Thank you ! This is a great video! There is only one thing that remains a mystery how much damping force do you actually need to make it exceptional or what would be the golden rule of thumb when it comes to valving.
Good question but I really don't have an answer. When these things are quantified they are usually not so good. You just have to try different settings. You want as little damping as you can live with in my opinion
*That's very situation dependent* (not an avoidance non-answer). *And are you talking compression or rebound?* (2 very different things) Some examples: MX bike taking a big jump: Springs alone will not be enough to stop that (or they'd be way too stiff for the rest of the course). And springs are displacement based, so *they'd kick in with more force too late in the travel.* Still better than bottoming to a collision stop, so it's like being glad you got punched with a boxing glove vs bare fist... *Compression damping (velocity based force) is a better solution* to stop from slamming on the landing. How much do you need? Depends on the jump height, the landing (transition or landing on the flat), rider & bike weights, springs installed, tires & inflation, and even whether you are landing on deep loose dirt vs blue or hard pack. You could calculate all this in advance ideal for a single jump, or *set it generally with some margins for error,* or put some bump stops in and eat it on that one jump for the sake of settings better elsewhere. Trail bike on mostly smooth surface with an occasional bump: for max ride comfort/cush, use a higher rebound damping closer to the crossover between under/over damped (still want it less than that so the tire can follow dips fast enough to keep traction and not allow the bike frame to dive) Trail bike on a gravel washboard or rapid woops: if hitting them fast enough, that same comfort rebound damping would not allow the suspension to recover fast enough, therefore *the faster rider would need less rebound damping to avoid packing,* which would make the rear get rapidly stiffer and mess with geometry as it squats. (watch particularly older MX racing over whoops and see when they tend to lose control...squat, squat, squat, slam, tipped forward, front end slam, kiss the dirt) Trail bike with way too low rebound damping in the rear with a bit soft suspension (eg wr250r): *deceptively ok.* Feels mostly fine, "hey, not bad for factory suspension"...until you happen to hit some bumps/whoops wrong and have the rear suspension squished down at the same time your butt happens to hit the seat. From feeling fine, out of no where, the *lack of rebound makes the bike judo throw you* (which if you've ever done, you realize it is very easy/little force to throw someone over you, and they can't stop it once you've done the little launch initiation).
For a front wheel for a typical passenger car, With shock directly attached to the hub for a car and the hub rotates around the shock as car steers, wouldn't that always be 1:1 ratio?
HI. No. It would depend on factors like where the shock attaches on top and where on the hub. It is actually hard to get a 1 to 1 ratio without some sort of a rocker or crank system. Some BMW cars get more than a 1 to 1 by mounting the rear shock in back of the axle. I personally don't like a 1 to 1 as it is very easy to overdamp and hard to find soft enough springs. A lot of people have all kinds of reasons to do a 1 to 1 but I don't believe any of them. The only good thing about it is you don't have to do any calculations for wheel rate.
Great videos. I would like more info on compression and damping rates for various conditions. How do high speed and low speed damping rates work with regards to internal bleeds and shims. No specific applications, just curious thats all.
Bleeds are basically low speed damping. They also control when the shims start to open. I think once they can no longer pass oil whatever the shims and pistons control what the damping will look like.
What to do with progressive rear linkage? forces and shock speeds change as the wheel moves in its travel. Most mountain bikes these days have this. Doesn't this make it harder to get your shock valved? The position of the rear wheel in the travel changes the behavior of the chock? I have 160 mm rear travel. the feel in the first 10mm will be different to the last 10mm as the chock will start to meve more/faster. Sorry fore the rambling.
Hi Thomas I really don't know much about bicycles. If I have to guess I would say that progressive is no good. As in Motorcycles, I am sure that someone makes a linear linkage. But maybe for some reason it works on a bicycle. I am not sure about the valving. Damping with any valving changes with velocity. I think a progressive linkage might have a different effect than a progressive spring. I will have to ponder what is going on. Sorry I can't be of more help but I don't want to make suggestions about something I don't really understand.
Is there a formula to figure valving change necessary if I move a shock from a .595 motion ratio to a .8 ratio while the spring stays at the .595? Trying to maintain the same feel, ride and handling characteristics with a different mounting location with minimal testing. Especially when using excessive low speed to control posture (for aero or mechanical grip due to control arm angle). Thanks for sharing your knowledge with us. Very helpful.
Hi Greg. I don't really have any formulas for valving. If I understand the question if you go to a .8 motion ratio you need to have less damping and a softer spring. If the spring is on the shock and you want the same wheel rate as the .595 you need a softer spring.
@The Ohlins Guy right now the spring is at .595 and the shock is at .8. Changing to a class that requires the shock to be mounted inside the spring at .595 which will reduce shock travel etc. I'm thinking it may be under dampened after relocating the shock? 🤔 kinda thinking I may need to reduce bleed and stiffen the valve stack to maintain the same feel and other handling characteristics. I'm going to get out the SAE books and try to speed up the learning curve to avoid expensive trial-and-error testing.
@The Ohlins Guy, so by method of your example using the weight/spring model with the lift, would this be comparable to a lower control arm and a spring/damper. In other words, let's say we are looking at a rear suspension set up of a bmw. Most/ if not all latest 3 series models have a divorced rear set up. Would your example be applicable to it taking less nm/ pounds per inch to move compress the spring than a true coilover setup? Sorry if my question sounds confusing, I am trying to word it correctly. Just from what I gathered I am seeing that a true rear coilover setup would take more force to compress the spring, then a divorced rear setup.
Hi Kali If I understand correctly the spring and shock are seperate. If that is so just survey each one separately. That way you can find out actual spring wheel rate and damping at the wheel. Thanks for the comment....
Motion ratio is quite interesting as it is rarely linear, especially on bikes/motorcycles. So it is great to graph this IE take measurements every cm/ half in. And then on top of that, your track width or on bikes front/rear to center changes causing quite a bit of weight distribution problems.
@@theohlinsguy4649 Not offering a solution. Just stating that things get complex quickly, more so than many think. IE our mountain bikes may increase the distance the shock travels as the wheel moves up, and this is where a digressive shock tune can come into play. With this the tuner is still attempting to make a linear feeling force as the wheel travels up and back down.
@@theohlinsguy4649 point and solution is if we are going down the suspension kinematics route here, is just make a simple model of the suspension which will generate the relative plot/equation of the shock linkage progression, which needs to be taken into account for how the progression of the forces from wheel movement needs to be compensated by the shock/spring, so the general approach if suspension is linear (fixed motion ratio), then the shock needs to have some progression built into it to resist linearity towards the end of the stroke, while if there is already a solid progression in the lineages of suspension, then the shock could be quite linear with regards to full compression, and the key is to get the HSR to match the spring force at full compression
@@ivanrybkin9384 All nice in the technical hypothetical ethers but not very useful where the rubber meets the road. Any full compression event doesn't matter. It is just an anomaly and if you start setting up for that you screw up 99.999 percent of the rest of the track. Springs that we use are linear (I would never use a progressive spring) so what would you do about that?? Perfect is the enemy of good.
For circuit racing, is a geometrical linkage that increases motion ratio (make springing/damping harder as the tires move up, a bad thing? Would there be a benefit to having an initial soft suspension for small bumps then a progressively harder (via linkage not springs), to control roll and make the car more reactive in cornering? Thanks!
Rising rate suspension was all the rage for a while in the 60's. My opinion is that anything that is not linear is not good. Using the damper to control the "platform" is not the best use. That being said I would rather see progressive damping than digressive.
Hi Marcos Are your forks Ohlins? What is the Ohlins part #? Do you want to add progressive springs? If so, watch my "everything you wanted to know about springs" to see my feeling on progressive springs. I would be happy to help if I can.
Great videos. I have learned more information from your videos in one day of watching then I have in 4 weeks of research.
Thanks Daniel! If you have any questions in the future just comment or email me theohlinsguy@gmail.com
Really loving your videos! Thank you for taking the time to share your knowledge. :)
Thanks! I'm trying!!
Thank you ! This is a great video! There is only one thing that remains a mystery how much damping force do you actually need to make it exceptional or what would be the golden rule of thumb when it comes to valving.
Good question but I really don't have an answer. When these things are quantified they are usually not so good. You just have to try different settings. You want as little damping as you can live with in my opinion
*That's very situation dependent* (not an avoidance non-answer).
*And are you talking compression or rebound?* (2 very different things)
Some examples:
MX bike taking a big jump: Springs alone will not be enough to stop that (or they'd be way too stiff for the rest of the course). And springs are displacement based, so *they'd kick in with more force too late in the travel.* Still better than bottoming to a collision stop, so it's like being glad you got punched with a boxing glove vs bare fist... *Compression damping (velocity based force) is a better solution* to stop from slamming on the landing.
How much do you need? Depends on the jump height, the landing (transition or landing on the flat), rider & bike weights, springs installed, tires & inflation, and even whether you are landing on deep loose dirt vs blue or hard pack. You could calculate all this in advance ideal for a single jump, or *set it generally with some margins for error,* or put some bump stops in and eat it on that one jump for the sake of settings better elsewhere.
Trail bike on mostly smooth surface with an occasional bump: for max ride comfort/cush, use a higher rebound damping closer to the crossover between under/over damped (still want it less than that so the tire can follow dips fast enough to keep traction and not allow the bike frame to dive)
Trail bike on a gravel washboard or rapid woops: if hitting them fast enough, that same comfort rebound damping would not allow the suspension to recover fast enough, therefore *the faster rider would need less rebound damping to avoid packing,* which would make the rear get rapidly stiffer and mess with geometry as it squats. (watch particularly older MX racing over whoops and see when they tend to lose control...squat, squat, squat, slam, tipped forward, front end slam, kiss the dirt)
Trail bike with way too low rebound damping in the rear with a bit soft suspension (eg wr250r): *deceptively ok.* Feels mostly fine, "hey, not bad for factory suspension"...until you happen to hit some bumps/whoops wrong and have the rear suspension squished down at the same time your butt happens to hit the seat. From feeling fine, out of no where, the *lack of rebound makes the bike judo throw you* (which if you've ever done, you realize it is very easy/little force to throw someone over you, and they can't stop it once you've done the little launch initiation).
For a front wheel for a typical passenger car, With shock directly attached to the hub for a car and the hub rotates around the shock as car steers, wouldn't that always be 1:1 ratio?
HI. No. It would depend on factors like where the shock attaches on top and where on the hub. It is actually hard to get a 1 to 1 ratio without some sort of a rocker or crank system. Some BMW cars get more than a 1 to 1 by mounting the rear shock in back of the axle. I personally don't like a 1 to 1 as it is very easy to overdamp and hard to find soft enough springs. A lot of people have all kinds of reasons to do a 1 to 1 but I don't believe any of them. The only good thing about it is you don't have to do any calculations for wheel rate.
Awesome video!
I am doing a 5.5:1 on my b2200 diesel.
I love my diesel truck too!! Glad it was interesting to you. It is something so basic and yet so overlooked
well done Doug glad I found your video
Thanks Greg!
Great videos. I would like more info on compression and damping rates for various conditions. How do high speed and low speed damping rates work with regards to internal bleeds and shims. No specific applications, just curious thats all.
Bleeds are basically low speed damping. They also control when the shims start to open. I think once they can no longer pass oil whatever the shims and pistons control what the damping will look like.
What to do with progressive rear linkage? forces and shock speeds change as the wheel moves in its travel. Most mountain bikes these days have this. Doesn't this make it harder to get your shock valved? The position of the rear wheel in the travel changes the behavior of the chock? I have 160 mm rear travel. the feel in the first 10mm will be different to the last 10mm as the chock will start to meve more/faster. Sorry fore the rambling.
Hi Thomas I really don't know much about bicycles. If I have to guess I would say that progressive is no good. As in Motorcycles, I am sure that someone makes a linear linkage. But maybe for some reason it works on a bicycle.
I am not sure about the valving. Damping with any valving changes with velocity. I think a progressive linkage might have a different effect than a progressive spring. I will have to ponder what is going on. Sorry I can't be of more help but I don't want to make suggestions about something I don't really understand.
Hey. Is it true that linkage in motorcycle swingarm makes ratio change depending on travel?
I don't think any suspension is totally linear. There are linkages which purposely manipulate the motion ratio.
Is there a formula to figure valving change necessary if I move a shock from a .595 motion ratio to a .8 ratio while the spring stays at the .595? Trying to maintain the same feel, ride and handling characteristics with a different mounting location with minimal testing. Especially when using excessive low speed to control posture (for aero or mechanical grip due to control arm angle). Thanks for sharing your knowledge with us. Very helpful.
Hi Greg. I don't really have any formulas for valving. If I understand the question if you go to a .8 motion ratio you need to have less damping and a softer spring. If the spring is on the shock and you want the same wheel rate as the .595 you need a softer spring.
@The Ohlins Guy right now the spring is at .595 and the shock is at .8. Changing to a class that requires the shock to be mounted inside the spring at .595 which will reduce shock travel etc. I'm thinking it may be under dampened after relocating the shock? 🤔 kinda thinking I may need to reduce bleed and stiffen the valve stack to maintain the same feel and other handling characteristics. I'm going to get out the SAE books and try to speed up the learning curve to avoid expensive trial-and-error testing.
May have found some information in chapter 4 of the Shock absorber handbook by John C. Dixon.
@The Ohlins Guy, so by method of your example using the weight/spring model with the lift, would this be comparable to a lower control arm and a spring/damper. In other words, let's say we are looking at a rear suspension set up of a bmw. Most/ if not all latest 3 series models have a divorced rear set up. Would your example be applicable to it taking less nm/ pounds per inch to move compress the spring than a true coilover setup? Sorry if my question sounds confusing, I am trying to word it correctly. Just from what I gathered I am seeing that a true rear coilover setup would take more force to compress the spring, then a divorced rear setup.
Hi Kali If I understand correctly the spring and shock are seperate. If that is so just survey each one separately. That way you can find out actual spring wheel rate and damping at the wheel. Thanks for the comment....
Motion ratio is quite interesting as it is rarely linear, especially on bikes/motorcycles. So it is great to graph this IE take measurements every cm/ half in. And then on top of that, your track width or on bikes front/rear to center changes causing quite a bit of weight distribution problems.
Your point? Your solution?
@@theohlinsguy4649 Not offering a solution. Just stating that things get complex quickly, more so than many think. IE our mountain bikes may increase the distance the shock travels as the wheel moves up, and this is where a digressive shock tune can come into play. With this the tuner is still attempting to make a linear feeling force as the wheel travels up and back down.
@@theohlinsguy4649 point and solution is if we are going down the suspension kinematics route here, is just make a simple model of the suspension which will generate the relative plot/equation of the shock linkage progression, which needs to be taken into account for how the progression of the forces from wheel movement needs to be compensated by the shock/spring, so the general approach if suspension is linear (fixed motion ratio), then the shock needs to have some progression built into it to resist linearity towards the end of the stroke, while if there is already a solid progression in the lineages of suspension, then the shock could be quite linear with regards to full compression, and the key is to get the HSR to match the spring force at full compression
@@ivanrybkin9384 You lost me at Point! How will you make the springs not linear? What circumstance would you get full compression?
@@ivanrybkin9384 All nice in the technical hypothetical ethers but not very useful where the rubber meets the road. Any full compression event doesn't matter. It is just an anomaly and if you start setting up for that you screw up 99.999 percent of the rest of the track. Springs that we use are linear (I would never use a progressive spring) so what would you do about that?? Perfect is the enemy of good.
For circuit racing, is a geometrical linkage that increases motion ratio (make springing/damping harder as the tires move up, a bad thing? Would there be a benefit to having an initial soft suspension for small bumps then a progressively harder (via linkage not springs), to control roll and make the car more reactive in cornering? Thanks!
Rising rate suspension was all the rage for a while in the 60's. My opinion is that anything that is not linear is not good. Using the damper to control the "platform" is not the best use. That being said I would rather see progressive damping than digressive.
why did it take 3 years for this video to make it to my pc??..
I don't know. I really don't have much of a following as the information I have is not of interest to many people.
Hello good morning, I wanted to know if you can help me set my fork dh38, I can't make it progressive, regards Marcos from Argentina
Hi Marcos Are your forks Ohlins? What is the Ohlins part #? Do you want to add progressive springs? If so, watch my "everything you wanted to know about springs" to see my feeling on progressive springs. I would be happy to help if I can.
Go Doug !!