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I think it's very cool you got your girlfriend's suspension dynoed on Valentine's Day, how romantic,
What does the graph mean?
What does the graph mean?
Its easier to understand if you "unfold it" at the zero-crossing, so it looks like a boomerang. Right of zero (velocity) is the compression of the fork, left of zero is rebound. The dyno puts a displacement into the fork to simulate the wheel reacting to hitting a bump, and measures damping force applied by the damping circuits. The velocity will be high for that upward stroke, to quickly absorb the shock and dissipate it before the bike is upset and your teeth fall out. The velocity will be lower for the rebound of the fork, allowing the bike to recover without overshoot, bounce, your stomach stays inside you, etc. The nice smooth slopes show that the forks were very linear and controlled in their responses, meaning the damping circuits work as designed. A cheap shock/fork will have lumpy, non-linear curves and the wrong slopes. There is a bit of hysteresis at the zero crossing, because there is no real damping for tiny movements (that's the tire's job) and there is always some "stiction".
If it rides and handles well, congratulations. If not, it's Thirdway's fault.
Paul, thanks for the explanation, I've read your response about 5 times now and I almost understand itIts easier to understand if you "unfold it" at the zero-crossing, so it looks like a boomerang. Right of zero (velocity) is the compression of the fork, left of zero is rebound. pg
Still here and struggling to post:Where's Thirdway when we need him
Still here and struggling to post:
Suspension dyno, whatever next had that done by Maxton, it only works on static suspension and ensures there are no major faults. Trouble is, throw the bike on its ear and the perfect traces go out the window. An engine doesn't suffer like that as it is largely in a static environment.
You still have to ride it to see if it works.......against my better scientific judgement mind you
a damper dyno is for testing the dampers only. they cannot test the suspension. one could be made but.... that would be better handled by a 'shaker' rig. as yet, I don't know of a motorcycle capable shaker (meaning one that can reproduce the loads perpendicular to the road surface and and 'normal' cornering loads simultaneously). that would be impressive.Third,
Certainly for street bike suspension, the suspension dynos are simple creatures with limited utility. Like you suggest, they can verify that the damper works properly, there's no valve leaks or blockage, simple stuff. The typical suspension dyno only operates on one damper - fork leg or shock - at a time, off of the bike, so doesn't take into account the myriad complexities of a full bike/suspension system in motion.
For racing, suspension dynos can be very useful, and can actually allow pre-installation setup of tuning parameters. Using accelerometers and other feedback devices, data can be captured from the actual suspension on a particular race track. This data is then fed into the suspension dyno to operate the damper/spring exactly as if it were installed on the vehicle and racing around the track. The damper can then be tuned for best response. Very cool stuff.
I suppose some enterprising (good looking) entrepreneur could develop a dynamic suspension dyno that exercised the bike's suspension in-situ, take it to race tracks and shops, and make a fortune.
Odd. I've never had a problem my end in the 4 or 5 years I've been on here.No, the server seems to be struggling to cope. It's often impossible to log in or post. No problem with other forums just this one.
All on an iPad so it should be straight forward. I can be pressing the post button for quite a while, then I stop and wait half an hour to see if it clears. Sometimes the forum just comes up unavailable. Maybe I'm on the CIA hit list.Odd. I've never had a problem my end in the 4 or 5 years I've been on here.
Can't think what to suggest really, unless it's something to do with your antivirus or firewall permissions or something like that.