Riding a bike is a pretty simple affair, but like with many things, technology marches on and adds complications. Where once all you had to worry about was pumping the cranks and shifting the gears, now a lot of bikes have front suspensions that need to be adjusted for different riding conditions. Great for efficiency and ride comfort, but a little tough to accomplish while you’re underway.
Luckily, there’s a solution to that, in the form of this active suspension system by [Jallson S]. The active bit is a servo, which is attached to the adjustment valve on the top of the front fork of the bike. The servo moves the valve between fully locked, for smooth surfaces, and wide open, for rough terrain. There’s also a stop in between, which partially softens the suspension for moderate terrain. The 9-gram hobby servo rotates the valve with the help of a 3D printed gear train.
But that’s not all. Rather than just letting the rider control the ride stiffness from a handlebar-mounted switch, [Jallson S] added a little intelligence into the mix. Ride data from the accelerometer on an Arduino Nano 33 BLE Sense was captured on a smartphone via Arduino Science Journal. The data was processed through Edge Impulse Studio to create models for five different ride surfaces and rider styles. This allows the stiffness to be optimized for current ride conditions — check it out in action in the video below.
[Jallson S] is quick to point out that this is a prototype, and that niceties like weatherproofing still have to be addressed. But it seems like a solid start — now let’s see it teamed up with an Arduino shifter.
Absolutely brilliant.
I could see this being either brilliant or terrible.
Unexpected suspension behavior is unsafe- from a handling perspective it affects turn-in, brake dive and balance. When dealing with terrain, we need predictable, consistent “squish”.
On the other hand, having stiff suspension is nice on road – pedal power is transferred into thrust more efficiently, and braking/turning is sharper.
Thoughts on improving this go a few ways – first, an obvious visual indicator of the suspension state is needed. Some bright LEDs on the handlebar, maybe? A manual way to ask the bike to unlock the suspension proactively would be nice.
The control algorithm would probably benefit from GPS data. One could make broad assumptions about proximity of a road and need of a suspension. One could also correlate position and accelerometer data to predict surface conditions.
Another thought on physical implementation- a servo is relatively slow in relation to suspension travel times. I’d love to see an implementation of magnetorheostatic shock absorbers to provide much quicker, more modulated control.
>When dealing with terrain, we need predictable, consistent “squish”.
The terrain doesn’t squish predictably either.
>an obvious visual indicator of the suspension state
You won’t be looking at it after a while. You shouldn’t need to be looking at any dials or indicators in the first place because it’s a safety hazard.
>The control algorithm would probably benefit from GPS data.
Inaccurate and slow; would cause unexpected glitches and false reactions. More annoying that its worth.
As long as the algorithm reacts consistently to shocks and vibrations, you will automatically learn how it behaves in what conditions, and will intuitively adjust your reactions to it. It is effectively modifying how things like pavement or gravel feels like to drive on, always the same every time without tricks and gotchas like getting a GPS reflection that makes the suspension think you’re off-roading now.
If there’s anything about the system missing, it’s the fact that it’s always coming two steps behind.
When you climb the curb with your wheel, you’d wish the suspension was soft – but the algorithm only turns the valve after the fact you’ve already hit it, and it turns the suspension mushy for a few seconds while you’re driving on smooth pavement. That can’t be helped without adding radars and whatnot, but those will cause glitches and unpredictable behavior.
>The terrain doesn’t squish predictably either.
You didn’t read what PEBKAC wrote. Having a fork that suddenly changes behaviour halfway through a corner is much worse than having a fork that’s not set up well. Predictable is almost always more important than better. If you can make the behavior change predictable then that’s okay, but that’s probably 80% of the effort.
That said, this is a system fitted to an SR Suntour mid-range fork. The use case isn’t the gnarly high-speed enduro trails, it’s tootling around the XC loop and having fun. For that, I think this system has a lot of promise and I’d certainly love to try it out.
It’s the same problem as automatic gearboxes: you don’t want the box to suddenly downshift in an icy corner because the torque change will throw you into a slide.
In critical conditions, you switch to manual, or invest in a car that also has electronic slip control. What would that mean in terms of the bicycle, I don’t know, but you can always turn the system off when you know you’re going to be making tight corners.
1990 tech.
I had a car like this. Sucked. The adjuster jams up and the shocks are quickly NLA.
But as long as the bike is a hardtail, not a big deal. Ideal bike suspension, for almost all applications, is your knees.
What if your knees are 1980’s tech?
I think that BMW had/has something like this with also uses a sensor in front of the wheels and an active noise cancelation algorithm. so it sensed the ground that the wheels were about to hit and tuned suspension accordingly. That’s not doable with software cause it’s too slow but I wonder if there is cheap hard for this now
Upper class Audi has such a system. Of course it relies on microprocessors with software – and some beefy (>1kW) brushless servos at the wheels which adjust spring tension
That would be adaptive anti-roll, not quite the same.
K2 had this on its shock back in the late nineties, Lapierre redeveloped it with its eShock and then dropped it, now SRAM (Rock Shox) has it on its ZEB for 2500EUR per kit.
I would say not worth it.
Having owned a Lapierre with e:i, I would say it was worth it. The system was great, did exactly what it said on the tin and overall definitely added something worthwhile to the bike. It was rear shock only though, but for the intended usage that was 90% of the performance gain anyway.
It also had flimsy mounts, wasn’t exactly waterproof and when the electronics inevitably died I couldn’t get replacement parts and had to tear it all off and replace the shock with a Cane Creek.
The worst part was honestly the exclusivity of it. If other manufacturers adopted it and parts were available it would be a great system.
I’d love to try a bike with the Rockshox system, as it adds the fork into the control mix.
I don’t need this on my fixie.
This comment reminds me at: “I do not need any horses for my hand drawn cart”. Of course you can stay stuck in the stone age.
Bicycles have been intentionally stuck in the stone age since Union Cycliste Internationale (UCI) banned recumbents from racing in 1934. WIth this, racing bicycles is effectively racing biplanes – entertaining, but not cutting-edge (except for the marketing puffery around new widgets or uncomfortable shoes). I’m sure someone will sell racing gloves for that carbon-fiber hand drawn cart in place of adding a horse.
Another example along these lines, but with an instructive end, are the America’s Cup racers, stuck in the 1850s until pried loose from the US’ East Coast yacht clubs (and their lawyers) in 1983, freeing competitive sailors from displacement hulls forever. The results of that evolutionary leap, blindingly fast and gorgeous to look at, are a lesson in letting evolution take its course.
Racing technology tends to converge towards a local maximum for whatever technology is feasible. Soon enough everyone is doing the same thing, and the technology itself becomes uninteresting – whether you’re racing airplanes, sailing yachts, or bicycles.
The only difference is that with highly optimized, highly specialized, and highly priced technology the barrier of entry is raised miles above what the general public could access, while the devices themselves – such as the racing bicycle – becomes totally useless otherwise.
Formula 1 for example is just a boring circus of which advertiser logo passes the goal line first.
Honestly it’s over-complicating (though I applaud the fun project). There are commercial offerings that do this already, from OEMs, but they were very pricey and the pros dropped them immediately and went back to dumb setups for predictability (I assume). However there’s really no need at all, a manual lock-out for road use, and a well tuned fork for the rest of the time will cover 99% of usage, and any decent suspension fork has speed sensitive damping already based on the damping force applied and spring loaded valving in the piston. I have literally never touched the damping on my fox 36’s after their first setup, other than to adjust slightly for my body weight increase, and they function wonderfully on all surfaces, if a little too plush on road climbs :D
> if a little too plush on road climbs
That’s exactly what this is intended to solve, right?
But more generally, it’d sure be cool if this thing could say oh you’re on what google maps identifies as a paved road, full front and rear lock-out, oh you’re not on a road, normal suspension settings.
And for those of us who don’t have handlebar controls (front fast and slow compression, fast and slow rebound, rear rebound and fast and slow compression, seven different things to adjust) having something doing that for us would be kinda cool and way better than trying to mess around with the little levers on the rear shock mid-race. (It looks like, at least right now, there aren’t any UCI rules against active suspension.)
What we’d really like, of course, is to have this adjust SPRING stiffness, so it’d crank the spring stiffness up to max on paved sections and then run it down to the right sag for offroad, and don’t even mess with trying to stiffen up the ride via compression settings. But it would be neat to have something that can increase slow compression way up on smooth sections, and maybe vary slow rebound in concert with slow compression.
Very interesting idea, but wouldn’t automatically adjusted rebound damping be more useful? Just the little dial on the bottom of the form. I could actually see that being really useful. On smooth faster sections of trail it could turn rebound up so the fork is springer and more responsive but when it starts detecting bigger impacts from roots or drops it could lower the rebound to absorb impact better and keep the wheel on the ground
It’s kinda the same problem as with Formula 1 racing. The machines have become so specialized, optimized and esoteric that they just aren’t interesting anymore. Over time they all just converge to the same winning solution and all the vehicles look exactly alike. At that point, it doesn’t matter whether you use those highly optimized machines, or one of those cigar-shaped death traps from 1950. As long as everyone is doing the same thing, it’s the driver that makes the difference.
So with the bicycles as well. If you allow recumbent bikes and other mods, well, two years later everyone has a recumbent because you can’t win without. The racing cycles would become highly technical and completely disconnected from what anyone would drive on the street, and the bar of entry to the whole sport would become elevated to the point of irrelevance.
This was posted in reply to Thinkerer: “Bicycles have been intentionally stuck in the stone age…” but erroneously bumped here.