Good stuff. Didn’t know you were local.(Simi). I’ll have to give you a call when I need something. I would like to try MX forks and shocks from Ohlins.
I have watched almost every video that you have posted and I have to say I highly appreciate all this information, making me understand more in depth how it works. I can now go ahead and start making my own changes to the suspension of my dirt bike, I will be starting off with changing the clamping shim to a slightly larger one on the rebound on the rear due to it being a little too fast! You always seem always aim for the most linear curve of damping in relation to shaft speed and I do understand why. But I would also be very interested in seeing a video where you try different shapes of stacks to see how they will look on the dyno. I also would be really interested to see how stacks with crossovers in them look on paper, for instance a smaller crossover shim in the compression stack making the shims closest to the piston "low speed" and the shims on the other side of the crossover the "high speed" compression stack. Sometimes it's good to show how to do something bad, to be able to display clearly how to do it well, I want to see some "bad" shim stacks being tested!
Hi Martin Somehow I missed your comment. Sorry! That would, for me , be a digressive stack with digressive pistons etc. Ill keep that in mind! Thanks!!!
Hi Martin. Be sure when you put a larger clamping shim on that it is not protruding into the port. I think it is really great that you are going to learn to make your own changes. As far as the rebound goes, the better option, at least initially, is to put in more compression damping. That will dissipate some of the energy stored in the spring which will also slow down the rebound as less energy will be stored in the spring. I think in one of the videos I showed the effect of a crossover shim. It usually just makes less damping which would be better to do with a uninterrupted shim stack. A crossover shim is handy when you just can't get rid of high speed or want more low speed relative to high speed. They are not bad things when used for the right reasons. I don't think that shim stacks are usually ever really bad. Mostly it is the digressive piston, closed bleed or the ratio between compression and rebound damping that isn't good (just my opinion).
I will make sure it does not protrude. Good tip on the compression and storing energy that helped me out when riding today! Thank you for the response and I will be looking forward to new videos from you.
I really love your videos. Not many people show actual suspension dynos to precisely explain the differences in shim stacks. As a data guy myself, i like to see the data! So thank you. Please make more videos! I'm working on doing my own valving on my motocross bikes, and shim stacks are a bit more complex in dirtbikes than on street/road racing applications. In motocross applications, digressive damping curves are much more preferred so the suspension stays held up in the stroke, ready for the next obstacle. So you tend to see a lot of "multi stage" stacks using crossover shims; dual stage stages are common, 3 stage as less common but are still used.
I still don't believe there is any use for digressive damping especially in something like motocross. Also you can see on the dyno sheet that all "stages" do is decrease damping. You can't see any delay from one stage to another. It is really great that you are doing your own valving!! Nothing is easy and the more you try things the faster you will get. Don't hesitate to try something that you don't think will work. Every once in a while you will get a surprise. I find many things are counter-intuitive
*You can watch this that does a much better job of explaining multi-stage stacks and exactly how to adjust them: th-cam.com/video/dRekn0iRiRs/w-d-xo.html One thing that really helps understanding is thinking of each corner as a fulcrum for the preceding layer, but as the force increases that starts to bend the next layer and so on, until you are down to a clamp and then hitting the layer after that. Some critical observations of this series: (note, I did learn some things, so I'm glad it exists, but it isn't without some problems) While I've learned a bit from The Ohlins Guy's series, like former bosses, he carries a bit of old timey "I've done this and figured it out once, so that's the only right way" mentality. Didn't matter if I could show my boss 3 better ways to do something, his way was right in his mind, so other people's ideas "couldn't work" or his favorite - were "always less right." Life lesson is to take every person's opinion with healthy grains of salt. He may be very good at doing it his way. And experience counts for a lot, but when an entire industry moves on... There is a reason modern high end dirt bike suspensions no longer follow that old conventional wisdom. And he talks down on really common upgrades (racetech) that are well substantiated as significant upgrades for a fraction of the cost. I've helped a friend tune them on his bike, and _I'd definitely consider_ them as a viable option on my bikes. If you can get most of the improvement for 1/3 of the cost, that isn't a gimmick, it's a good design that sells well for a reason. And _every_ (non-china) company uses additives in their oil. Ohlins isn't special in this regard, so they just sound dishonest every time he claims it's better than all the others because _they_ use additives - as if other's don't. Don't link to a technical marketing sheet that amount to "we put stuff in it." Quit complaining about color and show us a double blind independent test between a bunch of the oils and prove your claims. Or show us a pile of failures inordinately proportional vs yours. Do you actually have any comparative data to show a higher failure rate with yours vs any of your _several_ competitors oils? Or do you just hate the color and always go with the Ohlins sticker? And just like he can tune shim stacks, you can on those other too. And just because he doesn't understand how to tune multi-stacks well, because he avoids them, doesn't mean other companies that specialize in them or you can't easily learn the concept and alter them too. (see video linked above) And while he always says he can't, other companies seem quite capable of giving general answers and rough baselines - because they've done so many different bikes and conditions that they have a data map. No need to reinvent the wheel as a custom new concept every time. Many of them even offer it free on their websites so they don't have to waste custom fine tuning time with getting your average person in the ballpark. And a major part of digressive damping is to correct the lack of damping down low (a systemic problem at low velocity), hence needing to digress and transition not overdamping through the whole range. Linear doesn't do that. And dirt and street suspension setups are very different, you can tell even a quick glance street bikes and dirt bikes weren't even designed with the same end in mind. Most principals carry over, but condition and riding technique are very different. If you tune a bike nicely for street then you will have springs (displacement reactive) to handle things like sustained high braking (which comp damping does not continue to resist). But that same spring setup for heavy braking will be woefully inadequate to handle landing from a high jump where comp damping is king. They are almost competingly opposite scenarios. So when he makes statements in this series about 1 setup should be good for both street and offroad, it doesn't build confidence in trusting his opinion. It sounds more like my old boss with 1 answer for everything. (you can compromise to something acceptable, but refined for 1 is refined away for the other) And also most bikes have rear setups that are progressive in nature, even if directly mounted to the swingarm/no linkage (look at the angles, as the rear collapses, the shock gets closer to the ideal 90deg, improving a component of mechanical advantage/less disadvantage). *So even with a linear spring/single rate spring, they are progressive.* And when they use a linkage, they don't convert it back to linear, they make it more progressive.
Thanks for your video's you are a great teacher! I'm always learning something new here. I see similar shim stacks on the stock BMW R1200GS WP shocks one with the ring preload shim in the middle of the stack.
Hi Doug, Thank you for taking the time to make these videos. The combination of seeing the shim stack being put together and the effect of changes to that stack on the Dyno really help it all make sense. I'm planning to use what I've learned here to help tune a bicycle fork. It uses a ring shim right being the sealing shim and a clamping shim a little further up in the middle of the stack. Neither seemed to make much sense. They also use a 3 position preload to offer a lock out. I never use the lockout (or the middle setting). It makes me think that the compression stack must be over damped to achieve that lockout. Based on what I've learned from these videos, I think I'd be happy experimenting with the damper to see if I can improve things. Trouble is, I don't have access to a Dyno so it's a combination of tune by feel and a little device called a shockwiz that monitors changes in the air spring during use to give tuning recommendations.
Thanks for your comment Steve. Tuning by feel (or the stopwatch) is the only real way to do it so you are on the right track. The advantages of the dyno are to make sure that the shock is functioning properly and to see what you have actually done when you have made progress. Having a dyno is not a shortcut to performance. It might speed things up a bit though. You have to put in the work and it sounds like you are willing to do that. Since I am not really familiar with bicycle shocks I don't know what lockout is. I also am not familiar with the effects of air springs. The small shim up in the middle of the stack usually helps flatten out the damping at a some velocity depending on where you put it. What it does is separate two shims with a space so that the shim above the separation doesn't start moving until the shim below traverses the space and contacts it. I show the effect of this in my Valving #4 video about 5 minutes in. The reason I show the dyno results on my videos after making a change is that I got tired of people on TH-cam making these subjective statements about what changes in valving and adjustment do and showing fancy white board drawings to back it up. If they do show a dyno graph they usually use an average force vs absolute velocity graph instead a force vs absolute velocity one. The average graph leaves out most of the important information on the dampers performance.
@@theohlinsguy4649 The lockout feature is to stop the forks from diving under bodyweight bobbing around on long smooth climbs where you might be out of the saddle and making a huge difference to the weight bias of the complete system. It's normally achieved by adding heavily to the compression circuit. So that closing the bleed causes the fork to feel locked, the shim stack needs to be pretty stiff as well. Feels like this might be a compromise too far. I'd rather sacrifice the lockout and have a more active fork. If I'm paying for it, I want to use it
@@steveedwards5280 Interesting! One of my tenants of damping is to first find out what you want the damper to do which varies with application. Most of what I do is related to mechanical grip. What you are doing is a bit different. In my videos I am trying to show how a damper reacts to changes. Hopefully you can use this info to improve your specific application.
Its incredible the amount of info thanks a lot for taking the time to teach us all of this, i would like to see a video on that thing that we all want "progressive damping"
Hi. Thanks for watching and your comments. I see a bit of progressive damping and I would much prefer some progressiveness to digressive damping but I still think that linear is the way to go. I guess hydraulic bump stops are a form of progressive damping but really is more of a position sensitive thing as the damping only goes up relative to position of the shaft and not velocity. As I said in my spring video I am not really fond of progressive springs. I see you are in the air a lot and if I do that in my race car I have done something terribly wrong! I don't really do a lot of motocross or rally stuff so I can't really give any advice (I try to know what I don't know). That being said, my mentor Bruce Burness did do motocross (DeCoster Etc.) and I think that linear was what he was using. That doesn't mean you shouldn't give it a try. Nothing ventured, nothing gained!
@@theohlinsguy4649 yeah of course I will try, is just that we dont get our hands on shock dyno so seeing you do mods and then test them its really gold information, the nascar piston wow blow my mind, damn everytime i see a video of you blows my mind, i dont like progressive spring too but theres something with ohlins on rear shocks for motocross bikes they use some kind of progressive because first coil of rear shock is always smaller "the bee tail" some kind like that, well i wont make you waste any more time, bye!
@@Pereke69 Just try putting thicker shims up in the stack and see if you can feel the difference. You could also put thinner shims low in the stack but I would opt for the thicker ones up in the stack to begin with. That should get some more progressive damping.
Hallo and thanks for sharing your knowledge in these videos! I wanted to ask if you could explain and maybe make a video of dyno tests on the KARLOFF test shock to demonstrate the influence of rod position in the shock versus force with constant test velocity. For example, a tests series using constant 1, 2, 4, 6, 9 in/mm vecolities using whole stroke length of the shock to see how the force changes with regards to rod position in the shock at a given velocity. I'm not sure that it has 100% applicability to real world scenarios (I'm interested in motorcycle off-road racing like MX, enduro, rally, etc.), but I'd be really interesting to see how a shock works while being brought thourgh its stroke at a slow velocity compared to a fast one (with the same shimstack, bleeed clicker position, etc), esentially to understand the influence on the shim stack/bleed on the rod position in the shock depending on the rod velocity. I hope I made my idea clear and there is something interesting that you could show/teach us. Thanks again!
Unless the shock has some sort of bypass mechanism in the body there should be no difference in damping forces based on shaft location. It is only sensitive to velocity
Thanks for answering this. Is there any way you could post a link in this comment to a picture or a video where such a shock body is shown (seen), so I could understnad how those types of bypasses look and thus, hopefully, be able to determin what type of a shock I'm looking at if I ever see something similar in future? Thanks!
I don't think unsprung weight has anything to do with it. I have some dyno sheets from an early 2000s NASCAR championship winning car and the damping for road courses is pretty identical to my 1000lb formula car. The only time that I think digressive damping is "good" is for aggressive hold down/up shocks. I don't get into these applications. I am looking for mechanical grip.
At around 6:00 I say that doing this is "a nice option". Using this option all the time and selling separated shim stacks as "low, medium and high speed" is what I don't believe is correct. You don't see this in every single Ohlins shock. It is only used to get a certain outcome from time to time
Hi Brian Shock hysteresis is a difference in force in compression and/or rebound from when the shaft is speeding up to when it is slowing down. I think I show the differences on the dyno sheet in my "shock dyno basics" video. As the shock shaft is speeding up pressure builds up in the shock. As the shaft slows down to reciprocate the pressure shows up as extra force at the same velocities. Pressure can dissipate through the bleed circuit so the more closed you have your bleeds the more hysteresis you get for any given valving. Also some of the difference is caused by the nitrogen pressure in the shock . I don't think this is actual hysteresis but it might have the same effect. Trying to minimize this by lowering nitrogen pressure below the amount needed isn't a good idea as you will encounter other functional issues that are much worse.
isnt it so - that one would want digressive damping on an application where you have massive wheel travel available and You want to keep off the "seasickness". so after the initial soft side is overcome the valving is not too abrupt for high energy impacts - like hitting a sharp edge vs slow vawes of whoops.
@@theohlinsguy4649 watched all the videos. a lot of interesting info. thanks for that. we are still waiting for our dyno to be delivered - but a lot of misleading info is being flopped around the net for all of it.
@@Snowhite808 Good choice. You can't really know what you are doing without a dyno. Just remember that it doesn't tell you what is better or worse. It is also very good at seeing if you have any problem in the shock. Good luck!
Hi Thomas Thanks for watching my TH-cam channel. I only use the Ohlins oil that is specified on the spec sheet for the specific Ohlins damper I am working on. Basically I use 2 oils: Usually 1309 for motorcycle and 1304 for auto. There is a 105 oil but I just use 1309 because it is the same basic spec but updated. There are also Ohlins oils for things like snowmobiles and such that I rarely do but if I do I just order some of the correct oil. If you are in a severe climate there might be other Ohlins oils. If you have Ohlins dampers only use Ohlins oil!!! I see people on TH-cam using different weight oils in an effort to alter damping. I think this is incorrect and is just a ameture way to try to alter damping and would certainly adversely effect the function of the damper. This is not the function of oil. For that you need to adjust bleed or revalve Ohlins has a paper on "why Ohlins oil" but I can't figure out how to link it here. Ill try to find a way. If you send me an email at theohlinsguy@gmail.com I will send you a copy I hope this answers your question. I really don’t know enough about oil to do a video. I am trying not to talk about things I actually don’t know much about…………..Thanks again! Douglas
I had a thought while watching this. In a previous video you mention a piston with a smooth surface will cause a surface tension to the sealing shim. Now, on one of those dished pistons, if the dished portion has a smooth finish, could this cause a blister in the graph or maybe even adding to the resistance of opening that the preloading is creating? Maybe you've never tested this but in theory what do you think would happen if anything? Clearly the ohlins piston would not have surface tension with its ring design.
Hi Eric The shims sticking is a very rare event and would be hard to duplicate with any consistency. I would think that if the shim was preloaded it might be less likely to stick as the forces acting to open the shim might be enough to override the sticking. Good question.
@@theohlinsguy4649 ah, okay, that definitely makes sense. And good to know the sticking isn't a constant issue. You spoke briefly about thermal changes. Was wondering if you planned to cover shock oils at some point and the roll it plays?
Ohlins has a informational paper on "Why Ohlins Oil" As soon as I can figure out how to link it I will put it on. They spend a lot of time on formulating oil. The specification sheet on every Ohlins damper specifies which oil to use. I basically use Ohlins 1304 or 1309. There are other oils for specific applications like snowmobiles etc. As you can tell one of my pet peeves is when I find crap oil in Ohlins products. It is so easy to just buy the correct oil.
Would it be fair to say that road bike valve stacks are shimmed to account for potentially passengers plus luggage and that an improvement could be made to solo rider riding by reducing damping stack
Hi Phil. I don't think damping has anything to do with weight. Two different things. I only valve for motion ratio and find no difference between road or track. Best way to account for passenger and luggage would be to just add more spring preload. Thanks for the question!! Remember these are my opinions.
@@theohlinsguy4649 Thanks for the reply that makes sense . I guess find a spring that feels nice and work the adjusters around that . Great videos by the way helped me rebuild my shock just watching how you did it ✌️✌️✌️
I am glad I could help. It's not rocket science but sometimes it is good to know the details. It is mostly hard to do without the special tools. I really like it when people do it themselves. On springs, I prefer softer with more preload than stiffer. You can go too soft but once you get in the ball park it is really nice.
@@theohlinsguy4649 well I’ve worked on hydraulic rams mostly of agricultural machinery and figured that’s all it really was, just a small hydraulic ram seal piston etc . Actually being 22 years old was the worst part of stripping it, seal kit was available via a company here in the uk I touched the bore up with stones like i saw you do have the valve a rough up and just took my time. Seems perfect now slight dead spot at top out but I can work that out . Once again thanks so much for what are great educational videos .. Many thanks and blessings from Devon uk ✌️✌️✌️
is there a way to calculate shim stacks or is it all trial and error. i'm trying to learn how to manipulate snowmobile shocks depending on rider conditions and rider styles and would like to be able to figure out shim configurations based on this
Hi Leo. There might be but I wouldn't be smart enough to do that. I did give the math for calculating equivalency of multiple shims of the same diameter and thickness. I think even if you could there is a disconnect between knowing what the stack is and performance. Also what that stack is doing depends on the piston. I just have an idea from experience what shim stack to start with and then it is trial and error. I did some snowmobile shocks and had no luck at all. The show is compressible and depending on the makeup of the snow you can get completely different results. I am not a believer in changing shock settings for different track conditions and once I get a good setting I never change it. But with a snowmobile I am guessing that you would always have to change things based on snow conditions. Just a guess.
Hello I discovered all your videos and they allowed me 2 things, to learn a lot of things about suspension and also to have to review my English which I hadn't practiced since the end of the school there is ..... 35 years old...... so please excuse me for the mistakes. I ‘m not a professional but just a private person who is passionate by the suspension and who works on my son's motocross bike suspensions since 12 years now. We try different settings, we test, we change etc etc etc just based on the sensations on the track. I ‘m really interested to test the solution with a ring shim of ID 36mm OD 40mm 0.30 but do you know where I could get one because the shim sellers in France don't have this type of shim. Regards Olivier
Hi Olivier Your English is great. You speak (at least) 2 languages, I barely speak one!! Ohlins makes ring shims so there must be an Ohlins dealer in France you can get them from. Remember that you need a 36OD shim to center the ring shim. The difference between the centering shim and the ring shim denotes the amount of preload. also remember you can keep stacking ring shim sets if you need more preload. Thanks for the comment!!!!
@@theohlinsguy4649 Hello Thank you for your answer and as you tell me I will see with the OHLINS dealer in France to whom I had sent the shock absorber of the 1993 Honda 250 CR for a complete service there is 5 or 6 years. I just have one question: Can we hope one day that you will make us the same videos about the forks with internal cartridge? Thanks Olivier
@@pingping4766 Yes. I don't get them very often so next one I get I will make a video. Basically they are just a shock with separator piston put inside a fork. You also put oil in the fork but it has nothing to do with damping. Probably there for the air spring effect and cooling the part that is doing the damping
@@theohlinsguy4649 thanks. Trying to find high quality shims for my shocks. They are 16mm unfortunately. Thank you for the amazing videos, I’ve learned alot from you.
The formula is on the video. Basically divide the bigger shim by the smaller shim and multiply that to the third power. If you want to replace one .20 shim with .10 shims". .20 divided by .10 =2. 2 to the third power is 8. So it would take 8 .10 shims to equal 1 .20 shim.
@@theohlinsguy4649 if i change clamping shim only is it gonna be a precision tuning for whole stack?.. I have alot of questions if u up to explain me, i ll be thankful!
I really appreciate these videos, such fantastic info. I got to thinking about stacking shims vs using a single sealing shim and basically having the same dyno graph but stacking shims gives more mechanical grip. I notice the way the shims work is very much the same to a leaf spring. A moden parabolic leaf spring the leaves don't touch one another and require a shock absorbers to control oscillations. In the old days, leaf springs were made up using multiple leaves and often did not require shock absorbers (my background is a truck mechanic) as the friction between the leaves would sort of dapen the oscillations. In the shim stack of the shock, without multiple shims stacked together could the sealing shim be bouncing when the shock is operating at a high frequency, inhibiting its ability to meter the fluid properly. Just a thought.
Hi Isaac. I think you are really correct about the shim stack being similar to a leaf spring. I think the math might be the same. It would be very hard to get enough damping with one sealing shim. Sometimes I see stacks with only multiple sealing shims but for some reason a stack with descending diameters seems to give more grip. I don't really know why.
When a shim bends the material on the top of the shim stretched and the material on the bottom side is being compressed. There is an axis point in the middle that has no stress at all. Call it the "Neutral Axis" The further away the material is from the "Neutral Axis", the more is it stressed. Thus "Thicker" shims permanently distorts before "THINNER" shims What does this mean? THICKER Shims will distort less with less deflection. The "THINNER" Shims will distort more with more deflection. Thinner shims are used in the "Low-Speed" area of the stack because they have to deflect further than the High-Speed stack by the thickness .
Good stuff. Didn’t know you were local.(Simi). I’ll have to give you a call when I need something. I would like to try MX forks and shocks from Ohlins.
I have watched almost every video that you have posted and I have to say I highly appreciate all this information, making me understand more in depth how it works. I can now go ahead and start making my own changes to the suspension of my dirt bike, I will be starting off with changing the clamping shim to a slightly larger one on the rebound on the rear due to it being a little too fast!
You always seem always aim for the most linear curve of damping in relation to shaft speed and I do understand why. But I would also be very interested in seeing a video where you try different shapes of stacks to see how they will look on the dyno. I also would be really interested to see how stacks with crossovers in them look on paper, for instance a smaller crossover shim in the compression stack making the shims closest to the piston "low speed" and the shims on the other side of the crossover the "high speed" compression stack.
Sometimes it's good to show how to do something bad, to be able to display clearly how to do it well, I want to see some "bad" shim stacks being tested!
Hi Martin Somehow I missed your comment. Sorry! That would, for me , be a digressive stack with digressive pistons etc. Ill keep that in mind! Thanks!!!
Shimmy shimmy ya, shimmy ye, shimmy yeah!
That could be the latest new dance craze.
@@theohlinsguy4649Shocking realisation 😮
Great Great Great Great videos!!!!!!!!! I'm all but converted to Ohlins! AND I live in Western North Carolina about 1.5 hours from Ohlins factory.
Excellent! Great people in Hendersonville!!
Hi Martin. Be sure when you put a larger clamping shim on that it is not protruding into the port. I think it is really great that you are going to learn to make your own changes. As far as the rebound goes, the better option, at least initially, is to put in more compression damping. That will dissipate some of the energy stored in the spring which will also slow down the rebound as less energy will be stored in the spring.
I think in one of the videos I showed the effect of a crossover shim. It usually just makes less damping which would be better to do with a uninterrupted shim stack. A crossover shim is handy when you just can't get rid of high speed or want more low speed relative to high speed. They are not bad things when used for the right reasons.
I don't think that shim stacks are usually ever really bad. Mostly it is the digressive piston, closed bleed or the ratio between compression and rebound damping that isn't good (just my opinion).
I will make sure it does not protrude. Good tip on the compression and storing energy that helped me out when riding today!
Thank you for the response and I will be looking forward to new videos from you.
I really love your videos. Not many people show actual suspension dynos to precisely explain the differences in shim stacks. As a data guy myself, i like to see the data! So thank you. Please make more videos!
I'm working on doing my own valving on my motocross bikes, and shim stacks are a bit more complex in dirtbikes than on street/road racing applications. In motocross applications, digressive damping curves are much more preferred so the suspension stays held up in the stroke, ready for the next obstacle. So you tend to see a lot of "multi stage" stacks using crossover shims; dual stage stages are common, 3 stage as less common but are still used.
Thanks!
I still don't believe there is any use for digressive damping especially in something like motocross. Also you can see on the dyno sheet that all "stages" do is decrease damping. You can't see any delay from one stage to another. It is really great that you are doing your own valving!! Nothing is easy and the more you try things the faster you will get. Don't hesitate to try something that you don't think will work. Every once in a while you will get a surprise. I find many things are counter-intuitive
*You can watch this that does a much better job of explaining multi-stage stacks and exactly how to adjust them:
th-cam.com/video/dRekn0iRiRs/w-d-xo.html
One thing that really helps understanding is thinking of each corner as a fulcrum for the preceding layer, but as the force increases that starts to bend the next layer and so on, until you are down to a clamp and then hitting the layer after that.
Some critical observations of this series: (note, I did learn some things, so I'm glad it exists, but it isn't without some problems)
While I've learned a bit from The Ohlins Guy's series, like former bosses, he carries a bit of old timey "I've done this and figured it out once, so that's the only right way" mentality.
Didn't matter if I could show my boss 3 better ways to do something, his way was right in his mind, so other people's ideas "couldn't work" or his favorite - were "always less right." Life lesson is to take every person's opinion with healthy grains of salt.
He may be very good at doing it his way. And experience counts for a lot, but when an entire industry moves on...
There is a reason modern high end dirt bike suspensions no longer follow that old conventional wisdom. And he talks down on really common upgrades (racetech) that are well substantiated as significant upgrades for a fraction of the cost.
I've helped a friend tune them on his bike, and _I'd definitely consider_ them as a viable option on my bikes. If you can get most of the improvement for 1/3 of the cost, that isn't a gimmick, it's a good design that sells well for a reason.
And _every_ (non-china) company uses additives in their oil. Ohlins isn't special in this regard, so they just sound dishonest every time he claims it's better than all the others because _they_ use additives - as if other's don't. Don't link to a technical marketing sheet that amount to "we put stuff in it." Quit complaining about color and show us a double blind independent test between a bunch of the oils and prove your claims. Or show us a pile of failures inordinately proportional vs yours. Do you actually have any comparative data to show a higher failure rate with yours vs any of your _several_ competitors oils? Or do you just hate the color and always go with the Ohlins sticker?
And just like he can tune shim stacks, you can on those other too.
And just because he doesn't understand how to tune multi-stacks well, because he avoids them, doesn't mean other companies that specialize in them or you can't easily learn the concept and alter them too. (see video linked above)
And while he always says he can't, other companies seem quite capable of giving general answers and rough baselines - because they've done so many different bikes and conditions that they have a data map. No need to reinvent the wheel as a custom new concept every time. Many of them even offer it free on their websites so they don't have to waste custom fine tuning time with getting your average person in the ballpark.
And a major part of digressive damping is to correct the lack of damping down low (a systemic problem at low velocity), hence needing to digress and transition not overdamping through the whole range. Linear doesn't do that.
And dirt and street suspension setups are very different, you can tell even a quick glance street bikes and dirt bikes weren't even designed with the same end in mind. Most principals carry over, but condition and riding technique are very different.
If you tune a bike nicely for street then you will have springs (displacement reactive) to handle things like sustained high braking (which comp damping does not continue to resist). But that same spring setup for heavy braking will be woefully inadequate to handle landing from a high jump where comp damping is king. They are almost competingly opposite scenarios.
So when he makes statements in this series about 1 setup should be good for both street and offroad, it doesn't build confidence in trusting his opinion. It sounds more like my old boss with 1 answer for everything. (you can compromise to something acceptable, but refined for 1 is refined away for the other)
And also most bikes have rear setups that are progressive in nature, even if directly mounted to the swingarm/no linkage (look at the angles, as the rear collapses, the shock gets closer to the ideal 90deg, improving a component of mechanical advantage/less disadvantage). *So even with a linear spring/single rate spring, they are progressive.*
And when they use a linkage, they don't convert it back to linear, they make it more progressive.
At 5:10, valving in stages. ohlins does this too. look spec card YA3670, old ohlins damper for yz 250.
Thanks for your video's you are a great teacher! I'm always learning something new here.
I see similar shim stacks on the stock BMW R1200GS WP shocks one with the ring preload shim in the middle of the stack.
Thanks Luke! I am trying!! I also learn something new almost every day. Especially with Ohlins as they are always evolving.
I really love your videos. Ohlins used in past also preload pistons. The pistons had a radius of 1200 mm on the rebound site.
Thanks for watching!!
Hi Doug,
Thank you for taking the time to make these videos. The combination of seeing the shim stack being put together and the effect of changes to that stack on the Dyno really help it all make sense.
I'm planning to use what I've learned here to help tune a bicycle fork. It uses a ring shim right being the sealing shim and a clamping shim a little further up in the middle of the stack. Neither seemed to make much sense. They also use a 3 position preload to offer a lock out. I never use the lockout (or the middle setting). It makes me think that the compression stack must be over damped to achieve that lockout. Based on what I've learned from these videos, I think I'd be happy experimenting with the damper to see if I can improve things.
Trouble is, I don't have access to a Dyno so it's a combination of tune by feel and a little device called a shockwiz that monitors changes in the air spring during use to give tuning recommendations.
Thanks for your comment Steve. Tuning by feel (or the stopwatch) is the only real way to do it so you are on the right track. The advantages of the dyno are to make sure that the shock is functioning properly and to see what you have actually done when you have made progress. Having a dyno is not a shortcut to performance. It might speed things up a bit though. You have to put in the work and it sounds like you are willing to do that.
Since I am not really familiar with bicycle shocks I don't know what lockout is. I also am not familiar with the effects of air springs.
The small shim up in the middle of the stack usually helps flatten out the damping at a some velocity depending on where you put it. What it does is separate two shims with a space so that the shim above the separation doesn't start moving until the shim below traverses the space and contacts it. I show the effect of this in my Valving #4 video about 5 minutes in.
The reason I show the dyno results on my videos after making a change is that I got tired of people on TH-cam making these subjective statements about what changes in valving and adjustment do and showing fancy white board drawings to back it up. If they do show a dyno graph they usually use an average force vs absolute velocity graph instead a force vs absolute velocity one. The average graph leaves out most of the important information on the dampers performance.
@@theohlinsguy4649 The lockout feature is to stop the forks from diving under bodyweight bobbing around on long smooth climbs where you might be out of the saddle and making a huge difference to the weight bias of the complete system.
It's normally achieved by adding heavily to the compression circuit. So that closing the bleed causes the fork to feel locked, the shim stack needs to be pretty stiff as well. Feels like this might be a compromise too far. I'd rather sacrifice the lockout and have a more active fork. If I'm paying for it, I want to use it
@@steveedwards5280 Interesting! One of my tenants of damping is to first find out what you want the damper to do which varies with application. Most of what I do is related to mechanical grip. What you are doing is a bit different. In my videos I am trying to show how a damper reacts to changes. Hopefully you can use this info to improve your specific application.
Loving the instructional videos especially the shim stacks.
Its incredible the amount of info thanks a lot for taking the time to teach us all of this, i would like to see a video on that thing that we all want "progressive damping"
Hi. Thanks for watching and your comments. I see a bit of progressive damping and I would much prefer some progressiveness to digressive damping but I still think that linear is the way to go. I guess hydraulic bump stops are a form of progressive damping but really is more of a position sensitive thing as the damping only goes up relative to position of the shaft and not velocity. As I said in my spring video I am not really fond of progressive springs. I see you are in the air a lot and if I do that in my race car I have done something terribly wrong! I don't really do a lot of motocross or rally stuff so I can't really give any advice (I try to know what I don't know). That being said, my mentor Bruce Burness did do motocross (DeCoster Etc.) and I think that linear was what he was using. That doesn't mean you shouldn't give it a try. Nothing ventured, nothing gained!
@@theohlinsguy4649 yeah of course I will try, is just that we dont get our hands on shock dyno so seeing you do mods and then test them its really gold information, the nascar piston wow blow my mind, damn everytime i see a video of you blows my mind, i dont like progressive spring too but theres something with ohlins on rear shocks for motocross bikes they use some kind of progressive because first coil of rear shock is always smaller "the bee tail" some kind like that, well i wont make you waste any more time, bye!
@@Pereke69 Just try putting thicker shims up in the stack and see if you can feel the difference. You could also put thinner shims low in the stack but I would opt for the thicker ones up in the stack to begin with. That should get some more progressive damping.
Great sir I learned new things . Regarding difference about pre load normal stack .
Thanks Ejaz!
Hallo and thanks for sharing your knowledge in these videos!
I wanted to ask if you could explain and maybe make a video of dyno tests on the KARLOFF test shock to demonstrate the influence of rod position in the shock versus force with constant test velocity.
For example, a tests series using constant 1, 2, 4, 6, 9 in/mm vecolities using whole stroke length of the shock to see how the force changes with regards to rod position in the shock at a given velocity.
I'm not sure that it has 100% applicability to real world scenarios (I'm interested in motorcycle off-road racing like MX, enduro, rally, etc.), but I'd be really interesting to see how a shock works while being brought thourgh its stroke at a slow velocity compared to a fast one (with the same shimstack, bleeed clicker position, etc), esentially to understand the influence on the shim stack/bleed on the rod position in the shock depending on the rod velocity.
I hope I made my idea clear and there is something interesting that you could show/teach us.
Thanks again!
Unless the shock has some sort of bypass mechanism in the body there should be no difference in damping forces based on shaft location. It is only sensitive to velocity
Thanks for answering this. Is there any way you could post a link in this comment to a picture or a video where such a shock body is shown (seen), so I could understnad how those types of bypasses look and thus, hopefully, be able to determin what type of a shock I'm looking at if I ever see something similar in future?
Thanks!
Would digressive be better suited to situations with high unsprung weight like a trophy truck?
Thanks for so much information, you've earned my sub!
I don't think unsprung weight has anything to do with it. I have some dyno sheets from an early 2000s NASCAR championship winning car and the damping for road courses is pretty identical to my 1000lb formula car. The only time that I think digressive damping is "good" is for aggressive hold down/up shocks. I don't get into these applications. I am looking for mechanical grip.
At around 6:00 I say that doing this is "a nice option". Using this option all the time and selling separated shim stacks as "low, medium and high speed" is what I don't believe is correct. You don't see this in every single Ohlins shock. It is only used to get a certain outcome from time to time
Please explain shock hysteresis.
Hi Brian Shock hysteresis is a difference in force in compression and/or rebound from when the shaft is speeding up to when it is slowing down. I think I show the differences on the dyno sheet in my "shock dyno basics" video. As the shock shaft is speeding up pressure builds up in the shock. As the shaft slows down to reciprocate the pressure shows up as extra force at the same velocities. Pressure can dissipate through the bleed circuit so the more closed you have your bleeds the more hysteresis you get for any given valving. Also some of the difference is caused by the nitrogen pressure in the shock . I don't think this is actual hysteresis but it might have the same effect. Trying to minimize this by lowering nitrogen pressure below the amount needed isn't a good idea as you will encounter other functional issues that are much worse.
isnt it so - that one would want digressive damping on an application where you have massive wheel travel available and You want to keep off the "seasickness". so after the initial soft side is overcome the valving is not too abrupt for high energy impacts - like hitting a sharp edge vs slow vawes of whoops.
If you get a hard hit with lots of slow speed compression the whole thing locks up.
@@theohlinsguy4649 watched all the videos. a lot of interesting info. thanks for that. we are still waiting for our dyno to be delivered - but a lot of misleading info is being flopped around the net for all of it.
@@Snowhite808 Good choice. You can't really know what you are doing without a dyno. Just remember that it doesn't tell you what is better or worse. It is also very good at seeing if you have any problem in the shock. Good luck!
Can you do a video on damper oil? What is good oil and why ? etc...
Hi Thomas
Thanks for watching my TH-cam channel. I only use the Ohlins oil that is specified on the spec sheet for the specific Ohlins damper I am working on. Basically I use 2 oils: Usually 1309 for motorcycle and 1304 for auto. There is a 105 oil but I just use 1309 because it is the same basic spec but updated. There are also Ohlins oils for things like snowmobiles and such that I rarely do but if I do I just order some of the correct oil. If you are in a severe climate there might be other Ohlins oils. If you have Ohlins dampers only use Ohlins oil!!!
I see people on TH-cam using different weight oils in an effort to alter damping. I think this is incorrect and is just a ameture way to try to alter damping and would certainly adversely effect the function of the damper. This is not the function of oil. For that you need to adjust bleed or revalve
Ohlins has a paper on "why Ohlins oil" but I can't figure out how to link it here. Ill try to find a way. If you send me an email at theohlinsguy@gmail.com I will send you a copy
I hope this answers your question. I really don’t know enough about oil to do a video. I am trying not to talk about things I actually don’t know much about…………..Thanks again! Douglas
Great videos ! I just wanted to know if the Ohlins ROAD AND TRACK are revalvable ( for raod use only ) and if it is really worth ..
Yes, they are revalvable. I don't believe there is any difference in valving between road and track. Grip is grip. I think they are a great value
I had a thought while watching this. In a previous video you mention a piston with a smooth surface will cause a surface tension to the sealing shim. Now, on one of those dished pistons, if the dished portion has a smooth finish, could this cause a blister in the graph or maybe even adding to the resistance of opening that the preloading is creating? Maybe you've never tested this but in theory what do you think would happen if anything? Clearly the ohlins piston would not have surface tension with its ring design.
Hi Eric The shims sticking is a very rare event and would be hard to duplicate with any consistency. I would think that if the shim was preloaded it might be less likely to stick as the forces acting to open the shim might be enough to override the sticking. Good question.
@@theohlinsguy4649 ah, okay, that definitely makes sense. And good to know the sticking isn't a constant issue. You spoke briefly about thermal changes. Was wondering if you planned to cover shock oils at some point and the roll it plays?
Ohlins has a informational paper on "Why Ohlins Oil" As soon as I can figure out how to link it I will put it on. They spend a lot of time on formulating oil. The specification sheet on every Ohlins damper specifies which oil to use. I basically use Ohlins 1304 or 1309. There are other oils for specific applications like snowmobiles etc. As you can tell one of my pet peeves is when I find crap oil in Ohlins products. It is so easy to just buy the correct oil.
u da man all the gear and no idea, albert E RIP
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Would it be fair to say that road bike valve stacks are shimmed to account for potentially passengers plus luggage and that an improvement could be made to solo rider riding by reducing damping stack
Hi Phil. I don't think damping has anything to do with weight. Two different things. I only valve for motion ratio and find no difference between road or track. Best way to account for passenger and luggage would be to just add more spring preload. Thanks for the question!! Remember these are my opinions.
@@theohlinsguy4649 Thanks for the reply that makes sense . I guess find a spring that feels nice and work the adjusters around that . Great videos by the way helped me rebuild my shock just watching how you did it ✌️✌️✌️
I am glad I could help. It's not rocket science but sometimes it is good to know the details. It is mostly hard to do without the special tools. I really like it when people do it themselves. On springs, I prefer softer with more preload than stiffer. You can go too soft but once you get in the ball park it is really nice.
@@theohlinsguy4649 well I’ve worked on hydraulic rams mostly of agricultural machinery and figured that’s all it really was, just a small hydraulic ram seal piston etc . Actually being 22 years old was the worst part of stripping it, seal kit was available via a company here in the uk I touched the bore up with stones like i saw you do have the valve a rough up and just took my time. Seems perfect now slight dead spot at top out but I can work that out . Once again thanks so much for what are great educational videos .. Many thanks and blessings from Devon uk ✌️✌️✌️
is there a way to calculate shim stacks or is it all trial and error. i'm trying to learn how to manipulate snowmobile shocks depending on rider conditions and rider styles and would like to be able to figure out shim configurations based on this
Hi Leo. There might be but I wouldn't be smart enough to do that. I did give the math for calculating equivalency of multiple shims of the same diameter and thickness. I think even if you could there is a disconnect between knowing what the stack is and performance. Also what that stack is doing depends on the piston. I just have an idea from experience what shim stack to start with and then it is trial and error. I did some snowmobile shocks and had no luck at all. The show is compressible and depending on the makeup of the snow you can get completely different results. I am not a believer in changing shock settings for different track conditions and once I get a good setting I never change it. But with a snowmobile I am guessing that you would always have to change things based on snow conditions. Just a guess.
Is there a #5 in this series coming out anytime soon ?
I don't think so. There is not much more I know!
Hello
I discovered all your videos and they allowed me 2 things, to learn a lot of things about suspension and also to have to review my English which I hadn't practiced since the end of the school there is ..... 35 years old...... so please excuse me for the mistakes.
I ‘m not a professional but just a private person who is passionate by the suspension and who works on my son's motocross bike suspensions since 12 years now.
We try different settings, we test, we change etc etc etc just based on the sensations on the track.
I ‘m really interested to test the solution with a ring shim of ID 36mm OD 40mm 0.30 but do you know where I could get one because the shim sellers in France don't have this type of shim.
Regards Olivier
Hi Olivier Your English is great. You speak (at least) 2 languages, I barely speak one!! Ohlins makes ring shims so there must be an Ohlins dealer in France you can get them from. Remember that you need a 36OD shim to center the ring shim. The difference between the centering shim and the ring shim denotes the amount of preload. also remember you can keep stacking ring shim sets if you need more preload. Thanks for the comment!!!!
@@theohlinsguy4649 Hello
Thank you for your answer and as you tell me I will see with the OHLINS dealer in France to whom I had sent the shock absorber of the 1993 Honda 250 CR for a complete service there is 5 or 6 years.
I just have one question:
Can we hope one day that you will make us the same videos about the forks with internal cartridge?
Thanks Olivier
@@pingping4766 Yes. I don't get them very often so next one I get I will make a video. Basically they are just a shock with separator piston put inside a fork. You also put oil in the fork but it has nothing to do with damping. Probably there for the air spring effect and cooling the part that is doing the damping
What is the I.D. Of Ohlins shims?
Hi. There are 3 IDs that I know of. Shims for single tube shocks are 12mm, fork shims are 8mm and TTX shims are 6mm
@@theohlinsguy4649 thanks. Trying to find high quality shims for my shocks. They are 16mm unfortunately. Thank you for the amazing videos, I’ve learned alot from you.
hello sir....how to buy SIM piston..?do you like it?
Hi Ikrom. Sorry, what is a SIM piston?
SIM compression and riboun tuan
Nice sir
Hello, how are you calculated the amount of thinner or thicker shims to replace?
The formula is on the video. Basically divide the bigger shim by the smaller shim and multiply that to the third power. If you want to replace one .20 shim with .10 shims". .20 divided by .10 =2. 2 to the third power is 8. So it would take 8 .10 shims to equal 1 .20 shim.
@@theohlinsguy4649 what if i want to make the opposite thing? And arent 8 shims stiffer than 1?
@@theohlinsguy4649 if i change clamping shim only is it gonna be a precision tuning for whole stack?.. I have alot of questions if u up to explain me, i ll be thankful!
@@zlatomirkolev9762 It is pretty interesting that it takes 8 shims that are half as thick to make one shim twice as thick but that is true.
@@zlatomirkolev9762 Watch my video on clamping shimw. Yes, it is kind of fine tuning
I really appreciate these videos, such fantastic info.
I got to thinking about stacking shims vs using a single sealing shim and basically having the same dyno graph but stacking shims gives more mechanical grip. I notice the way the shims work is very much the same to a leaf spring. A moden parabolic leaf spring the leaves don't touch one another and require a shock absorbers to control oscillations. In the old days, leaf springs were made up using multiple leaves and often did not require shock absorbers (my background is a truck mechanic) as the friction between the leaves would sort of dapen the oscillations. In the shim stack of the shock, without multiple shims stacked together could the sealing shim be bouncing when the shock is operating at a high frequency, inhibiting its ability to meter the fluid properly. Just a thought.
Hi Isaac. I think you are really correct about the shim stack being similar to a leaf spring. I think the math might be the same. It would be very hard to get enough damping with one sealing shim. Sometimes I see stacks with only multiple sealing shims but for some reason a stack with descending diameters seems to give more grip. I don't really know why.
When a shim bends the material on the top of the shim stretched and the material on the bottom side is being compressed. There is an axis point in the middle that has no stress at all. Call it the "Neutral Axis" The further away the material is from the "Neutral Axis", the more is it stressed. Thus "Thicker" shims permanently distorts before "THINNER" shims
What does this mean? THICKER Shims will distort less with less deflection. The "THINNER" Shims will distort more with more deflection. Thinner shims are used in the "Low-Speed" area of the stack because they have to deflect further than the High-Speed stack by the thickness .
wat a flog
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