Rookie MTB questions!

You know how you said that someone should have told you to read the manual, well to find all your blue knob answers, read the manual! Haha.

Not sure which shock brand that is but assuming that it’s either RS or Fox, they both have great websites that explain everything. Fox forks and shocks also have a four character code on them that identifies the tune which you can enter into their website and it will give you extra information.

The good thing between brands is that they use the same colour coding for the knobs and they all work the same way.

Blue is compression damping. More to the + and the shock will get stiffer and harder to actuate as the oil chambers get closed off. Going - and the damping will be reduced. A heavier rider might want more damping (towards +) as they will blow through travel faster (inertia and all that jazz).

The red dial is the rebound speed. This is used to control the speed at which the fork returns to it’s open stroke (uncompressed length). If you were to find, for instance, that you are going downhill on some rough terrain and the hits seem to be getting harder, or you feel like the suspension isn’t working, then there is every chance that the rebound is too slow and the suspension is basically jacking down in it’s stroke and not returning in readiness to take the next hit. The rabbit is faster rebound, the turtle is slower.

When making adjustments make use of common motorsport tuning parlance. Don’t go one click at a time. Go four. This will give a noticable difference and will tell you straight away if you’ve gone too much. If it’s too much, come back two clicks and test again. If it’s not to much, obviously progress another two clicks. You’ll never feel a difference one click at a time. Be extreme first and then come back.

Also test your new settings on the same section of trail and on the same lines. If you try out a new setting in another trail you have lost your point of reference. You don’t see race cars making an adjustment and then heading out on a different race track.

And also adjust one setting at a time, ie rebound only or damping only or pressure only. Eliminate one thing at a time otherwise you will not know what it was that actually made the difference.

A way up the thread you were looking to take the air shaft out of the fork. No one mentioned that when removing the top nut on the fork first let all the air out, unless you want a 32mm hole through your skull…same goes for the rear shock if fitting bands to add progression…let the air out.

An item to consider is an MRP Ramp Control. This is a cartridge that replaces the top nut and Schrader valve on the air side of the fork. Once installed you can adjust the dial to increase or decrease progression of the fork in the same way as adding or removing tokens but without having to disassemble your fork, and can be done on the trail. Coming up to some big drops…wind on the progression…nice flat trail, wind it off. The Ramp Control is equal to having between 1 and 4 tokens in the fork. There are other fork tune kits available on the market but the MRP is one of the eaiser to use.

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You may be a good candidate for a Shockwiz. You can either buy or rent them. It’s actually better to have 2 of them so you can analyze front and rear suspension at the same time.

I read the whole manual and tuning guide and I was either too dumb or inexperienced, or both, to figure out the difference between cable-actuated compression dial (black) and the manually adjusted dial (blue).

I think I have figured out rebound adjustment.

The manual has no pictures of my actual shock, but more generic descriptions. I suspect the blue knob is low-speed compression damping, whereas the cable-actuated black dial “threshold” something or other, which I have interpreted as “lockout, 30% stiffer, and fully open” for the 3 positions.

Weirdly, the RockShox tuning guide PDF has detailed discussion and diagramed explanation of how sag, rebound, and low-speed compression (LSC) damping work (pictured below), but no detailed discussion of how the “threshold” lever works.


This is all that’s said about the threshold feature, which is odd, because it’s the one that is most likely to be used most frequently, given the remote availability:
image

It seems like the threshold adjustment is like “soft, moderate, locked out” but they say nothing about increased stiffness throughout the full distance of shock compression, which their definitely is when the adjuster is in the threshold (middle) position.

Does anyone have any differential information between the LSC dial and the threshold dial on the rear shock? Looking for nuanced discussion about how they work for my understanding. Is the threshold remote-actuated 3-position dial how one tunes High-Speed Compression?? If so, I’m sure I can read a useful article on HSC vs. LSC and get this all sorted out.

I’m getting handy enough that I could take the thing apart and probably figure out what they do and why, but I’d prefer not to disassemble the shock for investigatory purposes!

Yep, this is precisely how I learned… except I just maxed it out in either direction then zeroed in on what I liked.

I’ve been taking detailed notes. :slight_smile:


Yep, definitely been doing this outside of what is specifically noted in the images above. Following the scientific process for sure :wink: (ie. change one variable when I really want to learn something)

Heard! (I watched RockShox youtube videos on fork & shock servicing yesterday, among other servicing videos, so feel capable here.)

Fascinating and sounds quite valuable. Googled it. Awesome. This seems like a no-brainer install on most bikes these days. Getting one now.

You’ve got a Scott have you not? The three position, cable actuated dial on most of their rear shocks is used to change travel in the rear suspension from zero, then some halfway point (for climbing or easy terrain), and then to fully open. To get these settings they play with the compression damping. Perhaps this is what you’re looking at and most likely the information will be in a Scott manual as the shock is tuned specifically for them.

Fox do a similar thing with their CTD, or climb, trail, descend.

In fact all forks or shocks do this type of action if they only have a three position damping dial.

Personally I don’t like these three position dampers. Just give me a lockout and let me tune the rest to suit my weight and riding.

The Ramp Control of course comes standard on MRP forks, and Formula do something similar on the Selva fork, but it goes about it in a different way. Why RS and Fox haven’t done much in this area yet is beyond me?!?! Putting tokens in and out means you open the system to contamination, risks people not letting air out, and the pressure will never be equal between two setups since you let it all out in the first place.

Ahh, bikes. Such simple contraptions.

Great points all around here. I’m so new to MTB that I didn’t realize MRP made shocks haha. I see that they make more than their little device now :slight_smile:

Yep. Scott Spark, RockShox SID Ultimate Fork and RockShox Nude something or other Shock.

Meaning that it only allows 50% travel?

That seems to oppose what the RockShox manual and tuning guide said, which mentions only higher threshold for movement of the shock. Certainly it does FEEL like having it in the middle position of the 3-position lever puts it at 30-50% stiffer travel. Are you saying that it actually attempts to limit total travel distance or just makes it X% stiffer?

I have the Scott manual, RockShox manuals and tuning guide, and the most relevant bits have been pictured in this thread in my previous reply, unless I’m missing something.

Is this “damping” you speak of, compression damping? Assuming yes. If so, is it HSC or LSC damping, or neither? I guess what I’m getting at is that there is a black dial and a blue dial that turn somewhat independently of each other and I’d like to know if they’re just two distinct ways to change the same thing (ie. low-speed compression damping), or if they have independent effects.

RS info on the nude shock. If I recall correctly if you go to the service section you can input the shock serial number and get all the relevant information.

I’m using the term damping in it’s truest form being a system that controls the speed of a springs action (be that spring be a coil, air, or a leaf).

The LSC controls the shock through bigger, less frequent hits. Think sequential drops like spaced out steps.

The HSC controls the shock through faster hits, like closely spaced steps or washboard brake divets.

The terms low speed and high speed do not relate to the speed you are going. It refers to the speed that the fork or shock is stroking through.

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The nude shock explained more fully here

https://www.scott-sports.com/global/en/page/twinloc

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Thank you very much for your help!

You are correct.

I’m going to be such a PITA with the below response, so, please accept my 1000 apologies in advance.

Got it.

Understood. Flowy big compressions at lower rate of shock compression.

Got it, quick hits, square rocks etc.

Understood.

I read the whole RS info page on Nude shock, and I read this page in full:

(and watched all 5 vids on the page).

So twinloc (3-setting remote shock and fork control) reduces air volume as its method of “compression damping.” That twinloc lever on my handlebar pulls the black thing in the original pictures (which the blue thing is attached to, and also turns with… but also turns independently).

So my questions that remain are:
If the blue dial (+/o/-) setting is LSC adjustment, and the black dial is the twinloc feature…how do I adjust HSC? Or is that what the twinloc is doing? Seems like twinloc is creating HSC & LSC damping, but probably greater effect at LSC, by dramatically reducing shock air volume.

If so, is my below understanding correct:

Blue dial = LSC.

  • “+” = more damped, ie. “firmer” under LSC conditions
  • “-” = less demped, ie. “softer” under LSC conditions
  • “o” = in between.

Black dial = twinloc = HSC & LSC… and it’s the only way my bike has HSC damping adjustment?

I’m cool with that! Just want to make sure I know how to think about it. Does that all seem right?

Not all shocks come with both high and low speed compression damping. They make us pay more money for that.

Majority of forks only have low speed adjustment which is why volume reducers a such a big thing as you end up running lower pressure to handle the fast hits, but then you use up all the travel fast and bottom out. Increasing the progression by reducing the air volume slows the fork or shock later in it’s travel as it’s literally getting harder to compress.

HSC will be another dial, still blue, but with HSC stamped onto it. Sometimes this is within the other LSC dial.

No probs with the questions. Learning stuff helps a bucket load in the scheme of things, including not being taken for a proverbial ride by a bike shop when you want a service and they start saying everything needs replaced

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Spark twinloc explained:

https://www.scott-sports.com/us/en/page/twinloc

Thank you! @handynzl beat you to it yesterday :wink:

SUPER useful info. Thank you!! I think I understand my suspension fundamentals completely now. Definitely looking forward to getting this dialed and putting in volume reducers in my rear shock, as well as the MRP Ramp Control in the front.

Do you happen to know if there is a similar device made by MRP or others that can be used for rear shock ramp rate adjustment on the fly??

Not as yet. The closest I think is the Meg Neg from RS but this only works on certain RS shocks and highly doubtful it will work on a Nude shock since this is a proprietary Scott/RS unit. It’s also not acting as something to increase progression (it works on the negative side of the chamber, hence the Neg in the name)

If anyone was developing something, it would be a company like Vorsprung https://www.vorsprungsuspension.com/

Volume spacers for RS rear shocks are rubber bands. Here is a half decent video on what needs doing: Ask a Mechanic: Adding RockShox Volume Reducer Spacers to your Shock - YouTube

Interesting. Cool company.

Looks like the Nude takes these guys as spacers: https://youtu.be/ngdHH8Q2Zs4?t=160

I’ll play with the MRP in my fork and see what increased progression feels like.

My wife currently still doesn’t use full travel even with sag set to 30% and no tokens in fork, so probably not going to increase progressiveness for her until she bottoms out at least once.

You do want to bottom out the fork / shock occasionally (doesn’t need to happen every ride, mind you!), just so you are getting all that bump eating goodness working for you.

Could be that there is too much air pressure in her fork, or alternatively too much oil in the stanchions (should only be a few tens of milliliters) as this can stop you reaching full travel. If she is light of mass then she might actually require a different tune in the fork. This involves playing with the shim stacks and should only be done by a suspension professional. There are likely a few proper fork service options available to you that deal only in suspension service and tuning. When it is time to have the fork fully serviced (after about 200hrs), I’d find someone that can do a little tweak or two to the shims for a lighter rider. Some (not all) womens specific bikes will come with lighter tunes in the fork and shock, and not just be a pink frame instead of blue.

All depends on how much you want to spend on the hobby!

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Don’t be afraid to deviate from the manufacturer recommended suspension pressures. It’s rare that they are actually what riders use. And yes, you are supposed to bottom out from time to time and get far into your travel most of the time. You are carrying around X mm of travel, you should be using it to its full potential.

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I plan on becoming a pro at all of this because we travel and work remotely from our RV year-round.

For now, we’ll run her sag at 30-32% front & rear and see if we can’t get her working towards more suspension usage.

Got any trustworthy links to videos on playing with shim stacks? (Currently, I’ve never so much as heard of a shim stack :slight_smile: )

I’ll be doing the 200-hr services, most likely.

She’s ~140 pounds + 6-10 pounds of gear/nutrition/hydration most days.

I’m 210 & I can bottom out her fork by looking sideways at it. Given that, is it still possible that there is too much oil in the stanchions? I’m thinking, no, because oil is non-compressible and if it were the thing limiting full travel it would prevent it under any conditions, right?

She uses 60-75% travel most rides. When she rides as aggressively as she’s comfy with, she’ll use ~85% travel.

For reference, we’re both riding used models of the Nino Schurter Scott Spark RC 900 WC AXS bike. Neither of the previous owners rode either bike much, or added any tokens to either fork so I suspect both bikes are still fully stock with regard to suspension.

Have you had her fork open at all? Every so often forks are shipped with tokens unknown to the user.

A kicking off point for air pressure in forks (I was once reasonably reliably informed) is to take a persons weight in kg, and use that as the PSI setting, so a 140lb person at 63.5kg would give a fork pressure of 63.5psi. I’ve generally used this as a starting point myself, but for me personally I find this too harsh to my liking and I end up around 10psi lower than if I used this method.

Adjusting sag will get you to bottom out, but this also chews up some of your available travel, and may also mean that the fork sits in the bottom of it’s travel, rather than the middle or towards the upper end (always nose down). Most forks should have 20-25% sag. This conundrum is solved using tokens - decrease the air volume, increase the progression, lower the air pressure…

I haven’t watched this, it was just the first hit on Tellytubby:

The 200-hour service can be done by the home mechanic with the correct tools and some knowhow, so I think this is achievable for you. The tuning the shim stack is a bit more specialised and if not done correctly, say goodbye to the damper!

For 200-hour service, there are enough videos on Tellytubby from GMBN, MBR, Sram, Fox, etc that go into this. Correct tools is generally what holds people back.

With reference to oil levels, if you can actually bottom the fork, then it is indeed not the oil level. If you can’t, then this is a possible cause for being unable to fully compress the forks, even with a minimal amount of air pressure.

I think for your wife you’re really just looking at the spring rate - a mix of air pressure and volume.

This is what you’d be playing with inside a rear shock:

image

An article from Pinkbike:

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