Fork tuning and Volume reducer ??

CrankAddictRich

CrankAddictRich

Well-Known Member
Hey guys.. I've got a question and I'm hoping the locals can give me some help. So I just recently got my Fuse all set up with the Rockshox Pike fork and XT bits and pieces and now I'm trying to dial it in a little bit more. I've watched a bunch of videos explaining the different adjustments for the fork, but I'm hoping you guys can give a little bit more clarification.

The fork is a 120mm travel, Rockshox Pike. I've set the air pressure at 100 psi based on my weight + normal riding gear. I've played around with the rebound adjustment and found a setting that seems to be strong give a nicely controlled return without too much bounce and not soft enough that the fork packs up. Today, I decided I'd pop open the fork and see what kind of effect the volume reducer spacers have. When I unscrewed the air valve and pulled it out. I found that the fork already had 4 volume reducers installed. Its my understanding that this is the normal configuration for a 120mm Pike. I installed 1 volume reducer and put the fork back together, and set the pressure back to 100 psi. Right away, the fork felt noticeably stiffer when I first got on it... My immediate thought was, "whoa, I don't like that, I like it better the other way." But then as I rode it a little more and cycled the fork a few times, it seemed to feel better. I have a fairly good size drop in my front yard, maybe a 16-18" drop over some roots, down to the street and I practice going up and down that fairly quickly. Is that normal for the fork to feel super stiff right away when you first pump it up and then even out? Also, Its' my understanding that I can probably run a little bit lower pressure now in the fork to get some small bump compliance because the fork will stiffen up more as it compresses because of the volume reducer?

Thanks in a advance.
 
CrankAddictRich said:
Hey guys.. I've got a question and I'm hoping the locals can give me some help. So I just recently got my Fuse all set up with the Rockshox Pike fork and XT bits and pieces and now I'm trying to dial it in a little bit more. I've watched a bunch of videos explaining the different adjustments for the fork, but I'm hoping you guys can give a little bit more clarification.

The fork is a 120mm travel, Rockshox Pike. I've set the air pressure at 100 psi based on my weight + normal riding gear. I've played around with the rebound adjustment and found a setting that seems to be strong give a nicely controlled return without too much bounce and not soft enough that the fork packs up. Today, I decided I'd pop open the fork and see what kind of effect the volume reducer spacers have. When I unscrewed the air valve and pulled it out. I found that the fork already had 4 volume reducers installed. Its my understanding that this is the normal configuration for a 120mm Pike. I installed 1 volume reducer and put the fork back together, and set the pressure back to 100 psi. Right away, the fork felt noticeably stiffer when I first got on it... My immediate thought was, "whoa, I don't like that, I like it better the other way." But then as I rode it a little more and cycled the fork a few times, it seemed to feel better. I have a fairly good size drop in my front yard, maybe a 16-18" drop over some roots, down to the street and I practice going up and down that fairly quickly. Is that normal for the fork to feel super stiff right away when you first pump it up and then even out? Also, Its' my understanding that I can probably run a little bit lower pressure now in the fork to get some small bump compliance because the fork will stiffen up more as it compresses because of the volume reducer?

Thanks in a advance.
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My assumption is that it just needed to be cycled a few times to equalize the negative air spring.
 
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I know you haven't had that fork very long and probably don't have many miles on it at all. Have you used all the travel on it? In my newb basic understanding of these things you want to add volume reducers/make the fork more progressive if you are using all the travel too easily. The opposite is also true. If you never come close to using all of your travel you should take volume reducers out.

Sag is set based on rider weight. Did you set your fork to 100psi based on your weight and a chart in the manual or based on the amount of travel used when in the attack position all suited up in your riding gear? I found the recommended pressure to set the sag on my fox 34 was close but not perfect.
 
Remember, PV=nrT, so if you lower the volume, you need to lower the pressure, one of the main reasons people run the tokens is to be able to run lower pressures for more small bump sensitivity
 
100 psi seems like a lot I find the air pressure chart on the fork to be way to high usually . Pikes also have a negative chamber that needs a couple good cycles to balance out
 
I find that I want the least amount of high speed compression that I can get around here. Small bump and square edge performance is way more practical than big hits. Generally around here you don't get your bike 5ft in the air so I dial out all the high speed compression. Which is putting more tokens in IIRC.
 
sptimmy43 said:
I know you haven't had that fork very long and probably don't have many miles on it at all. Have you used all the travel on it? In my newb basic understanding of these things you want to add volume reducers/make the fork more progressive if you are using all the travel too easily. The opposite is also true. If you never come close to using all of your travel you should take volume reducers out.

Sag is set based on rider weight. Did you set your fork to 100psi based on your weight and a chart in the manual or based on the amount of travel used when in the attack position all suited up in your riding gear? I found the recommended pressure to set the sag on my fox 34 was close but not perfect.
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Yea, I wasn't playing around with it because I felt I needed any change, per say, more than anything... I was just trying it out to see how it felt. Its a pretty easy thing to swap in and out, so I can put it back to the way it was in like 5 minutes.

DargSide said:
Remember, PV=nrT, so if you lower the volume, you need to lower the pressure, one of the main reasons people run the tokens is to be able to run lower pressures for more small bump sensitivity
Click to expand...

Gotcha... don't know what the equation is, but the rest of the words make sense to me.


Ryan.P said:
100 psi seems like a lot I find the air pressure chart on the fork to be way to high usually . Pikes also have a negative chamber that needs a couple good cycles to balance out
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Yea... maybe it is a little too high, still playing with that too. 100 psi is what I ran on the other fork, the Suntour Raidon and its completely understandable that it will be something different on this one. I weigh like 165-170 so that's about 180 with all my gear on, which put me right around the 95-100 psi mark on the RS guide. Thanks for confirming that it needs to cycle a few times.

gtluke said:
I find that I want the least amount of high speed compression that I can get around here. Small bump and square edge performance is way more practical than big hits. Generally around here you don't get your bike 5ft in the air so I dial out all the high speed compression. Which is putting more tokens in IIRC.
Click to expand...

Hmmm... gotcha.
 
In general I agree with Luke's thinking, however I put 2 tokens in my 160mm Pike because I occasionally do get 4-5ft of air in a couple of spots around here. However, since you're not on a big-hit bike I would experiment with running a couple of tokens and lowering the air pressure until you reach the suppleness off the top/support that feels best to you. If you have the RCT3 version, I would run the compression wide open when you dial it in and keep it as your default setting. If you need pedaling platform on a fireroad or race, just turn the nob to the middle setting or full stiff. When you have it all dialed in, write it all down so you don't forget it.
 
gtluke said:
Generally around here you don't get your bike 5ft in the air so I dial out all the high speed compression. Which is putting more tokens in IIRC.
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This is wrong , tokens only affect ramp up towards end of travel they have no affect on high or low speed compression settings . More tokens more progressive spring curve , less tokens more linear spring curve . I'd suggest loading it up with tokens then dropping pressure to 60 or 75 psi and you'll have the small bump suppleness that will still resist bottoming out
 
Ryan.P said:
This is wrong , tokens only affect ramp up towards end of travel they have no affect on high or low speed compression settings . More tokens more progressive spring curve , less tokens more linear spring curve . I'd suggest loading it up with tokens then dropping pressure to 60 or 75 psi and you'll have the small bump suppleness that will still resist bottoming out
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Seems the same end result. I don't have anything that uses tokens, I have HSC and LSC knobs but just giving my input in tuning for east coast.
 
27-%20Transportation%20Tokens%20_nyc_sub1.jpg
 
I run mine without tokens for a linear feel. I use the compression knob to dial in the fork for different parks. Works well if doing multi park rides where terrain could be really different.
 
gtluke said:
I dial out all the high speed compression. Which is putting more tokens in IIRC.
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Your theory about tokens acting like high speed compression is still wrong less or no tokens would be similar to backing out the compression .
 
I set the sag on my fox 34 to spec, after several rides in different parks it was not getting full travel, even with some nice drops.

Removed 1 volume spacer, set the sag and it was the same PSI. Now it will use full travel on the big hits. This never seemed to change the small bump softness.

I would like more small bump compliance, if possible. I run it full open no compression at all. But reality is this is the best fork i have had. the chit just keeps getting better.

thoughts?
 
Dingo said:
I set the sag on my fox 34 to spec, after several rides in different parks it was not getting full travel, even with some nice drops.

Removed 1 volume spacer, set the sag and it was the same PSI. Now it will use full travel on the big hits. This never seemed to change the small bump softness.

I would like more small bump compliance, if possible. I run it full open no compression at all. But reality is this is the best fork i have had. the chit just keeps getting better.

thoughts?
Click to expand...

The point of tokens is to take up volume in the air chamber, which has the effect of making the stroke less linear. When you add a token, you typically run less air pressure than pre-token. This should give you a more supple initial stroke, with a ramp up in the last few mm of travel. Takes trial and error to get it just right. Sounds to me like you were running too many PSI with the token installed. If you put the token back in and run less PSI, your net effect should be similar. Try it and see if the initial stroke improves, or not, to your liking. For those of you with forks without tokens, adding oil to the air chamber has the same effect. Do it a few mL at a time.
 
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