The Tuesday(ish) Tune: High and Low-Speed Damping - Video

Dec 7, 2016
by Vorsprung Suspension  

This week's Tuesday Tune follows up on the last episode's focus on high- and low-speed damping and delves into some setup concepts to be aware of. We take a look at the practical ranges of velocities that adjusters actually affect and how to understand that in a way that translates to relevant on-trail adjustment. Also covered is the process of bracketing, which is a relatively foolproof method of setting up each adjuster individually. Bracketing can be used on any external adjuster regardless of how much you know about the effects of that adjuster - all you need to do is decide whether each change is better or worse than the previous setting. Easy!

There's a few things we need to put out there as well about using this information:
1. Obviously any changes you make to your suspension will change the behavior of the bike. Be smart about this - don't make big changes then go and immediately send it off the biggest jump you can find without spending time getting used to the setting first.
2. Time matters a lot. Keep the time between changes to your suspension to a minimum, so that you have the best memory possible of the previous setting. Multiple adjustments in a single run are a good way to do that. Comparing setups hours or even days later is a really easy way to confuse yourself.
3. Trust your FIRST impression of any change - it is usually the most accurate one. You'll get used to anything over time, and what felt terrible initially may begin to feel normal as you get accustomed to it... even though it was terrible.
4. Getting someone else to make the changes for you, without telling you what they changed in order to eliminate placebo effects. Then re-read point number 1 above.
5. This is not intended to be a complete or comprehensive coverage of all possible setup methodologies. We do simplify and cut out information just to be able to squeeze it all in. If your on-trail experience does not agree with what you expected based on something we've said, your on trail experience should always take precedence as there's almost certainly a rift in the theory as it has been communicated or understood. In other words, trust your own perceptions.
6. Check your tire pressures. They make a lot of difference.

Also, our apologies for missing the Tuesday Tune last week - the Luftkappe product launch left us swamped with too much other stuff to do!


56 Comments

  • + 35
 You're doing an incredible job @VorsprungSuspension.
All you say makes sense, and you only introduce us to the necessary concepts needed to understanding the basics of how suspension works. I really find your videos helpful, keep up the good work!

Shame other suspension companies don't spend the same time making sure we actually get the most out of their products.
  • + 16
 Thanks for the kind words! I think a lot of companies tend to stick to broad generalisations with suspension setup advice for a few reasons - it's really easy to get things wrong when you get very specific, or have people think you've given them bad advice on setup simply because there are so many confounding factors and variables with overlapping effects. It's not that these guys don't know how to set up suspension either, it's more the difficulty in covering every base and communicating every possible aspect. For that reason, I think it is more useful to explain the theory and the concepts so that people can better understand what's going on rather than simply following a process. With that said, not everyone wants to spend hours digesting this kind of information, which is why processes like bracketing are helpful, and why products like Cane Creek's Dialed app and the ShockWiz offer customers an easier route to a decent setup.
  • + 8
 Tire pressure! I usually run higher psi when setting up suspension to kind of isolate the front and rear suspension. Then go back to what you normally run. Don't know how many times I've put new shock or fork on, had a click fest and suspension felt like shit. Turns out it is was tire pressure.
  • + 4
 For sure - tyre pressure can ruin everything!
  • + 1
 @VorsprungSuspension: so is it just about being consistent with that preferred tire pressure so you can eliminate that variable and concentrate on the suspension feel?
  • + 3
 @nickkk: that's one aspect - the other is that tyre pressures that are too high simply destroy small bump sensitivity!
  • + 1
 @bikeetc Why would you do that? The tire pressures are part of the total suspension equations, and if you run a different pressure than normal when setting up the suspension, you could miss some feedback on the actual feel/action of your settings
  • + 1
 @baronKanon: Just saying on initial set up to acctually feel what your shock or fork is doing and not factoring in the tire pressure until you have a good base tune. after that then adjust tire pressure and then fine tune the shock/fork.
  • + 6
 @VorsprungSuspension
Thanks once again for the video.
I suggest you consider doing a video explaining HOW riders can practically test the behavior of the fork/suspension, and what to expect from each adjuster. Where on the trail (or type of terrain) will a rider notice the different types of compressions/rebounds.

Somewhat like the basic "descend a curb, see if your rear suspension is pogoing, increase/decrease rebound accordingly", only a bit more advanced. I know many if us, myself included, consider ourselves quite experienced and attuned to our suspension, but i'm sure you can teach us a couple new lessons there too.
  • + 3
 Thanks for the suggestions. We'll definitely have a good think about the best way we can present that kind of information, as that is potentially very useful!
  • + 5
 Very good advice, that's exactly how I'd do it. Also, thank goodness for the bad closed captioning......http://i.imgur.com/Qi5guts.png
  • + 6
 HAHA! Amazing.
  • + 2
 Another killer video! Having just picked up a new CC DB Coil for my Nomad, this presentation hits the nail on the head. I've always had a decent grasp on suspension tuning but having some visuals helps tremendously. I will be picturing your graphs on the trail next time as Im fine tuning.

I can concur the base tune from CC was really stinkin good. Bike rode great and was just a tad lacking in pop. If anything I could have benefitted from a slightly higher spring rate (my fault) and it probably would have been spot on.
  • + 4
 With CCDB coil I'm sure you'll be one of the happiest Nomad owners out there. People putting simple float and monarch shocks on these things should be shot in their knees
  • + 1
 @WAKIdesigns: agreed. Bike came with a monarch. I ran it for a season to get used to and give it a chance. Bike is a turd with an air shock. But with a coil its amazing.
  • + 2
 @cthorpe: let me guess, excellent mid stroke support and feedback, bottomless feel and bike glues to the ground on Gouts
  • + 1
 @WAKIdesigns: Yep, all of the above plus improved small bump sensitivity. We're talkin like 4 times better. It now rides the way VPP is meant to.
  • + 2
 I'm a bit confused and hoping someone can help me out. After the last video I was understanding that increasing LSC would *shorten* the time before HSC compression kicked in as the pressure would build faster on the valve assembly. However, in this week's video Steve indicates that increasing LSC will do the opposite. What am I missing?

Also, I've been wondering with a negative air spring if there's any significant force exerted through negative pressure, or is that what the equalizing ports are for (in addition to balancing changes in the positive chamber pressure)?
  • + 7
 This gets a little more complex because the axes on those two graphs aren't the same. Increasing LSC does force motion into the HS region "earlier" in terms of what speed it's happening at, because the transition to the HS curve is happening at a lower velocity. However, increasing the LSC reduces the rate of initial vertical response of the WHEEL to a bump as there's more resistance. This slower response results in the tyre conforming more to the bump, which generates a higher net force, subsequently accelerating the wheel more sharply and resulting in higher peak shaft velocities.
  • + 3
 @VorsprungSuspension: Very helpful. Wasn't considering the wheel part of the equation! Thanks for the quick and thorough reply!
  • + 2
 @VorsprungSuspension
Awesome and thank you very much for taking the time to do that - very, very much appreciated.

Can I have your opinion on a question reagarding a Rock Shox Pike DPA please? I was running one of those for two summers and never was able to find that "sweet spot" with the settings. I did a lot of back to back testing - even bracketing - using the same course at the same day and keeping everything else exactly the same (gear, tire pressure, kit, backpack - only some water from the bottle to the belly - so in sum it was the same weigth).

In the end I was running the LSC at the very minus end of settings and only the HSC for adjustments. I had the feeling that the LSC did not do much to get a better feeling. The main thing that bothered me was the Pike using up the first half of travel very fast and not providing much support at all. Running a rather closed position of HSC cured that to a certain point, but not like I wanted it to be.

Did you have similar experiences with Pike´s?
I know the DPA lacks a bit performance because of the DPA mechanism and that was the last time I had the feeling I needed one of those ;-)

Any feedback is highly appreciated as I need to service the charger cartridge and maybe there is something I can do get more performance
(...again - for the 4th or 5th time because the little bugger get´s filled up with air :-) )
  • + 4
 When you say closed position for HSC, are you using a stock RCT3 damper? Or a Fast kit? Not really sure how you'd be adjusting just the HSC otherwise?

The Charger dampers, as stock, are very lightly valved in compression. If you haven't already, try firming up the compression to the Firm tune as per Rockshox's guide. One of the shortcomings of DPA is that it is quite firm at the very start of the travel and very soft in the middle, meaning that if you run it soft enough that the start of the travel is sufficiently compliant, the mid stroke feels unsupportive. The Solo Air variant is similar as stock, which is why we built the Luftkappe for that, but that doesn't help with the DPA unfortunately - your best option is simply firmer compression valving right now.
  • + 2
 @listeryu

The key for me to get my 160 mm DPA Pike to shine was to put in 3.5 volume spacers and then lower the pressure to get around 20% sag. Bottom out resistance, mid range support and a relatively supple beginning stroke. I also run my LSC about 9 clicks from fully open / fast but I'm also a pretty heavy guy (235 lbs riding weight) so that may not apply as much to you.

@VorsprungSuspension:

Excellent Series - very useful!
  • + 1
 @VorsprungSuspension: you are absolutely correct - I mixed up the knobs on my fork - I can only adjust the LSC and the 3 way compression which I was running at the open position. LSC was open (very minus position) as well or 2-3 clicks from very minus to plus position. Anything else gave a rather harsh feeling when riding but the lack of support when pushing the fork was always there.
  • + 1
 --
  • + 1
 @Xorrox: I put in the spacers and it felt better but not like I want it to be honest and also compared to how the Mattoc I used the whole summer feels. Will firm up the compression as sugested by Vorsprung and give it an other try. Thanks for your input regarding sag - I always used abouth 25-30% and I will give it a go with 20% and see how that works.
  • + 1
 So the high speed compression adjuster changes when the high speed circuit engages. How do you change the "slope" of the high speed compression then? Is that a set thing in the valving or is it a function of your spring rate?
  • + 1
 by set I mean pre-determined
  • + 2
 @nhlpat: The gradient of the high speed damping curve is affected either by more oil being forced through a parallel circuit (as happens in twin-tube shocks) or by alterations to the shim stack stiffness or valve geometry. It isn't related to the spring rate as such.
  • + 1
 Wow, what a great series of vids!
I was somewhat of an expert when it came to MX bike suspension tuning, but I've never dealt with anything like the DB Inline Air on my Tallboy 2!
Just got back from beating my bike (and myself) on Slickrock Trail in Moab for a few days, trying to establish the air can volume. I'm running a Pike up front, and luckily it's completely dialed for me, so just trying for balance now.
That CC shock is so amazing, that it's hard to feel anything bad sometimes.
I'm 150Lbs on the bike, and now have 1 full spacer, plus 2 full width strips of volume spacer.
My HSC and LSC are just a little looser than the CC factory setting for the shock (no known base tune for the Tallboy).
One more ride, and then I'll cut the one more full strip off. The shock came with no volume spacers, and after adding a full spacer, it still blew through the travel over small bumps, as it did with none.
I personally feel like the volume spacer set up I have now is on the money, but I have to know.
And the guys at CC have been so helpful that I want to give them my best base tune so they can maybe give a recommendation for the Tallboy.
Thanks again!
Eric
  • + 1
 @VorsprungSuspension Hi Steve, first of all thank you for taking the time to make these videos! Breaking down the mechanics of one specific topic per video is a great format, and I feel I have a greater understanding of the 'science' behind the feedback I get from the suspension and now I know what to do with it to improve my setup.
One question for you regarding the 2017 Rockshox Super Deluxe RC3 shock. I have one on my Trek Slash 29 9.8.
I weigh 68kg (without riding gear) and running the shock at 160psi to achieve my desired 30-32% sag. At this pressure I am using 95-100% of shock travel on 'moderate' trails that I definitely wouldn't consider to have any big hits.
Upon popping off the air can to assess the volume spacer configuration, I see it has 2 of the new funny shaped red tokens, as well as a larger round grey spacer between two thin metal discs. I couldn't spot this grey spacer in the service manual, so I suspect this may be an addition to suit the Slash. Would adding an extra red spacer or two (and dropping the pressure a small amount) be the best way for me to maintain 30-35% sag and increase my bottoming resistance? Information on tuning the new shock is scarce but I'm sure you guys have thoroughly figured the new shocks out already. If there are any other tuning pathways for the compression damping I'm all ears! I feel it could use a little more high speed and a little less low speed compression damping but for now I'm just looking to get this spring curve sorted! Thanks again :-)
  • + 2
 @TomHelly if all you want to do is increase bottoming resistance without affecting anything else much, then yes adding volume spacers is the way to achieve that.
  • + 1
 @VorsprungSuspension Steve thank you for another great class! Just one question, you suggest setting hsc before lsc, does that mean when setting hsc you should first open up the lsc as far as it goes so it has the least affect on the shock? Cheers! Looking forward to next week
  • + 1
 .. If I understood correctly, last time you explained that the hsc dial basically controls at what point hsc kicks in (or alternatively the velocity range considered to be low speed) which would mean opening lsc all the way would make the shock move into the high speed range sooner than if there was a lsc damping force being applied? If that is the case, should there be some level of lsc set whilst playing with the hsc settings?
  • + 1
 Ok, so I just re watched last week and it seems that I got a bit confused! (would be nice to be able to delete comments!) so please forgive my ramblings and to get to the point, what I am asking is; when it comes to setting hsc what should I do with the lsc? Open, closed or somewhere in between?! Thank you
  • + 2
 @dicky1080: Set HSC with LSC very much on the open side. Doesn't necessarily have to be fully open, but at least halfway out. Obviously this relies on the LSC circuit not being able to open to an excessive degree (such that too much oil flows through it and never forces enough through the HS circuit) but most modern dampers are fine for that.
  • + 1
 I agree with everything 100%. But how come I am able to set up my CC DBAir CS without any problem whatsoever, and all the clicks are really changing the suspension, but my Fox 36 RC2 2016 feels like utter feces whatever I do? It's wooden as Pinokio's wiener. Just recently I did exactly that. Went on trail and was so desperate that I switched the fork's rebound to MAX. Even though this really makes no sense in those forks because they become slow as molasses. But I did it and you know what? It was exactly the same. Even though it should pack up the fork and be harsh as hell it was just as harsh as usual. Screw you FOX I'm going home! Cane Creek. Please make some forks already.
  • + 2
 Sounds like something is wrong with your damper if the rebound adjuster is doing nothing - might be worth having that one looked at.
  • + 2
 Did you try your fork only while it was cold outside? By cold I mean below +5°C
I found out that Fox Gold oil behave close to frosen maple syrup when temperatures go down. I replaced the Gold oil with Fox's Green one and it feels better so far. Maybe @vorsprungSuspension can give some complementary thoughts on this?
  • + 1
 Alternatively, the issue could be that you have air trapped in your lowers. use a zip tie down the stanchion dust whiper and equalize the lowers and atm. I have this issue because I live at sea level but ride at 6-8000k ft. above sea level
  • + 1
 How does higher spring rate affects overall performance? Can I use less LSC nad HSC? I suppose, that it will stay more in middle of the travel and higher spring constant can prevent too often bottom out. Do I get it wrong?
  • + 5
 You the man Steve!
  • + 2
 Awesome vid as always.
@VorsprungSuspension any tips for setting up suspension for cold weather with subzero temperatures?
  • + 3
 Get yourself some nice thin oil with a high viscosity index. WPL ShockBoost 2.5wt, Motul VI400, Maxima RSF 3wt all do pretty well there. There are even lighter specialty oils out there - if you're in Sweden I'm sure your local MX shop will have something useful for you. They're less common over here in western Canada though.
  • + 1
 Silkolene PRO RSF 2,5wt
  • + 1
 @VorsprungSuspension: At what temps should you seriously consider changing fluids to adjust?
Is it worth changing just the bath oil? (Quick and easy) Or is it only really to address damping.
  • + 5
 @ReformedRoadie: bath oil isn't such a big deal, but the damper oil definitely makes a big difference. Anything below freezing (0C, or 50715 fahrenheit or whatever it is) it's usually pretty noticeable.
  • + 1
 @VorsprungSuspension: I have a RS fork with charger damper and as far as I understand it's using a pretty thin oil already (3wt ?). Would it be wise to get the oil replaced in it for thinner one if I can find it? For now I try to compensate with faster rebound and less LSC but I am not happy with current performance.
  • + 2
 @VorsprungSuspension: bath oil isn't a big deal? Even when we talk about Fox Gold?

Like I just wrote, I just swapped the gold oil for the green one in the lower legs of my float 36 and found it to be much more supple now when temperatures are below +5°c.
The viscosity of the Fox Gold oil is approximately 10 times higher at 0°c than Fox Green and the viscosity of Fox green at 0°c is equivalent to the viscosity of Fox gold at +40°c... that's a big difference to me! Smile
  • + 3
 @Happymtbfr: The Gold oil turns to something like honey when it gets particularly cold, that is true - it has a very low VI and a high adhesion which creates a thick and stiff boundary layer between the bushings and stanchions. Most bath oils are not affected to that degree, but the increase in low speed damping is very noticeable and can create quite substantial harshness.
  • + 1
 @VorsprungSuspension: thanks for taking time to answer my comment Steve!
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