ELECTRONIC SUSPENSION Getting to grips with hit
For those not initiated into the dark ar rt of suspension setup, electronically alter red pogos could well be the tech you’ve spent yo our life waiting for. But is it really as good as it’s madee out to be, how does it work, and will it make you u faster?
Computers: they’ve taken over just about everything in our lives nowadays. Music, television, photography, pornography – it’s all now ruled by LCD screens and silicon chips. And generally, it's made things much better all round (especially the pornography, or so they tell me). Cheaper, faster, better, easier. They’ve taken a while to make big inroads into bikes though. Up to about ten-fifteen years ago, you could still buy a new bike with stubbornly-analogue carburettors, but since then emissions rules have meant that almost every bike has come with a fuel injection system, which includes a little computer. That was pretty much it till recently though – a fuel injection ECU, maybe an ABS control box, and a digital clock in the dash. Not exactly Tron, is it?
But over the past few years, that’s all changed. Firms like BMW and Ducati in particular, have now got integrated computerised systems that manage many of a bike’s functions. Traction control, power modes, wheelie and launch control – a top-level superbike now has all of these, letting you customise the engine’s output to your precise demands. Lovely.
What about the chassis though? Well, ABS is a contender of course – and these smart systems are increasingly part of the overall system, using the same wheel speed sensors, dash display and controls. But the last part of the picture is suspension. Having a computer look after what’s going on with your forks and rear shock is the obvious next step. And it’s happened already, on a few high-end models. But what’s the point of electronic suspension? And how can it make you faster?
Wa ay back when
We ll, there are a couple of basic things we nee ed to realise about electronic suspension syst tems at the moment – and for the near futu ure. Firstly – they’re not always just about performance. The first electric suspension adjustment systems arguably appeared in the earl ly 1980s, on Honda’s behemoth Gold Wing ng megatourer. Thee two-wheeled pantechnicon came with an on-board air compressor on certain models, and at the push of a button it could increase the pressure inside its air-sprung shocks and forks, stiffening up the suspension for a pillion (or a topbox full of Beajoulais after a Calais booze cruise).
BMW was next to come up with electronic adjustment, on the 2004 K1200S and R – and it was quite a bit smarter. The firm’s ESA electronic suspension adjustment system had a series of presets on the dash readout, which you cycled through, for solo, two-up, and/or luggage setups. The ECU used small electric motors to turn the adjusters on the shocks (rear and Telelever front), giving stiffer damping and (on some versions) altering preload and even spring rate. The point here was convenience, and ease-of-adjustment for differing loads. On a Gold Wing or similar, the shocks and forks are hidden under loads of plastic panels, and are tricky to access. And unlike on a sportsbike, you can very easily add over 100kg for a ride, if you fill the panniers and topbox, and throw the old handbrake on the pillion seat. So – there’s more need for radical suspension setup changes, and they’d be a real pain without an electronic system. Replacing the C-spanner and screwdriver from the toolkit with some neat push buttons is the perfect solution, for a high-tech, luxury touring bike.
Smarter tech
That’s one type of electronic suspension adjustment, the most basic setup, and one which has extended out into a range of bikes. It’s not very clever though: once the computer has moved the damping adjusters, it’s finished. There’s no change in the settings as you ride along.
The next step, then, is to smarten up the adjustments. Wouldn’t it be great if you had a MotoGP tech to adjust your forks and shock for each ride, taking into account where you’re going to ride, and how fast you’re feeling. What about if our suspension engineer could set you up for every corner? A crazy notion indeed (just think of the cost in strip clubs and hotel minibars to have a race tech follow you around).
But that’s what the very latest semi-active electronic suspension setups are aiming for. A super-smart computer ECU sits under the seat hump, and it gets access to all the info on what your bike is doing. How fast, what gear, whether you’re wheelying or not, how hard you’re braking; it all comes in from the engine ECU and ABS computer, plus the IMU inertial measuring unit. Then, together with whatever base setting you put into the bike when you set off, the suspension ECU operates electric motors or solenoids, which move the damping adjusters in and out.
This lets the ECU select more, or less, damping, or compression and rebound, in order to give the perfect damping setting for that bike, at that moment, doing whatever madness you’ve dialled in with the throttle and brakes.
Supposing you’re hard on the brakes at 150mph at the end of Silverstone’s Hangar Straight; with a track-friendly riding mode engaged, the ECU will know what’s coming, and will be readying more compression damping in preparation for some unholy anchorage. Likewise, when you’re pootling home in top gear at 30mph through a village with a less focused map employed, the adjusters will be winding everything back so you can waft along like you’re Driving Miss Daisy.
It’s a beguiling notion – and this state of the art ‘semi-active’ setup is now surprisingly common across a load of bikes. Ducati’s Multistrada and Panigale have it, all of BMW’s big bikes have it as an option, KTM offer it on their Super Adventure S, and the 2017 Honda Fireblade SP has a smart Öhlins setup, as does Yamaha’s R1M. And, for 2018, Kawasaki have released an all-new Showa electronic suspension system on their ZX-10R SE.
Everybody’s at it
Contrary to that last paragraph, not that long back electronic suspension was about as common as trench foot is to office workers; no one had it. But then the Munich massive (BMW) kicked things off by fitting its electronic suspension system (ESA) to the R1200 GS and K1200S way back in 2004.
The Germans’ second generation of the system (ESAII) was brought to life in 2007, and found a home on the K1300S. But it wasn’t until 2013 that BMW really upped its game, by bringing out its smarter, semi-active Dynamic Damping Control setup on the HP4 megabike in 2013. That was the first time the suspension actually adjusted according to feedback from spring stroke sensors, as opposed to just altering to predetermined damping positions. It was a huge breakthrough that set the standard for the industry using a cunning elastomeric spring rate adjuster. This moves a steel sleeve in and out of a rubber-like material, which actually changes the effective spring rate of the monoshock. Moving the sleeve out of the elastomer makes it ‘softer’, lowering the overall spring stiffness. This is different from preload adjustment, and before ESA, could only be done by actually swapping out the metal spring itself. Clever stuff. KTM, the Austrian purveyor of twowheeled nuttiness, also has an electronic suspension system, produced by its in-house suspension firm, WP. The forks and shock units themselves are built by WP, and the system uses Bosch’s electronic control unit, with software calibration by WP. Its semi-active suspension is fitted on the Adventure S (since 2015), and was also on the original 1290 Adventure. The 1190 Adventure also came with electronic pre-load
adjustment from 2013-16. It’s not just for the adventure bikes though: the orange loons bolted electronic suspension onto their crackers SuperDuke GT as well, which has proven a winning combination.
Like all fashions, electronic suspension has left many wanting a slice of the action, and in 2018 it will be Kawasaki’s turn to step into the electronic suspension arena, thanks to Showa and an exclusive deal between the two companies. The 2018 ZX-10R SE features an all-new semi-active Showa electronic suspension system. We saw the bike at Milan last month, and chatted with some senior bods at both Kawasaki and Showa about it, and it’s a pretty impressive setup. Both the rear monoshock and the front forks have computer-controlled damping adjusters, but they use a new solenoid-type adjuster. Much current tech uses small stepper motors, connected to the damping screws, so a little 12V motor does the job you would do with a screwdriver on manual suspension, dialling in more or fewer clicks. But Showa uses a solenoid – an electrical device that moves in and out in a linear fashion – to operate the damping needles. This is a faster, more direct mechanism, and it reacts in milliseconds.
Showa’s also fitted its new units with stroke sensors – small electronic devices to measure how the suspension is moving. That’s then fed back to Showa’s own ECU, so the computer knows where the wheels are in their movement range, how fast they’re moving and whether they’re accelerating or decelerating. That info is combined with other inputs from the ZX-10R’s main ECU covering speed, throttle position, braking – and it also looks at the bike’s IMU unit, which tells it about the bike’s lean angle, and also its pitch and yaw.
In theory, the new SE should have one of the smartest suspension setups around when it’s released next year. But for how long will it be considered cutting edge, and what’s likely to supersede it?
What’s coming next?
Well, there’s a hint of what’s to come with the new aforementioned Showa system actually. Many of the current ‘dynamic’ electronic suspension systems are smart – but not that smart. They adjust the suspension based on a number of factors – speed, throttle position, gear, braking – but they’re missing a vital engineering concept called ‘feedback’. That’s to say, they don’t know
exactly what’s going on with the wheel, because they don’t have a position sensor on the damper.
You’ve probably seen these types of sensors on race bikes, where they’re used for datalogging. Called LVDTs (linear variable differential transformer), these long thin devices look a bit like a skinny steering damper, and they measure where the wheel is in its travel, storing the measurement so that race techs can look later to see what the suspension was doing at each point on the track.
Now, if our electronic suspension system had these, it could immediately see what’s happening at the wheel, rather than having to interpret it from all the other factors. It could also see how fast the wheel is accelerating, and at what point in its travel it is. With a quick enough ECU and super-fast-acting damping adjusters, it could react much faster and effectively to bumps, braking and accelerating than ever before. The Showa setup on the new ZX-10R SE actually comes with just this kind of setup: stroke sensors in the shock and fork, and a new, solenoid-based damping adjuster mechanism, which promises to react in milliseconds. In theory, it should move the whole game on another big step.
So there you have it. Computers: they’re not just good for watching Game of Thrones boxsets and surfing the net for cat photos; they’re all set to make your bike handle better than ever on road and track, with bags more comfort and grip, in virtually all circumstances. If you knew little more than those qualities, it’d be hard to argue against incorporating those qualities. What’s a little harder to embrace is the cost of such tech, but that’s one for you and your wallet to scrap it out over.
Why not fully active?
You might have noticed that we’ve been using the term ‘semi’ in this piece, as in ‘semi-active’ suspension. So what would ‘fully’ active suspension be like? And would it be better? Well, bizarrely, a fully active suspension would be nonsense on a bike. What fully active means is that instead of the wheel movement being controlled ‘passively’ by a spring and damper, the suspension system itself would move the wheel, to perfectly match the road below it. So if a bike is about to hit a speed bump, then we need a powered actuator system to lift the wheel up and over the speed bump, perfectly matching the path of the wheel to the shape of the bump. Similarly, if we come up to a pothole, our active suspension system would push the wheel down into the hole, and lift it up again on the other side.
To do this, you’d need some way of measuring the road coming up in a millimetre-perfect fashion – perhaps with radar, lasers, cameras, or a mystic leprechaun trapped inside a suspension ECU box. Then, you’d need a hydraulic ram, or an electric motor-driven arm, which could move up and down, with great precision, at the massive speeds needed to perfectly track the road.
It means huge amounts of weight, complexity and power – all of which rules it out for bikes.
The racer’s choice
It’s all very clever stuff but even if weight weren’t an issue, why is it that racers aren’t drawn to the tech like proverbial moths? The truth is, high quality race bike suspension, setup properly for a smooth, predictable racetrack, with one skinny racer on board is a fairly consistent problem to solve. Okay, the techs could no doubt get a slightly better setup for each individual corner with electronic adjustment.
But would it make up for the extra mass, cost, complexity and setup time needed? Maybe not. It’s moot anyway, because the rules are stacked massively against electric suspension setups. In WSB, they can only be
used if they’re on the homologated bike – and, crucially, you can only use that homologated setup, as it comes on the bikes, with no changes to the ECU or the units themselves (apart from a re-valve and fluid changes).
You’re not allowed to use GPS or any other track position information in the suspension ECU either – meaning, you can’t have a setup that changes the settings from the straights to the corners, or that dials in a different damping solution for each bend. So that means they’ll be having to race a bike with added weight, you’re stuck with the road bike system, and wouldn’t be able to tweak it specifically for racing. Can you see why you might not bother?
In MotoGP, it’s even simpler – no electronic suspension is permitted in any class. Bosh.
Why are the authorities so against it? Well, it would be another massively pricey area for manufacturers to get het up about, and you can see how it would let the big teams pull even further away from the little guys. Will that last forever? Well, if the manufacturers spend more and more cash developing these systems, they might well start to push for them in the race world. The whole point of racing is, after all, to sell more bikes. So, proving your super-smart semi-active suspension on your MotoGP bike of a Sunday would certainly make it more desirable on the Fireblade, R1 or Panigale you’re trying to flog on the Monday. Right now, we can only presume, but as electronic suspension continues to expand its ever increasing footprint, with more and more manufacturers doing their best to have a slice of the action, we can only assume it’s a case of ‘when’ not ‘if’ we’ll see Rossi and Co. doing their business on automatically adjusted pogos. And as for the streets, we reckon it’ll be the norm in a decade at most. Maybe we’ll be wrong, but a fiver says we’re not.