enduro250 Posted September 26, 2018 Author Share Posted September 26, 2018 yes, there was an failure in my measurement, will post tomorrow my new results Link to comment Share on other sites More sharing options...
elmo Posted September 27, 2018 Share Posted September 27, 2018 FYI- My swing arm length centers are 535mm, with stock chain and 15T front. Link to comment Share on other sites More sharing options...
Premium Member Evill_Ed Posted September 27, 2018 Premium Member Share Posted September 27, 2018 I just ordered mine from AP Motoarts. 1 "Do not let this bad example influence you, follow only what is good" Link to comment Share on other sites More sharing options...
enduro250 Posted September 27, 2018 Author Share Posted September 27, 2018 yesterday, remeasured, swingarm pivot was wrong, new actual swingarm angel = 10.88 degree I built an object with nail and wood for the simulation. major problem , as we discussed, measurement is not exact enough, in my case a slide gauge and tape measure (correct translation ) the empirical investigation results: stock link 80 mm: for 130 mm wheel movement results in 53 mm shock movement. with very less differences a almost perfect linear run of the curve swingarm angel = 10.88 degree new link 73 mm: for 130 mm wheel movement --> 56 mm shock movement. linear run of the curve as well with the same shock length ride height increases for 25 mm produces an swingarm angel of 13.5 grad for my feelings, that's not exact enough , even if sound serious. I will try to find a solution to calculate this with Math. Link to comment Share on other sites More sharing options...
Mad Posted September 27, 2018 Share Posted September 27, 2018 Stock gearing? Link to comment Share on other sites More sharing options...
enduro250 Posted September 27, 2018 Author Share Posted September 27, 2018 sorry , which gearing ( no English native speaker) Link to comment Share on other sites More sharing options...
enduro250 Posted September 27, 2018 Author Share Posted September 27, 2018 and additional, when I increase shock length for 10 mm ( 310 to 320) ride height increases for 24 mm means for me both changes has the quite same result both have linear curves. reducing link for 7mm results in 3mm more shock movement, I think this negligible Link to comment Share on other sites More sharing options...
enduro250 Posted September 27, 2018 Author Share Posted September 27, 2018 It will be nice if anyone can confirm my calculation / experiment or discuss whit wrong in my thoughts. I'm open for all ideas Link to comment Share on other sites More sharing options...
enduro250 Posted September 27, 2018 Author Share Posted September 27, 2018 stock gearing, yes, if you mean chain sprockets swing arm length in my calculation 530 mm (529.53 mm) swingarm pivot to rear wheel axle leveled length = 520 mm heigth diff = 100 mm 1 Link to comment Share on other sites More sharing options...
Premium Member blackout Posted September 27, 2018 Premium Member Share Posted September 27, 2018 27 minutes ago, enduro250 said: and additional, when I increase shock length for 10 mm ( 310 to 320) ride height increases for 24 mm means for me both changes has the quite same result both have linear curves. reducing link for 7mm results in 3mm more shock movement, I think this negligible The more the shock moves relative to wheel travel, the better. It makes sense that a shorter link, not longer shock, would do this. The better motion ratio gives the shock an easier job at controlling wheel movement with it's valving. Craig Mapstone Upstate New York Link to comment Share on other sites More sharing options...
enduro250 Posted October 1, 2018 Author Share Posted October 1, 2018 I have disassembled my rear end; Looks like I had an additional measurement error: length of stock LINK = 96 mm as result of this , AP Link should be 89 mm has anyone this part available and can provide the length? THX Link to comment Share on other sites More sharing options...
enduro250 Posted November 5, 2018 Author Share Posted November 5, 2018 during the last weeks have done a lot of calculation and simulation of my rear end. sorry, the rear end of my MT (FZ) to decrease the length of this link has the same effect as to increase the length of the shock 7 mm less on the link is almost the same as 10 mm more on the shock . both results in app. 18 mm more ride height and it doesn't influence the suspension behavior. It is a strict linear relationship 1: 2.28 this means for me, I will order a shock with length: 312 mm - 322 mm this gives me a great area for the setup, and didn't need to change the link on the track. 1 Link to comment Share on other sites More sharing options...
wmhjr Posted November 8, 2018 Share Posted November 8, 2018 On 11/5/2018 at 11:24 AM, enduro250 said: during the last weeks have done a lot of calculation and simulation of my rear end. sorry, the rear end of my MT (FZ) to decrease the length of this link has the same effect as to increase the length of the shock 7 mm less on the link is almost the same as 10 mm more on the shock . both results in app. 18 mm more ride height and it doesn't influence the suspension behavior. It is a strict linear relationship 1: 2.28 this means for me, I will order a shock with length: 312 mm - 322 mm this gives me a great area for the setup, and didn't need to change the link on the track. I'm not sure I could agree with this. "Almost" is not the same as "exact". It's not just about ride height. It's also about leverage. I believe the rear suspension with the "ride height link" is still 22% progressive. That being said, I'm probably moving to the full APMoto setup in the rear with KTech DDS Lite. That complete setup reduces the progressive nature to 10%. It is simply not correct to say that the setup is a strict linear relationship or that it doesn't influence the suspension behavior. Link to comment Share on other sites More sharing options...
enduro250 Posted November 8, 2018 Author Share Posted November 8, 2018 sorry, I am not a English native speaker, so I am not sure, to follow you exact. I have done measurement and simulation, a friend in a suspension company as well. we got the same result. if you draw a diagram with wheel movement on one axle and the shock movement on the other axle the result is a straight line , this is what I mean , no progression, here even ,if I use a shorter link , the line is moving parallel does not influence this line itself maybe I use the word progression in the wrong way. As I use "no progression" -> it is a straight line Link to comment Share on other sites More sharing options...
wmhjr Posted November 8, 2018 Share Posted November 8, 2018 3 hours ago, enduro250 said: sorry, I am not a English native speaker, so I am not sure, to follow you exact. I have done measurement and simulation, a friend in a suspension company as well. we got the same result. if you draw a diagram with wheel movement on one axle and the shock movement on the other axle the result is a straight line , this is what I mean , no progression, here even ,if I use a shorter link , the line is moving parallel does not influence this line itself maybe I use the word progression in the wrong way. As I use "no progression" -> it is a straight line I don't think you understand the meaning of "progressive" in terms of suspension. The wheel can only move along the axis of a single arc because it's mounted to a fixed position on the swingarm. However, the leverage curve creates progresssion in terms of suspension performance. The most subtle of changes in terms of lever length or position can have dramatic effects on actual performance and/or progressive responses especially as the system is dynamic, with different feedback as the system moves from maximum to minimum travel. What I'm pretty comfortable in saying is that people making some of these changes and comparisons who are putting bikes on the podium on professional racing and who are experienced engineers and designers probably have a little better understanding than you're trying to duplicate with simple lines. JMHO. You might be able to get "kind of close" - or not. I can tell you for sure that changing link length absolutely changes the relative angles of the swingarm compared to the shock position at least on my bike! Link to comment Share on other sites More sharing options...
twf Posted November 8, 2018 Share Posted November 8, 2018 5 minutes ago, wmhjr said: I don't think you understand the meaning of "progressive" in terms of suspension. The wheel can only move along the axis of a single arc because it's mounted to a fixed position on the swingarm. However, the leverage curve creates progresssion in terms of suspension performance. The most subtle of changes in terms of lever length or position can have dramatic effects on actual performance and/or progressive responses especially as the system is dynamic, with different feedback as the system moves from maximum to minimum travel. What I'm pretty comfortable in saying is that people making some of these changes and comparisons who are putting bikes on the podium on professional racing and who are experienced engineers and designers probably have a little better understanding than you're trying to duplicate with simple lines. JMHO. You might be able to get "kind of close" - or not. I can tell you for sure that changing link length absolutely changes the relative angles of the swingarm compared to the shock position at least on my bike! He is correct. Wheel to shock travel is what makes it linear, progressive or digressive. If for every mm of wheel travel you get same amount of travel at shock than linkage is linear. I have measured it as well. 1 Link to comment Share on other sites More sharing options...
wmhjr Posted November 8, 2018 Share Posted November 8, 2018 3 minutes ago, twf said: He is correct. Wheel to shock travel is what makes it linear, progressive or digressive. If for every mm of wheel travel you get same amount of travel at shock than linkage is linear. I have measured it as well. I'd love to see exactly how you're measuring this, as it flies in the face of what others have said - plus it seems to me to defy physics as if you change the length of the lever that would be impossible. Link to comment Share on other sites More sharing options...
twf Posted November 8, 2018 Share Posted November 8, 2018 I posted pic long time ago. Rod going from rear axle straight up and shock mounted without spring. Than measure movement at rod and shock. I measured stock bike. Found no need to change links. I did modify link to get ride height I wanted. Link to comment Share on other sites More sharing options...
mossrider Posted November 8, 2018 Share Posted November 8, 2018 It's linear. The ratio of axle travel to shock piston travel is the same at the top of the stroke as it it at the bottom of the stroke. I could check my notes but it was basically 2-1 or something (actual numbers are irrelevant) as the ratio never changed. If it was 2-1 at start of travel and 3-1 at end of travel for instance it would not be linear. .02 Link to comment Share on other sites More sharing options...
wmhjr Posted November 8, 2018 Share Posted November 8, 2018 I'm going to have to mock this up. From an engineering perspective I'm finding it difficult to understand how shortening or lengthening the lever would not result in a different ratio. The lever is not perpendicular to travel. Link to comment Share on other sites More sharing options...
Premium Member blackout Posted November 8, 2018 Premium Member Share Posted November 8, 2018 50 minutes ago, twf said: He is correct. Wheel to shock travel is what makes it linear, progressive or digressive. If for every mm of wheel travel you get same amount of travel at shock than linkage is linear. I have measured it as well. 100% Yup! Craig Mapstone Upstate New York Link to comment Share on other sites More sharing options...
mossrider Posted November 8, 2018 Share Posted November 8, 2018 Just now, wmhjr said: I'm going to have to mock this up. From an engineering perspective I'm finding it difficult to understand how shortening or lengthening the lever would not result in a different ratio. The lever is not perpendicular to travel. Have at it, that's what I did. Don't forget there's a lot of fulcrums, bell cranks, levers, angles and dangles that figure in. I am still fascinated to play with it, makes my fat head hurt. And this one is relatively simple w/o any scissor type levers in it. I'm sitting here right now with a small bungee in place of the shock messing with it. Link to comment Share on other sites More sharing options...
Premium Member blackout Posted November 8, 2018 Premium Member Share Posted November 8, 2018 24 minutes ago, mossrider said: It's linear. The ratio of axle travel to shock piston travel is the same at the top of the stroke as it it at the bottom of the stroke. I could check my notes but it was basically 2-1 or something (actual numbers are irrelevant) as the ratio never changed. If it was 2-1 at start of travel and 3-1 at end of travel for instance it would not be linear. .02 Yup, 2-1 would be the motion ratio, but still linear. Our bikes need a heavier rear spring than a S1000RR. lol The BMW has a better motion ratio. Craig Mapstone Upstate New York Link to comment Share on other sites More sharing options...
twf Posted November 8, 2018 Share Posted November 8, 2018 5 minutes ago, mossrider said: Have at it, that's what I did. Don't forget there's a lot of fulcrums, bell cranks, levers, angles and dangles that figure in. I am still fascinated to play with it, makes my fat head hurt. And this one is relatively simple w/o any scissor type levers in it. I'm sitting here right now with a small bungee in place of the shock messing with it. And you can add thousand more or change half of them but on the end all it matters is wheel to shock travel Link to comment Share on other sites More sharing options...
wmhjr Posted November 8, 2018 Share Posted November 8, 2018 Have any of you played with the newer rear suspension links from Andy that allow you to mount the DDS Lite for example? The STX46 still doesn't give me what I'm looking for when pushed past 85% For track days or street it's a great solution, but I think that it's been limiting in racing this year. Link to comment Share on other sites More sharing options...
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