How RockShox Tests and Develops Suspension, and Why Service Intervals Matter

Chris Mandell is the North American Public Relations Manager for SRAM where he’s worked for the past 8 years. He currently lives and rides in Bellingham, Washington. 

• Is mountain biking suspension harder to design than say suspension for cars or motorcycles? What’s different?
• How much of RockShox testing is real world vs. lab based?
• Is shock heat management important for the average rider?
• What is the advantage of larger diameter fork stanchions?
• What’s the idea behind the electronic suspension controls in SRAM Flight Attendant?
• Why aren’t there more inverted fork designs?
• What are some common misunderstandings about mountain bike suspension?
• Are suspension designers as focused on reducing weight as they have been in the past? By loosening weight requirements, what improvements can be made?
• What’s your method for setting up a new fork?
• Which suspension innovations are you most stoked about?

A full, edited transcript is provided below.

Jeff
Hey everybody, welcome to the Singletracks podcast. My name is Jeff and today my guest is Chris Mandell. Chris is was the rear shock Product Manager at SRAM Rockshox where he’s worked for the past eight years. He currently lives and rides in Bellingham, Washington. Thanks for joining us, Chris.

Chris
Yeah, no problem. I’m actually the former rear shock product manager. I am currently the North American public relations person, but I was the rear shock Product Manager for four and a half years. Lindsey Watson replaced me as the rear shock product manager just a little bit ago, and I’m really stoked to have a replacement.

Jeff
Well, thanks for the clarification, I guess I should tell you, maybe you need to update your LinkedIn profile.

Chris
I do need to update my LinkedIn profile, it’s not a thing that I look at, very often. That role was huge for me. And I had a really good time working on that team. You know, it’s a pretty fast-paced environment, working in the Rockshox product development space, especially on the rear shock side of things.

You know, in terms of development you’re working on a lot of projects that are specifically for Rockshox but then we also do quite a few specific projects for our OEM partners where we’re working on products that are specifically for their bikes. So a really good example of this would actually be the wicked rear shock that the rear shock team just completed for Specialized on their new epic World Cup.

Jeff
Yeah for sure. And in this podcast we’re gonna be talking about mountain bike suspension. And so that experience obviously is a big part of your expertise, and why we’re stoked to have you here.

So tell us a little more about your background, like how did you get started sort of working in bikes and suspension and all that stuff?

Chris
So I followed a pretty similar trajectory, probably to a lot of people who are in the bike industry, In college I was working at a bike shop, and had originally gone to college to play American football. I found really quickly that I didn’t like that, or I didn’t like it at the collegiate level, I should say. I found mountain biking and started riding singletrack and really, really enjoyed it. And then right after college, I went from working in a bike shop to working at Full Speed Ahead and then worked out for a few years as an inventory manager, and then became a product manager at Kona Bikes, and did that for about six years, which was really formative, and a great learning experience for me.

Then in 2015 I joined Rockshox as the rear shock product manager, and did that from from about 2015 to sometime in 2019, and that role was based in Colorado Springs, Colorado. So my wife and I moved from Bellingham to to Colorado for that job. And then for some family reasons, I had to move back to Bellingham. Keep in mind, this is before the pandemic, so they weren’t working remotely, that was kind of not a thing. But SRAM was really amazing and they were very understanding as to the reasons I needed to move back. And I wasn’t able to continue being their shock product manager because that’s a job where you really need to be hands on. But they did keep me employed.

Eventually, I found my way to taking care of communications for North America and Oceania. And so it’s been a big transition for me being someone who worked in product for all of my career, and then moving over to the communication side of things. But it’s been really good and also provides, I think, you and your listeners with the opportunity to get someone who has like, worked in product development on the suspension side of things, and on complete bikes, the ability to kind of like speak to it in these contexts.

Jeff
Right, right. It’s really interesting, the interaction between the shocks and the bikes, like the frames, because […] it’s really important to consider that when you’re looking at the shock and how it interacts.

Chris
Totally. There’s the interplay between the kinematics of the frame, the stiffness of the frame, all that interfaces with how the shock is designed and what you’ve designed the shock to do. And then there’s also the component of our OEM partners are looking for their bikes to ride in a specific manner. And so a lot of the tuning work that we do with them is to achieve whatever that customer’s goals are in terms of the performance of their product. So you can have two companies that have relatively similar leverage rate curves. And they’ll make totally different tune decisions simply based on how they’re looking to have that bike ride.

Jeff
Yeah. Before we jump into kind of talking about that, you mentioned that Rockshox is in Colorado Springs, but it’s a part of SRAM, which is, you know a mega big corporation, I believe, mostly based around Chicago area, right? But they’ve kept Rockshox in Colorado Springs, obviously that’s somewhere where you can do a lot of testing and that sort of thing. Is that the idea behind sort of keeping Rockshox separate and giving it its own space?

Chris
So when SRAM acquired Rockshox, they were based in Colorado Springs. And that’s where the development and actually at the time the manufacturing was. We actually do quite a bit in Colorado Springs. So hydraulic, all of our hydraulic disc brake systems are actually also developed in Colorado Springs, as well as just a bunch of other things happen there. You know, I think SRAM really is a global company, so we do have a lot. Chicago is where our headquarters are. And we do a lot of industrial design and product development there. But we also have facilities in San Luis Obispo, Spearfish, Indianapolis, and then obviously, the Colorado Springs office. And then you know, we do quite a bit of development in Germany. And then we have a production facility for chains and Zipp wheels as well in Portugal. And then we own our own factories in Taiwan and do quite a bit of work there. And there’s actually a couple of locations that I’m leaving out.

My point there being that we have a very global presence and it it gives us a really broad perspective of what the cycling community needs and allows us to be members of a lot of different communities across the world, which allows us to see trends as they come up a lot more quicker than we would if we were centralized and in one location. Another place where we have a presence — I obviously work from home in Bellingham Washington — but just across the border in Vancouver, we have an office with I want to say 14 individuals there, but don’t quote me on that. So you know, we really are a global company with an eye toward how cycling exists across the world.

Jeff
Yeah, right. So many different styles of riding and terrain and everything in it sounds like, I had no idea that SRAM was like that kind of decentralized in terms of the development and the different things and sounds like you’re able to take advantage of the experts in those places, and really get a good sense of the way that people use their bikes.

So let’s talk about mountain bike suspension. To me, it’s still relatively new. We’ve been having suspension on mountain bikes since the late 80s, early 90s. But obviously, suspension has been around for things like cars and motorcycles for much longer. So what’s different about designing suspension for bicycles versus those other larger vehicles?

Chris
Yeah, so it’s interesting to know that Rockshox has actually been there from the from the beginning of suspension on bicycles. It is quite a different thing.

While I haven’t directly been involved with designing suspension for motorcycles or automotive applications, bicycle is a different thing. On a car, you’ve got a motor and the bulk of the weight of the system — so, the vehicle plus the occupants — is in the vehicle, not the occupant or the individual. And that center of gravity doesn’t really like move around or the center of mass rather doesn’t really move around, right?

While weight on some motorcycles is a consideration, it’s not the massive consideration is on a bicycle. So that’s, that’s another characteristic. And then, and this is this may sound a little bit trivial, but we’re trying to have an experience to connect with the outdoors while we’re riding our bikes. Noise is another really big thing.

I don’t know if you’ve ever heard a motorbike just coasting down the hill with the motor turned off but you know, there’s a ton of chain drag, there’s a ton of plastic slaps, and then you think about the motor being turned on and like you really can’t hear any of the noise that your suspension is making. Like you really notice if your suspension is making like Slurpee, crazy noises because it’s quite distracting. So as trivial as it sounds we do actually spend quite a bit of time making sure that products are quiet so that you can have like a connected experience on your bike that’s connecting you with the trail.

But you know, in bicycle suspension or any suspension, actually, in this particular situation, you know, you’re moving some amount of oil from relatively high pressure zones to relatively low pressure zones. And when you do that, you have a lot of like eddies and vortexes that are created. And that’s what creates that kind of like slurping noises. And so you have to be really careful with the way you design those transitions from the high pressure areas to the low pressure areas, so that the oil flows smoothly in between the two of them, and doesn’t create noise. And that’s something that we do on shocks and something that people will notice, especially in the MY23 Charger 3 damper that we came out with is very noticeably quite a bit quieter.

Jeff
Interesting.

Chris
It’s something we pay attention to. So there’s a lot in there. But like the noise one is a really easy one to for everyone to kind of like quickly imagine as this is a pretty big difference.

Jeff
Yeah, and anytime there’s noise. I mean, that’s like energy. That’s an energy loss. And I feel like, you know, most bikes — I mean we have electrics now, but for the most part bikes are human-powered. And we want to conserve every ounce of energy that we can put it back into propelling the bike. And then obviously that adds complication as well, because you’ve got those pedal forces, like you said, our bodies are moving around and center of gravity is constantly shifting. So it seems like a super big challenge.

Chris
Yeah, with what you just pointed out there there’s two layers to highlight: pedaling efficiency and then rider body position changing on the bike. And in both of those instances, we’re developing suspension to maintain stability and not reacting to pedal inputs. And making sure that, as a rider moves around their suspension responds in a consistent manner, doing all that while also being very responsive to inputs at the wheel. And so you have to think really carefully about what shafts speeds and how you’re going to build a system to sort of deal with those two sets of inputs.

Jeff
Yeah and so continuing that vein of, you know, thinking about energy, how it’s lost and returned in a shock. Another thing that — maybe it’s a minor thing — but is heat management important for the average rider in a shock? Do shock temperatures matter? And how do you deal with that?

Chris
Yeah, so shock temperatures do matter, you do heat up your system, a number of different ways. So oil moving through the shock does generate — there’s friction with oil moving inside of a shock, you also have the adiabatic process in an air shock system, which is when you have a very fast shaft speed. There’s a point at which the shaft speeds become so quick that there isn’t enough time for pressure to increase in the air can just from the physics side of things, the pressure can’t shoot up that quickly. And so that energy goes into creating heat instead of going into creating an increase in pressure. And then that is dissipated.

So it’s definitely something that we pay attention to see, you know, some of the differences in feel between a coil spring and an air spring would be a result of that adiabatic process. But it is something that we’re aware of, we know what the max temperatures for a given ride experience are going to be. And we develop our systems — primarily the rebound system because that would be would be the first impacted by it — to manage that as best as we possibly can.

There are some kind of surprising pieces in there, like, you’re gonna see a higher absolute temperature on a coil shock than you would see on an air shock. And that’s simply because the coil shock has less surface area with which to dissipate. Surface area is what’s going to allow you to sort of bleed that off into the environment as quickly as possible. Another little tidbit is that it’s not necessarily the highest speed trails that ended up generating the most heat in the shock. It actually tends to be slower speed trails that have really big compressions that result in generating more heat, simply because you have less airflow over the shock. So more and more temperature is able to build up.

So yeah, it is something that we consider and it’s something we pay attention to as we’re developing products. It shouldn’t be something that really impacts the end rider as in their riding experience. But it’s definitely one of the things we pay attention to.

Jeff
Yeah, that’s kind of what I was wondering is, if the average rider is actually pushing the shocks to that level? Or if this is something that, you know, really, we’re just talking about, like, pro racers who are going to notice maybe a little bit different performance, like at the start of the run versus the end of the run?

Chris
I think it’s it has less to do with, in terms of like how much heat is going to be seen at pro racer versus like, really astute amateur, it probably has more to do with like, the trails and the trail situation that’s being ridden on. But again, we’re very aware of like, what the boundary cases would be, or like what the worst case scenarios are, and we design our systems as best we possibly can to sort of manage that. And we do that through various different ways. Like, the surface area of the shock, the amount of oil in the shock, what type of oil we use in the shock. There’s just a bunch of different factors that kind of go into that.

Jeff
Yeah so that kind of leads me to my next question about testing and development. How much of testing for suspension components is real world versus lab based? I imagine it’s a mix of the two. But which one is like, are you spending more time on and learning more from?

Chris
I’m really glad you’re asking this question they go hand in hand is really the answer to that.

You know, we’ll have an engineer develop a thesis for something. For example, they’ll say, high frequency vibrations are what leads to hand fatigue in riders. And then they’ll say, Okay, can we develop suspension technology that reduces the amount of high frequency vibrations that reach the rider. And then they’ll they’ll develop the technology.

In this specific case, I’m referencing buttercups in the fork, and they will do blind, back-to-back testing with a rider. And that feedback will get written down, then they will also do some type of lab test that checks off and puts high frequency vibrations into a system, and then has a way to test the end result of that.

And the only time we go forward with a technology is when we have the theory — so like, the hypothesis that the engineer had come up with, the lab tests, and the rider test, the blind rider test feedback — all pointing in the same direction. So if one of those was to not line up, that would send us back to the drawing board to keep iterating and keep thinking about what we’re doing.

Just to kind of give you like an even more sophisticated example of how this kind of plays out sometimes: When we were developing the model year 23 Rockshox forks — so the new Zeb, Lyric, Pike with the Charger 3 damper and the buttercups — the lead engineer on that, and his sort of main test engineer, are the same size. And they actually forced themselves to ride the exact same setup on the same bike. And what they ended up doing was they built two identical bikes on the same day. Everything’s the same — same pedals, fork, handlebars, grips, all of it, and they would go out and ride together. And one bike would have one thing that was different from the other bike.

What that allowed them to do was instantaneously switch bikes in the middle of a ride without having to do anything, they could just jump from one bike to the other. And it was the exact same ride experience except for they changed one thing on it. And that allowed them to get really direct, really quick on-trail, back to back comparisons, that they could then flip around and test in a lab to see if the feedback that they were giving lined up with what the test data feedback was also giving and. That really is what allowed us to like get to a lot of the refinements that we had in the MY 23 product line.

So if we just stick with the Butter Cups example for a second. If you take the buttercups apart the rebound and compression, rubber bumper components of the Butter Cup is actually different rebounding and compression on the air spring side and on the damper side. And that really came from like a lot of back to back testing and like putting Butter Cups only on the air spring, putting butter cups only on the damper. Having the rubber elements be all the same on each side. And then realizing that we needed to change them from side to side, changing the durometer of them, riding them at hot temperatures, riding them in cold temperatures, and really kind of like parsing out what those systems needed to be for their specific application.

Jeff
Yeah, that’s interesting. It’s almost like, you know, not to minimize the engineering and the science behind it all. But some of it sounds kind of like guess and check, like where you’re just like, okay, we think maybe this is going to make a difference. But we don’t know, you know, do we put it on the rebound side? Or the compression side? Like, let’s go out there and try it out. Are there a lot of things that you try, and nobody can tell the difference? Like you do the blind test, and it’s kind of inconclusive?

Chris
Yeah, that absolutely happens in it. To touch on the guess and check thing for a second, innovation, and developing new things is, is like a tricky, difficult space. You know you have to have your eyes and your ears open to what’s not working today. And you have to see those things. A lot of times, at least for me, they come across as feelings. And it’s different for different product developers. But you know, you basically, you come to understand a problem that can be solved. And then you really do have to, like, display some courage and go out on a limb and propose some things that might sound crazy initially to solve those problems. You know, I think guess and check might sound like a little bit trivialized or like maybe not serious, right?

Jeff
Yeah. You’re not just getting lucky.

Chris
But yeah, it really is, like, you know, to properly guess and check, you have to make sure that you’re not getting confused information, you know, you got to like make sure that your test is actually telling you what you think it’s telling you. So yeah, I think that’s a good way to think about it.

Jeff
Yeah, right. It’s definitely iterative. And you’re not just guessing just like pulling things out of the air. There’s the theory at first, and then there’s a… you try something and it doesn’t work exactly the way you thought it would work. But you kind of refine it along the way. And yeah, it’s a fascinating process.

Chris
Yeah. And I mean, you can imagine that process, you come up with a theory, you try to test it in multiple different ways. Sometimes you have to look back at your test and make sure your test is actually telling you what you think it is. Because you could not be seeing what you think you’re seeing in the test. You know that’s why it’s important to have experts. You know a dyno, for example, which we’ve put a suspension product on it, it applies force to it, and then creates a graph. Well, if that dyno is not properly set up, if the tech operating the dyno doesn’t know exactly how to read the graph, there’s just a ton of factors that go into that. And that’s a place where you can get led astray. And I’ve seen people get led astray, really quickly, by this really fancy machine. Again, if you don’t know how to use it properly, it just doesn’t help you.

Jeff
Right, yeah. And it’s also really interesting to see kind of behind the scenes and to understand, like, all the testing that goes into this, and, you know, checking and double checking things and making sure that the solution is completely dialed before you come out with a new product. I think, you know, on the one hand, we’re like, oh, you know, there’s always new stuff. And mountain bike innovation is just so fast. And it’s always something new.

But on the other hand, we’re like, oh, man, it’s been like three years since they updated, you know, XYZ product. And it’s like, well, there’s obviously a lot that goes into that stuff. And these things, these things can take time, depending on on what you’re doing.

Chris
It takes takes a ton of time and energy to innovate and to take those innovations and get them to a production level thing. You know, one thing is — and as we’re kind of going back and forth about this — I’m like thinking about how this ends up landing down to the rider and the ride experience that you have on the trail. One of the things that pops up to me at that point, in my mind there is the first step that a lot of those engineers are doing when they’re getting onto a product is they’re making sure that their setup is correct.

So like the making sure their air spring setup is correct, then they’re making sure that their rebound setting is correct for the spring that they have. And then they’re making sure that compression choices that they’ve made on the fork are going to tell them what they need to know, for the ride experience or are appropriate for the trails that they’re going to ride. So I think I think one thing for all these listeners to keep in mind too, is like, the really basic things like setting sag, setting rebound, and being attentive to those details is a shared experience between a rider on a trail in Arizona, or Spain. That is also the same experience that one of our development engineers would be having in Colorado Springs.

Jeff
Yeah, right. That’s a really great parallel, this experience of like designing and testing is something that we as riders need to do as well, whether we like it or not, that’s the only way to set up your suspension properly. So why don’t we talk about that: What’s your method for setting up a new fork or a new shock? What’s the process like?

Chris
Yeah, so it’s a little bit different for forks and shocks, but not too terribly different. And I do think we spend a lot of money on these bikes, the suspension is a big percentage of that spend. And as much as it would be great if there was a silver bullet to do it, it isn’t like that. It does really help your user experience if you take the time to do proper setup.

So we have invested a lot of time and energy into our app, which provides a really good initial setup for the fork and the rear shock, air spring, and the rebound setting. And the way that I like to think about this is like you’re looking to get inside your window of happiness. So there’s like settings where you will be unhappy, which would result in you being outside your window of happiness. And then there are the settings that are getting you into your window of happiness. And those starting suggestions really are aimed at getting you close to your window of happiness, getting you to inside the window of happiness, so that you can then kind of refine from there.

Jeff
Yeah, this is a good way to put it, because a lot of us, you know, we get a new fork. And I don’t know, I haven’t set up a new fork in a while but you know, used to be there’s like a chart and you find your weight on there. And, you know, there’s like a recommended pressure that you start with. And I think for a lot of people, they’re just like, Yep, that’s it I’m done. But it sounds like that’s just kind of the starting point.

Chris
Yeah that recommended pressure should get you into your window of happiness, it should be a really a great place to start taking it to the next level. It really requires going out and like riding your bike, ideally in a relatively systematic kind of a way.

What I like to do, and what I suggest that people do, and what we do when we’re doing suspension testing, is we will take someone to a piece of trail that’s representative of the kind of riding that they’re going to do or the bike is intended to be ridden on. Like you want this to be 30 seconds of trail, two minutes is great, five minutes is probably kind of too long. And ideally, you can lap it and do quite a few repeats on it.

And so start off with those recommended pressure settings, and use the guide, the recommendation from the SRAM Trailhead app, you can also use that for the rear shock. On the rear shock, you could also set sag, which is another really great way to do it, aim for 30% and then do a lap down that section of trail. And you don’t need to write it down or unless that helps you. But just kind of like your impressions of what that was like like, what did you feel in your hands? When do you feel your feet? Did you feel like you were way forward on the bike? Do you feel like you were way back on the bike. Just kind of like think about some questions about what you were feeling about what you were experiencing. And then go back up and do another run, which may seem redundant, but you kind of want to get warmed up. And you kind of want to see if you had the same experience on the previous run as you had on the on the last run.

And then it gets a bit open at that point. Because what you’re really trying to do is you’re trying to say like, what am I experiencing that I don’t like or could be improved upon? So let’s say for example, you do that run and you’re like, Wow, I feel a lot of weight in my hands and I don’t actually feel like much of my weight is on my feet and kind of feel like my nose is over my handlebar. That might suggest that your rebound is too slow on your fork or that you don’t have enough air pressure in your fork and you’re ending up really far out front over over the front of the bike. So if someone came to the bottom and gave me that feedback, I might try making a minor adjustment to their fork and then having them do another lap, and seeing what they think.

A different example of what the feedback could be is they come to the bottom and they’re like, I clacked bottom out twice. And it’s okay to bottom out, like you do want to use full travel. But if clacking bottom out twice, in a relatively short run on a piece of terrain that doesn’t feel appropriate for that would tell you like, oh, we should bump up your air pressure, or think about increasing the ramp in your air spring.

So this is where it does get a little bit open ended. And you really have to listen to yourself as a rider and, and recognize that like, you are the expert in that space, like it’s you who is going to be riding the bike down the trail, it’s you who needs to be comfortable. And you should feel comfortable making changes to the suspension on your bike to try to improve your experience.

Jeff
Well so what does someone do, is there like a decision tree kind of? You mentioned a couple of examples of like, if you’re feeling this, do that. Is that part of the Trailhead app? Or is there a way to like dial in your suspension without necessarily knowing all those things? And maybe like starting in the middle, or starting at one end and working your way the other direction?

Chris
Yeah, so the starting point, there is that Trailhead app and the recommendations that would give you in terms of like rebound, or air spring rebound. And then going from there. I mean, the decision, the decision tree really is like what you’re feeling and experiencing on the trail, and like how you want to change your ride experience based on on what you’re feeling.

We do have technologies that can help in that space. For example, ShockWiz is a really good aftermarket component that you can bolt on your fork or your shock, and it will offer suspension setup recommendations. So that’s a really great tool, if you feel like you don’t have that knowledge. But I also think it’s not a static thing, like you can do this one time, feel that experience, go on, make some changes, or stick with the settings that you have, and then carry on riding your bike. Do it again a couple of months later, and see if there’s a change in your experience.

Personally I change my set suspension settings over the course of the summer, you know, the beginning of the summer, I’ve been skiing a little bit more than biking. And by the end of the summer, I’ve just been biking. And so my fitness is transferred completely over to biking. And so I end up running like a little bit different suspension setups.

Another pretty big factor is the terrain that I ride on changes pretty radically from winter to summer. It’s softer in the winter, there are wet roots, the trails run relatively slow, and then summertime, the ground gets really hard packed, the roots are very dry, the speeds increase quite a bit. So I think that’s one of the other things that everyone should keep in mind is like it’s not a static thing, necessarily, you can’t make it a static thing. If it is best for you to maintain very consistent suspension settings, then you should do that, that might be the best thing for you. Because it gives you the most consistency.

However, you can also adjust your setup based on time and progression, by taking the time to think about your setup, leverage the starting point that gets you into the window of happiness in the Trailhead app. And then going out and systematically riding on a short section of trail making a change, riding it again, making a short, quick change. This is the kind of thing that can be really helpful in getting you to the next level of performance.

Jeff
Yeah it sounds like going through that process is super helpful. But it also sounds like it really pays to understand how the suspension works and and if you’re feeling this, then that means that you need to do that to your your fork or your shock. Because like you said, our fitness changes or riding style changes throughout the year or, you know, as we progress. Trails change. I mean, there’s so many things that change that. It doesn’t really make sense to just say like, Oh, well I always run three clicks on rebound and, you know, minus two on compression and like, that’s it. It doesn’t sound like that’s that’s necessarily going to give you the full advantage.

Chris
Yeah, you know, I think it’s a bit of a learned thing too. Let’s say tomorrow you decide you’re going to try this out, and you go out and do. You could do a run with your fork at the current air pressure with your fork with a few PSI more. And then you could do a run with your fork a few psi less. And that set of runs will give you a bracket for how your form changes with more or less air. And then your mind and your body at that point would understand how that change impacts you as a rider.

Jeff
That’s that’s a good point. I hadn’t thought of the process in that way before. Like, I think for me, the process was always about like finding the number. But it sounds like it’s really about learning and understanding the relationship between the number and what you’re feeling.

Chris
Yeah. And, you know, I think we we spend so much time making sure that our suspension recommendations in the Trailhead app are going to get people to, like inside the bubble, the window of happiness, like in that space. And then for a lot of people that’s like, great, and they can ride in those settings for their entire ride experience. But for other people, it’s important to sort of like refine and take it to the next level. And for those people that were doing something like this, and being systematic about it, it is helpful. And, you know, if you think about the people who have spent a lot of time working on suspension and diving into suspension, you know, they weren’t born with an innate ability to parse out the difference between a digressive rebound tune and a progressive rebound.

Jeff
I’m glad you said that. Because I’m always confused when I start talking to those people. And I’m jealous. I’m like, how do they… I can’t wrap my head around this. But yeah, yeah, probably just because I haven’t experienced it enough.

Chris
Yeah. So with with those people, the thing that those people have done is they’ve spent a lot of time doing a run, making a small change, doing another run. Now, they might be changing between two shocks that have two different shim stacks. And that’s one thing, but their version of that is, if you’re currently riding it, you have a shock that has 15 clicks of rebound. And you’re currently riding at nine from closed, try riding a lap on seven from closed and try doing a lap on 11 or 12 from closed. And if you do that, you will feel the difference between those three settings. And then you’ll know what rebound is doing for you in different circumstances. So like, you will feel a difference in that rebound, both on like small bumps. But you will also feel that change in bigger compressions that are using more of your travel.

Jeff
Yeah, that’s super helpful. And yeah, it definitely motivates me to get out and do more of that type of testing, hopefully, for listeners as well, because it sounds like there really isn’t a substitute for that. And if we want to understand this, and we want to dial in our bikes more, this is just the way to go.

Chris
Yeah, I mean, I, you know, I think that starting point of what you get from the Trailhead app in terms of setup, initial setup is really great.

Jeff
Yeah, well, let’s get back to talking about some of the technology behind suspension systems. So we talked about heat management. And you mentioned the ShockWiz as like sort of a way to monitor your shock and understand performance more. Tell us a little bit about electronic suspension controls. What does that do for people and for SRAM? So what’s the idea behind SRAM Flight Attendant?

Chris
Yeah, so this this is is different from Shock Wiz. Shock Wiz is aimed at giving you feedback on your suspension setups. Flight Attendant is aimed at increasing the efficiency and your overall ride experience on your bike.

So for years now, the holy grail of suspension has been giving you a ton of efficiency while also being able to absorb bumps at any moment. We kind of spoke earlier about how bicycle suspension design is quite a bit different from like automotive suspension design because of that.

The added feature that we get with Flight Attendant is because we’re able to integrate the full system and get much closer to the riders intention with an electronic system. It allows us to provide the rider with a much more efficient ride experience. So more of your energy, more of your pedaling power is going into forward momentum in a way that is just not possible with other systems. So yes, we do provide cable lockouts and that sort of thing. But that requires a lot of mental application by the rider. Whereas Flight Attendant, you don’t have to do anything, you just get onto your bike and the bike does the work for you.

Jeff
Yeah, I mean it seems almost too hard to believe. Because, like, how does it know? How does it sense what the terrain is? The way I’ve heard it described is kind of that it’s like able to react quicker than the rider can. How does it distinguish different inputs from each other? Like, how does it know that you’re just starting to hit a big rock versus like, you’re just hitting a small rock, and you’re already almost over it?

Chris
We put a lot of work into the accelerometers and how the information that’s coming from the vibrations, and the four different vibrations at the fork and the shock are seeing the those big impacts or small impacts, and how the accelerometers in the fork and the shock, sort of manage that input and then change your state based on that.

And then the other piece of information that we use to infer rider intent is the pedal sensor, which is based in the cranks. And so what we found, as we were developing Flight Attendant, and we had sensors all over the bike, and we’re looking at a ton of different pieces of information to try to parse out rider intent, what we realized is pedaling input gives you a lot of information about what a rider is intending to do on the trail. It doesn’t tell you the whole story but it tells you a lot of of it.

So by putting the pedal sensor into the system, along with pitch detection — so like if you’re going up, or if you’re going down — is also a piece of information that we use to predict the future. So the Flight Attendant algorithm knows what has happened in the last few moments and uses that along with the pitch information. And then the rider input in terms of whether the rider is pedaling or not pedaling to think about what future sections of trail could look like and make a decision based on that, telling it which state it should be in.

Jeff
Interesting.

Chris
So the point of all that, I would say is the element of the vibration, or the impact sensor, in the fork module and the rear shock module. And then the ability for our system to flip to open is a component of Flight Attendant. But it’s wrapped up in this bigger package that the algorithm combines together to paint a more accurate picture of what’s happening in the future and what the rider is looking for at that moment. Is the rider looking to have an open, bump gobbling suspension state? Or are they looking for a little bit of pedaling efficiency? Or are they just pedaling up a road, and we can go to full lockout? And those are the kind of layers that that I think, really make Flight Attendant, a kind of a magical riding experience where you as the rider, just get on your bike and ride without having to use your brain to get to a more efficient compression state, you can just ride your bike and the bike is going to create the most efficient state for a given moment.

Jeff
Yeah, that makes sense. I’m sure that our bodies kind of tell us what’s about to happen. Like you’re saying, you know, if we see a big rock coming up, like our pedal stance is going to be a little different than if, you know, it’s just a minor bump. And so yeah, I guess having all of those inputs, you really can make some good predictions about like, where the suspension should be set, and all of those things, so very cool.

So what about inverted fork designs? Why don’t we see more of those? Every suspension person I talk to is like, oh, it’s the best design. It’s amazing. It’s clean and you know, super efficient. Why aren’t all forks inverted?

Chris
Yeah, so I mean, we’ve we’ve done inverted works before. The RS1 I think was like the most shiny example of like a really elegant, effective inverted design. However, the technology today really lends itself to the current setup of forks with having magnesium lower legs and aluminum upper tubes, just in terms of efficiency of design when it comes to the stiffness-to-weight ratio, ease of maintenance and working on it, ensuring the entire system is well aligned. The ease of getting wheels on and off, cable management. There are advantages to inverted designs, but there are a lot of costs that come along with that. And when we look at the problems that we’re trying to solve a traditional fork design is the most efficient way to do that.

Jeff
And you mentioned, I think you mentioned stiffness is being like one of the challenges with that. What about stanchion diameters, is that also being driven by stiffness, or are there also like suspension properties in terms of the volume of air that you have in a fork that makes a bigger stanchion better for longer travel bikes?

Chris
Yeah. So the there’s, there’s kind of a lot there. I would say first and foremost, when we are looking at stanchion diameters the trade-off between weight and stiffness performance is based on the length of the forks. So the longer your fork gets, the more travel you’re adding, or the the bigger the wheel size, the easier it becomes to solve and get to the correct stiffness with a bigger upper tube. So that’s really kind of the dynamic that’s at play there.

And then in terms of how that fits in with the air spring side of things, we have a ton of levers that we can pull off on the air spring side of things. And so between negative air spring volume and positive air spring volume, and all those different things, that allows us to sort of build the different air springs we need based on on the upper tube size.

Jeff
Okay yeah, that makes sense.

So, let’s talk about some misunderstandings or misconceptions about mountain bike suspension. What are some things that maybe you’d like to clear up? That maybe people might not understand about mountain bike suspension?

Chris
I don’t know if this exactly answers your question. But the first thing that comes to mind to me is, in the motorcycle space, there’s a really strong ethic of getting your product serviced at the exact service intervals. And I think I think cyclists struggle with that a little bit. And I would say, the misconception is that you can just run your bicycle suspension fork or your dropper seatpost, forever, and it’ll be fine.

And what I would say is you should be attentive to your service intervals. And one thing you’ll notice is… I mean, first of all, you can Google SRAM service intervals. And you’ll see we have, on one consolidated page, our service intervals for brakes and suspension all together. We spend quite a bit of energy and time trying to make sure that we blocked that stuff off so that you’re not like, bringing your fork in to get serviced and then two weeks later, you’ve like, put another 10 hours on your rear shock. You can do those two things at the same time. And it really does have a big impact both on like, how much value that product is going to provide to you over time, because it’s going to last longer. But it also is going to give you a better riding experience over time.

Jeff
But do people need to be like, you know, if it says 100 hours, like right at 100, you need to get it serviced, or is it kind of depending on how you ride and your conditions and that sort of thing?

Chris
Yeah, there’s there’s a bit of like how you ride and conditions. For example, like with our DOT brakes we recommend that you bleed your brakes or replace the fluid once a year. Now, if you’re riding in a very aggressive place, like Morzine in France would be a very good example of quite a steep place. You know, Whistler would be another example, that might be a place where you want to do it a little bit more often than that.

And then on the suspension side of things, like the hours would be like lower leg and air can service on your fork, plus or minus some number of hours on that front. You don’t need to do it exactly at 50 hours, but like if you’re in the ballpark of 50, it’s going to make your product last longer, and it’s gonna give you a better ride experience.

Jeff
Yeah. That’s a tough one for a lot of people, I think because, I mean, we ride a lot, right? Like, we just did a survey asking Singletracks readers like how often they ride and you know, for most people, it’s at least two or three times a week. So even if you ride like an hour a week, you’re at 50 hours in a year, right? And people are doing like 10 times that so I mean, are we are we really going to be servicing our forks, like, every couple of months?

Chris
I mean, to keep that product working in tip top shape that would that is our recommendation, you know. That that is going to result in like the product lasting for as long as that rider wants to, and is also going to give them the best feel in terms of performance. These are pretty high end products. Like we’re not talking about like Formula One stuff that has to get rebuilt every single race.

But for example, I was just looking at automotive brakes. You’re supposed to have maintenance to your automotive brakes every six months for 20,000 to 60,000 miles. Which is a lot. And I’m like, surprised by how often that is. But again, it’s kind of the same thing, like these are sophisticated products that are designed to provide high performance and that requires some level of maintenance.

Jeff
Yeah. I’m just doing the math in my head. And if I do like three rides a week, and each one’s an hour to two hours, I mean, it’s every 10 weeks, that I need to be, you know, checking that stuff, which I’m sure most people don’t do that. And so it would be interesting to see kind of what benefit you get from that. Because the other thing is, we don’t notice that degradation in performance over time, either. And so, you know, it’s easy to think like, Oh, it’s fine, it still feels good, but you don’t realize that it doesn’t feel nearly as good as it did when you first got it, or, you know, since the last time you serviced it.

Chris
Yeah, I think that is a that is a super good reason to keep thinking about this is like, things do degrade over time, you replace it, all of a sudden, you have new fresh clean oil and grease in the places that it should be. And it’s just like a better experience.

And I also think it’s a good way of maintaining the value in the investment that you’ve made. We’ve all invested a lot in these products. And we want the value to be maintained over time, you know, fully switching gears from suspension, one of the one of the internal use cases that we discussed with Transmission, and making the skid plates on the derailleur replaceable is like, yeah, if your derailleur gets scuffed up, and you want it to look nice, for your own personal enjoyment of it looking nice, or you want it to look nice if you’re going to sell your bike now, and you want your derailleur to look fresh on your bike, those are two very valid use cases for making that outer skid plate replaceable on that derailleur.

And I think suspension is the same situation. I recently purchased a bike for my daughter on Pinkbike buy and sell. And one of the features of the ad that the individual who was selling it posted was that the suspension on the bike had been recently serviced. […] I was drawn to that advertisement […] because I knew that that individual clearly took care of the bike. So I think there’s a value to you as a rider to have that. But there’s also a value to your long term investment there.

Jeff
Yeah, how much of that is considered during the design process like the serviceability because, you know, suspension components are kind of unique. I mean, that’s one of the few things that like a lot of local bike shops are not set up to handle, because it is so complex, and there are a lot of special parts and tools that you need. So is there like a path to making this easier for folks or even just for local bike shops to do, or is this always going to be kind of like a specialized process for working on suspension?

Chris
So we’ve spent — and I think you can see this from our YouTube channels, how much energy we invest in making sure that there are the small parts kits, and the knowledge of how to work on the products is really widely disseminated. And if we go back to like the most common service that would happen, which would be like a lower leg service at 50 hours or an air can service at 50 hours, those don’t require you to go into the pressurized side of the system. It’s all on the unpressurized side of the systems. And it’s not trivial. But in terms of like technical know how it’s pretty straightforward stuff. And most mechanics could learn how to do it from watching a YouTube channel.

To be perfectly honest with you, the most important thing in either one of those processes is the cleaning aspect. So like making sure that before you open up your product, it is extremely clean, so that you don’t introduce contamination into the product. Make sure you’re not over torquing your bolts or under torquing your bolts. But you know, like that cleaning step is really kind of like the most important one there.

Jeff
Yeah, right it clearly requires an eye for detail. And that’s why you always see the folks wearing the rubber gloves and everything doing it because yeah, you need to make sure you’re keeping it clean.

Chris
I personally interact with a lot of mechanics at bike shops, and I have a high degree of respect for the level of know-how and like the interest that they have in learning more. You can imagine when I walk into shops, I get a lot of questions about a lot of things. And I always really, really appreciate those individuals, because they are taking advantage of every opportunity they can to learn more so that they can be better at their trade. And then members of our community, you know, like the bike shop employees or like people, a lot of times we’re building the trail or like out there making sure that the kids know how to ride their bikes safely and properly. Yeah, so for me, I think it’s, it is something that, like, keeps the cycling community going, as well as like, being a good, good way to maintain the value of your product.

Jeff
Yeah, for sure. And there are so many — and I mean, I forget too, right, I’m a mountain biker and I ride gravel every now and then — but you know, for me like biking is mountain biking. But you go into a shop and you realize like, oh, shoot, like there’s road bikes. I know nothing about road bikes, like there’s so much that they have to know and understand. And, yeah, suspension is just like one piece of one type of bike that they work on. And so yeah, hats off to bike shop mechanics for sure.

Chris
So I, I always chuckled to myself a little bit because I feel very comfortable working on rear shocks. I can take them apart, put them back together, it’s fine. I definitely still experience a bit of anxiety when I have to do handlebar tape. Which always makes me smile, right? Like I would be very nervous about doing handlebar tape for anyone other than myself.

Jeff
Yeah, right. I think it just depends on the person to like you said like, if you’re working on suspension, you got to be very clean and detail oriented. Whereas for other stuff, maybe you can be a little more ham fisted, and, you know, different strokes.

So finally, I want to ask you, which suspension innovations are you most stoked about, like new stuff that’s maybe already out or stuff that maybe could be coming in the future? Like, what’s kind of the big deal in suspension right now?

Chris
Yeah. So there are some things coming in the future. But unfortunately, I can’t talk about them.

Jeff
Yeah, but you’re really stoked about them. And we will be too I’m sure.

Chris
But the things like what we have access to today is is pretty amazing. You know, the two things that come to mind when you ask that question, one is Butter Cups, which we introduced with our MY 23 Rockshox product line. And I think that is an innovation that I really liked because I think it it just reduces a lot of hand fatigue and allows riders to push harder and further on a longer descent so that that one comes to mind.

And then the other innovation that I like, which is like very in the weeds, is the base valve that we developed on that Charger 3 damper which has a really specific oil flow path that reduces and it will actually eliminate the rebound noise in the fork damper. There’s a bunch of really cool, neat little features in there. And I still, every time I ride that fork and it’s quiet, it makes me smile. And then I also know like how much how much blood and sweat was expended to get to that. I think it was worth it because it creates a really good riding experience. Because you get to ride in silence.

Jeff
Yeah, right. I mean, what a great place that we are today where it’s the little things like that, that get us most excited. Because, you know, I mean, suspension it is really great. But there’s still these like areas where we can now take some time and be like, okay, like, can we dial this in? And can we like, make it quieter? Can we, you know, reduce these vibrations that have always been there, but nobody really thought like, oh, we maybe we should do something about this.

Well, Chris, thanks so much for taking the time to chat with us. I learned a ton. And actually, I mean, we had other stuff to cover, but ran out of time. So we’ll have to do this again. But thanks for thanks for joining us.

Chris
Yeah, I really appreciate the opportunity. And I hope this was helpful and informative and I’m down to do it again. Maybe you can get some feedback from the listeners on what they want to hear for round two.

Jeff
Yeah, that’s a great idea. So if you’re listening, and you’ve got questions about mountain bike suspension, definitely hit us up and let us know and we’ll be sure to send these over to Chris.

And also, check out the SRAM website schram.com and look up those YouTube videos that’ll help you get your suspension dialed in and hopefully answer any other questions you might have.

That’s all we’ve got this week. We’ll talk to you again next week.