the information in this link: http://solitone.interfree.it/ABS+ Tuning REV 3-10-2011.pdf

It can be somewhat hard to understand at first, but it gives great information on how the different shim stacks effect the damping curve.

I would suggest starting with a stack consisting of (2) 17.5mm OD x .02mm thick shims on the piston, followed by a 15mm x.02mm followed by a 13mm x .01mm. all with 8mm ID's. That would be a pretty strong stack with no platform.

That is just my suggestion though. Taking the time to learn the information in that link will help you decide what stack to go with. It really depends on what you are looking for performance wise from your fork. Generally speaking, the XC series of stack in the link are going to have a platform feel. The Linear series is a true HSC stack with no preload. And the trail series is a a mix of the two with a small amount of platform, but with much less spiking then the XC series.

 

[rupps5]

Thats funny I just read that pdf a couple of minutes ago. I like the sound of the linear stack. The whole reason this fork was bought was to play with the shim stacks. Time to order a bunch of shims.

There are a couple of links to shims in this thread but I have not seen a 17.5mm OD x .02mm for sale anywhere. Do you have to get these from Manitou?

 

[newfangled]

^ I went with a 17x0.15 from here: Racing Suspension Products. I bought eight to play with, but so far the 17 is the only one I've used.