We have been working on a way to visualize damper performance for a while. Over the years of analyzing data, there were still some lingering questions we had about damper performance and quantifying what you are feeling. We pay close attention to the compression and rebound terminal velocities. From the picture below, you can see that every stroke, compression or rebound, has an acceleration phase followed by a deceleration phase. Between these two phases, you achieve max velocity. At the end of the stroke, you are at zero velocity and you are starting another stroke.
We’ve often wondered if a shock was over damped, under damped, perfectly damped, etc. Also, how does your bike behave in high speed chatter like rocks, or long and slow events like a corner or a g-out. What if you are swapping between a coil and air shock, which one is better? Which one supports you and which one doesn’t?
Along this same thread, what constitutes good behavior on a compression or rebound stroke? Could you tell if a stroke was over damped, under damped, etc.? Continuing on with our mission, it’s our job to quantify it, but not make recommendations. By quantifying what’s happening, we can communicate about what’s going on, come up with a hypothesis, and test it out. Bike setup is a science and this science is evolving.
A new dataset to look at stroke performance
Before we dive into the feature, let’s talk about a stroke. Going back to the two phases of a stroke, acceleration and deceleration, how do you quantify the stroke? We wanted to know where in the stroke the max velocity was achieved because we thought this would tell us something about the performance. So let’s look at a few cases.
Compression: Max velocity at the end of the stroke :-(
This would probably be considered bad, but the stroke would need to be looked at in context. Let’s say you hit a rock and you hit the rock so hard that you blew through all of the travel 100%. Not only did you blow through the travel, you bottomed out. You would see this based on the final position of the stroke. But if you also hit terminal velocity at the end of the stroke, what followed next, instantaneous zero velocity. That’s usually never good. You would feel this in your body and hands while hearing a loud clunk in your suspension.
If this wasn’t a bottom out, this would also be bad. This would indicate there is something wrong with your suspension. It was probably under sprung, or didn’t have enough pre-load.
Compression: You achieve max velocity in the first 10% of the stroke
This would most likely indicate that you are over damped. Too much preload, compression damping, etc. We would suspect you are feeling this as an initial harshness.
Compression: You achieve max velocity at the middle of the stroke
We theorize that this would be really good behavior. You hit something, your suspension compresses, achieves max velocity somewhere in the middle of the stroke, then decelerates back to zero velocity.
It is not possible to have a perfect suspension damping/preload, etc. But we think that anything hitting terminal velocity in the middle of the stroke is probably a good setting. There will be outliers based on different actions. A massive G-out may put you at the end of the stroke for terminal velocity. But looking at your overall suspension characteristic, you should be somewhere in the middle.
We are not going to cover every case, but you get the idea of what our hypothesis is. A properly balanced bike will have the front and rear working together in a similar way. A balanced damper should also support the rider in a way that they are not feeling a jarring or harshness. Keep a lookout for trends where terminal velocity of your strokes are not balanced in the middle of the stroke and note how the bike feels as you make changes.
Visualization of terminal velocities to describe damping
In our latest version of MotionIQ, we put together an interactive graph that allows you to zero in on your damping performance for any stroke at any part of your recording. This is pretty cool and has a lot of use cases for racers, suspension tuners, and design engineers.
Stroke Speed Zenith is an interactive graph that allows you to interact with your data with multiple variables. There are 4 slider bars that allow you to zoom into specific ranges of events. If you want to know how your damper works at the beginning of the ride (when the suspension is cool) vs. later, when it’s hot, just adjust the sliders to zoom into the beginning of your run.
The same is true for any of the other sliders. If you want to look at g-outs, you can isolate long strokes and look at a slower speed range, like 0 - 500 mm/s.
If you want to look at small chatter, then just zoom into small stroke lengths.
The possibilities are endless. We haven’t yet found a better way to look at damping characteristics. This will give you a deep dive into how well your bike is performing in various situations. Knowing where your terminal velocity points are within the stroke will give you a really good indication if your bike is properly supporting you.
The Stroke Speed Zenith chart is available in the MotionIQ Pro app. It is located at the bottom of the Front and Rear summary pages.