Ohlins Suspension -Shock Dyno Basics

[@skyway2k]

Just want to say thank you for making this video! Just bought my shock dyno as I’ve always been fascinated with shocks and I love working with them and trying things. So far, my seat of the pants feel on the track has been my only feedback. Looking forward to opening new doors of learning and really understanding what is going on!

[@theohlinsguy4649]

Excellent. Enjoy the journey

[@stopherrr]

Very educational! Thank you sir! Looks like the plot you hate looking at takes into account the direction of velocity. The plot you like looking at absolute velocity which basically means speed which doesn't not take into account the direction. Essentially the same plot. If you flip over the force vs velocity plot over the y-axis, you get the exact same plot as force vs absolute velocity.

[@theohlinsguy4649]

Thanks!

[@MotoTechDE]

Thank you for your content. It's really refreshing to see (as you explained by yourself over and over) and hear a guy that knows his stuff. Unfortunately I'm from germany and have a really competent suspension guy by myself and I also do my own setup and basic maintainance. But your channel is great for learning stuff. Keep on going, it gives me hope in KZbin again besides all the crap you find about suspension!

[@theohlinsguy4649]

Wow, thanks!! I try really hard not to talk about stuff I actually don't know about. I learn new things every day

[@Ben-cb7uq]

Thank you a lot, Douglas! I am just starting to understand suspensions and your videos helped a lot. I come from the motorcycle world, but rather from the convenient, than the competitive side. My questions are, however, rather general. How can you say looking at a graph, that this shock with this setting will work for the intended purpose? What are you aiming for, when revalving? What could be the difference between road use and track-oriented use? Or you mainly try to correct anomalies? I would really like to see another video from you, they are of such a good quality.

[@theohlinsguy4649]

Hi Ben. Actually some great questions. As for intended purpose, I only have some experience with vehicles that need mechanical grip. When you get into cars with high downforce made from the underside of the vehicle at some point downforce is more important than mechanical grip. At that point the shock is used for keeping the aero in place. I see many "experts" talk about using shocks in mechanical grip cars to keep the "platform" in a certain position. This is not the job of the shock. When this is done you are giving up grip. There are other ways to do this. There is really no difference between motorcycle and auto damping. Also there is no difference between street and track. Grip is grip. Soft is fast. Shocks put out resistance to motion relative to shaft speed so on the track you just get more damping because the shocks/forks are moving faster. Proper compression damping bleeds off extra energy that would have been stored in the spring so you don't need a heavy spring. Enough compression damping is essential and most shocks I see don't have enough. All I want to know is what is the motion ratio so I know what the tire thinks the damping/spring rate is. I only use linear damping. Most vehicles like very similar damping at the wheel. The great question is correcting anomalies. If you are valving for anomalies like hitting a big bump etc. then you are compromising the other 99% of your grip for 1%. Anomalies are just that and I ignore them in my valving.

[@simonadams4807]

Fascinating stuff. I come from a mountain bike background where there is a lot of marketing fluff about suspension and it is hard to know what and how to adjust on my suspension. Could you do a video looking at some common mountain bike shocks?

[@theohlinsguy4649]

Hi Simon. I don't know about mountain bike suspension but I am sure there is a lot of marketing fluff out there. I only do Ohlins motorcyclde and auto so I don't have access to any of the mountain bike products. Ohlins didn't want me to do them and if they did I would need a whole new set of tools. Sorry that I can't help

[@joshuacraven6206]

F x V is one of the more powerful graphs, if you learn how to read it. It can easily show you fade/lag characteristics and even cavitation, if you're playing with gas pressures.

[@theohlinsguy4649]

You can hear cavitation on the dyno too. You can also see it clearly on the graph. I am doing a lot of TTXs where cavitation is not a problem.

[@stefans.8672]

Your dyno is not obsolete, only the shock6 software aged badly. At least part of the Roehrig guys basically skipped the MTS boat and opened up CTW automation. They have a improved software suite that is a vast stepup from shock 6. It takes a lot of time out of your dyno work once you put in the effort to adapt to this software. CTW did breath a lot more life into my Roehrig 3VS machine. Best regards, Stefan

[@theohlinsguy4649]

Hi Stefan. I don't think my dyno is at all obsolete. The software works fine. I am sorry I gave that impression. It does everything I need. The trouble with my Roehrig is that MTS has virtually no customer service when it comes to the dyno. If I need to get another dyno I probably would go to CTW. They all decided to start their own business when Roehrig was sold to MTS. It is a shame because customer service was great at Roehrig. Thanks for the comment!!

[@stefans.8672]

@@theohlinsguy4649 Obsolete way maybe to strong a word. Sorry, not a native speaker. The complete lack of customer service was what brought me to CTW. MTS did nothing but increase prices by 100% and reduce service to 0%. CTW takes great care of old Roehrig machines and the new software has its advantages. They even operate out of the old Roehrig building. You can stick with shock 6 until your computer dies of old age. Had great trouble getting shock 6 to work on a newer PC so keep the CTW guys in mind, they can keep you dyno running even when the shock 6 software stards acting up. The shock 6 software has not been updated since, I think, 2014 and it becomes a problem when you try to run it on a newer PC.

[@theohlinsguy4649]

@@stefans.8672 thanks again Stefan! I couldn't even find the shock dyno's on the MTS site. I didn't know that I could get service on my machine from CTW. I have had my Dyno for maybe 15 years without a problem so fingers crossed!

[@bsujantob]

Doug... how do you dyno forks when left fork does the compression and right fork does the rebound?

[@theohlinsguy4649]

If you are dynoing they together the graph will not know that there are 2 forks. So you just treat it as one unit and adjust compression and rebound as you would if it was a shock.

[@henrikforsberg683]

@@theohlinsguy4649 so then you have to make some kind of fixture to hold both fork legs in the dyno at the same time? 🤔 just found your channel, really interesting! Thanks a lot for doing this!

[@Gemini_0815]

At Minute 18:50 you’re showing the oscilloscopic graph for a given amplitude and frequency. I wonder if you could see the difference between a solid shim and the equivalent stack of 8 half-as-thick shims on that graph, if you’re trying various amplitudes and frequencies. I’m trying to figure this out since I saw your video about shim stacks...

[@theohlinsguy4649]

Hi Vi I don't use that graph or really understand exactly how to read it. My software can show me that graph. I was just showing it on the video because I thought it was interesting to see how things have progressed.

[@RaulBecerra2]

I'm hooked on your videos, suspension has always been a huge curiosity for me and so important to racing of all types. I have a question regarding the Ohlins Electronic dampers that came with my 2019 Ducati V4S. What are your thoughts on this system. I understand Ohlins and Ducati through continued development have improved the algorithms over the recent years to improve rider modes and other features. Everyone on the track however seems to frown upon their use and go on about using a fixed set up. I'm having good success with mine and plan to continue using them. Any thoughts on dynamic suspensions? Can you delve into some of the particulars of this kind of electronic damping variation? Looking forward to hear from our Ohlins Jedi Master? -raul

[@theohlinsguy4649]

Hi Raul. I am not a Jedi or Guru but I have opinions. I don't really like the electronic suspension when you let it change damping as you are riding. The ones I have worked on just have a stepper motor to change the bleed. Once the damping is good you should never have to change it. It is self regulating depending on shaft velocity. You can just set your damping "clicks" with the electronic system which is handy when you are trying to find a setting that works for you. Thanks for watching and I hope it has been interesting.

[@nobbytrussin]

When people talk about revalving to match different spring rates, how would you do that on a dyno? Do you set dyno force to be that of the spring rate you intend to use?

[@theohlinsguy4649]

I don't believe there is any reason to revalve for spring rate. One has nothing to do with the other in my opinion

[@nobbytrussin]

That’s really interesting as the conventional (internet) wisdom is that you have to revalve for spring changes. That being the case , when _would_ I need a revalve? If the adjusters aren’t able to give me the range of damping I need?

[@theohlinsguy4649]

Yes, conventional wisdom is often wrong. Ask one of these people why you need to change damping and how would you change it. I am guessing they all want stiffer springs. Conventional wisdom strikes again! Once you have the damping and springs that work you never have to change them. You don't need different damping and springs for on and off the track or for different tracks. Grip is grip. If you find you need more or less damping initially you can easily valve a bit more or less and try again. My video on clamping shims shows one way to do it.@@nobbytrussin

[@hiroprotagonist674]

Hi. Love your channel. Binge watching on my weekend. Are there two different 0 values on the graph because the piston is going in a loop?

[@theohlinsguy4649]

Hi Hiro. I am not sure what you are looking at. If you are seeing that when the velocity is at 0 but the lines merge above or below the 0 force it is usually because there is a difference between the compression and rebound values. I think there is just extra pressure on the higher force side and it can't get rid of that pressure before the shock changes direction. That pressure could be from very restricted or on way bleeds. Let me know if that is what you were asking... Thanks for watching

[@hiroprotagonist674]

@@theohlinsguy4649 This is a great answer. Thanks for your consideration

[@vandieman26]

Another great video !!

[@douglas_martins]

What a class!!! Master!!!!

[@theohlinsguy4649]

Thanks Douglas! Hope it was kind of clear. Trying my best!!

[@alfs8]

Do you reckon the twin-tube will be inherently prone to have hysteresis than a mono-tube damper?

[@theohlinsguy4649]

Actually quite the opposite. First you have to realize that a Ohlins twin tube is nothing like an old fashioned twin tube shock with a foot valve. A single tube shock is very susceptible to hysteresis if the bleeds are closed down or they are not carefully pressure balanced. They are actually only good in a very narrow range of adjustment. TTXs don't need to be pressure balanced and have very little change in hysteresis with adjustment (bleed) changes and also from their ability to run lower nitrogen pressure. Also there is no worry about cavitation.

[@alfs8]

@@theohlinsguy4649 Thx, I c.

[@ildkild]

I have a question... If you have a duble piston shock like on ktm enduro bikes without linkage, how would you dyno those? would`nt curve be different when the shock reaches the top cone and the second piston starts to "kick in" . in that case do you dyno the shock in different depth of stroke and would a normal shock show any differance from dynoing from different depths?

[@theohlinsguy4649]

Hi That Guy. I am assuming you are talking about a hydraulic bump stop type of thing where a second piston contacts a tapered cup at almost full bump (there is actually an Ohlins rally shock called TPX that has 2 pistons + a bump stop piston). Probably if I were dynoing it and was trying to valve the second piston I would just run the last part of the compression stroke. I don't think that dynoing at different depths would show much difference. I don't dyno with a spring on and the hookup on the dyno manipulates the shock in a pretty straight line. But in the vehicle with any shock that doesn't have a through shaft it is good to have the piston live as far down in the shock as possible. Check out my video "inside the TTX40. kzbin.info/www/bejne/bGbPla13nL-bqs0. It explains my reasons for this. Thanks for commenting and watching!!!!

[@c_laer7097]

Hi Mr Brenner, thanks for the videos. I have a question. Should I run away if I see a suspension tuner running a shock test, up to the bumper (and sometimes far beyond)? I've even seen guys doing that in high speed scenarios, horrible thing to watch and hear. Feels anti-mechanical. I don't get the purpose of this, once it has reached the bumper, damping becomes ruled by the hardness of the bumper, not hydraulics... so what's the point? I know it's possible to measure it for data acquisition on its own etc (kzbin.info/www/bejne/bILRl6umebVjptk), but dynoing it? Please englighten me, I'm either missing something or I've seen crazy things... Subsidiary question: Why do we never see suspension dyno sheets with speed above ~15 inch/sec (0.4m/sec) does it become irrelevant at some point? I know high speed are a big thing in rally, rally raid, enduro but still I never see graphs with speed above that. Thanks for the great content!

[@theohlinsguy4649]

I don't know why the do that either! One is damping and one is spring rate. Also I never run bump rubbers. My dyno only goes to 11 inches a second. I only do linear damping so it is easy to project what the damping might be at higher speeds. I concentrate on low speed because that is where the grip is. I don't think there is really high speed rebound as that speed just depends on the energy stored in the spring. As far as high speed compression goes I don't worry about it because if the shaft sees a really high velocity in the vehicles I am involved with it is usually just an anomaly and if you start damping for them you are way overdamped. A few years back I did some work for a Global Rallycross team with really cool Ohlins TPX shocks which unfortunately were spec shocks valved by someone what in my opinion didn't know what they were doing. Also this person did not have a shock dyno. The TPXs have really sophisticated hydraulic bump stops. They were alway bending shafts. They were so initially overdamped that when the shaft saw really high velocities on landing the shaft never got to high speed because it stopped moving right away as it couldn't get past the low speed damping. You don't magically get to high speed damping. You have to go through low speed first (and back through it on slow down). The shock never even got to the hydraulic stop.

[@c_laer7097]

@@theohlinsguy4649 thanks for you reply, all makes sense, nice story with the rally team!

[@RileyMcConaughey]

Do you often need to replace the brass pins?

[@theohlinsguy4649]

Not really. I have a bunch of different lengths I made but they don't seem to wear out.

[@nathanshaw3513]

Do you know what inner cartridge tool is reqired for 1996 zx9r?? Need to remove the open cartridge but can not find the correct tool.

[@theohlinsguy4649]

Do you have the part# of the Ohlins cartridge you have? If not look down inside and tell me if the top of the cartridge has 4 or 8 slots. There are a number of tools but if I have the part# maybe I can find the installation instructions which usually has a list of tools needed.

[@nathanshaw3513]

@@theohlinsguy4649 sorry it's a standard open cartridge, no ohlins parts. But I want to remove the standard to upgrade. I'd upload a photo but it wont let me

[@eerr-m1k]

The graph on 12:47 would be easier to understand if people could see any illustration regarding shock shaft position 😕 I am quite educated person but still I don't imagine what shock position is at any given velocity moment since velocity is function of distance and time. Anyway how I understand is like this: - on compression shaft positions: start [0.00; 10], middle of the stroke [9.99; 205], end of the stroke [-10; 0.00] - on rebound shaft positions: start [-10; 0.00], middle of the stroke [9.99; -160], end of the stroke [0.00; 10] Of course this "middle of the stroke" does not mean that it is exactly middle of travel distance. For example if travel distance is 2 inches so depending on valving on 5 in/sec speed it can be on 1 inch of travel or 0.5 inch of travel. I hope is is possible to understand what I have in my mind 😀

[@theohlinsguy4649]

Basically shock position with what we are talking about has nothing to do with damping. Where the shaft is doesn't matter, just the velocity that the shaft is seeing.

[@stephenpavlov8942]

Do you have any issues rebuilding/revalving the older st44 shocks? Are parts still available for them?

[@theohlinsguy4649]

Hi Stephen. ST44s are great shocks and I have all of the parts to service and revalve them. Contact me on my email [e-mail]

[@Kyle_da_athlete]

thanks very much. This helped with my assignment

[@theohlinsguy4649]

Great! Thanks for watching....

[@neelg6911]

OMG, Madoff has a brother?!!

[@theohlinsguy4649]

I didn't know he did shocks!

[@conservative-proud]

I’m not sure what you are trying to achieve... ?

[@theohlinsguy4649]

Is that a trick question?