Syntace, Liteville and Canyon are together launching a concept they call KIS (Keep It Stable), which uses a spring to "stabilise" the bike's steering by applying a carefully designed force which acts to pull the front wheel towards the straight-ahead position. This is designed to counter a force called wheel flop, which acts to pull the steering away from centre. We've all experienced this on a slack bike at low speeds, where the handlebars feel like they're steering on their own accord away from straight ahead, leading to wandering steering. The system is also claimed to make the steering less twitchy, more weighted and more predictable.How does it work?
One thing to make clear is that this is not a steering damper. Those have been tried before and seem to be mostly not appropriate for MTBs, where speeds are slow and rapid changes in direction are required. This is a steering spring, which exerts a torque on the steering assembly (the front wheel, fork and cockpit) which depends on the steering angle
- the angle of the front wheel from the straight-ahead position. The further the steering assembly is turned away from straight ahead, the higher the spring force (torque) is acting to pull it back towards the centre.
It does this with a pair of small springs anchored in the top tube, which connect to the fork steerer via a pair of kevlar bands connected to a cam wheel clamped to the steerer tube. As the bars are turned to one side, the springs are stretched, creating a force in the opposite direction. The geometry of the kevlar bands and the cam are designed to give the torque curve below, where the restoring torque increases quickly as the steering angle moves away from straight ahead towards about 15 degrees, then increases more gradually to make it easier to negotiate tight turns without feeling restricted.
This torque is designed to counteract the force created by a phenomenon called wheel flop
. If you stand your bike upright with the steering off-centre, the handlebars will naturally turn away from straight ahead, towards a steering angle of 90 degrees. This is because, as the steering angle increases, the bike frame (and with it the rider) drops towards the ground - by over 10 mm in the case of a slack bike.
To picture this, imagine a bike with a 0-degree head angle (a horizontal fork). Now as you turn the handlebars away from straight ahead towards 90 degrees, the head tube would drop towards the ground by the radius of the wheel. With a vertical head angle, the head tube wouldn't drop at all. So the slacker the bike's head angle, the more the head tube will dip as the bike steers.
This drop in head tube height creates a force which acts to pull the steering away from straight ahead. This is a destabilising force because (within the range of normal steering angles) the further the steering moves away from straight ahead the more force acts to pull it even further away.
The KIS system is designed to compensate for this, making the steering assembly more stable and less prone to pulling to one side.
At the risk of complicating things too much, we also have to talk about trail
. This is the distance by which the tire's contact patch sits (or "trails") behind the steering axis (the line about which the steering assembly rotates as you steer).
Just like a trailer being towed behind a car, the contact patch is effectively towed behind the steering axis, which causes it to naturally fall into line behind it. This creates a self-centring force which counteracts the wheel flop force, and overcomes it at higher speeds. This is why the seeing on slack bikes feels stable at high speeds but unstable "wandering" at low speeds. The effect of the KIS system is to provide an additional centring force which operates at all speeds, making the steering less unstable at low speeds and even more stable at high speeds.
The wheel flop force is dependent on the amount of weight on the front wheel, so the system offers an adjustment mechanism to tailor the amount of counter-force it provides to suit rider weight and personal preference. This is done with a slider which changes the preload on the springs.
In terms of practicalities, Canyon's system weighs a claimed 110 g, and Liteville's a little less. It requires no maintenance and uses a regular fork which can be removed or replaced by undoing the bolt on the cam, which in Canyon's case is accessed via a port on the left side of the frame. At the front of the head tube is a stop screw which prevents the cam ring from turning past 90 degrees. If the handlebars are forced beyond this angle (in a crash, for example) the cam ring will slip on the steerer. When this happens the system needs to be re-set (like straightening a stem) or else the mechanism will pull the steering towards one side.
For now, Canyon are launching just one model with the KIS system, the Spectral CF 8. Canyon say they chose this model because it's their best-selling bike, and they wanted it to be available to the largest number of buyers. The system has been tested on downhill bikes, and even saw action at the Fort William World Cup under Mark Wallace, though only in practice. Canyon say they plan to "roll out K.I.S. across many other models in the future." Liteville have one ebike with KIS integrated: the 301 CE EMTB.
Pricing for the standard Spectral CF 8 is £4599 (4599 EUR) and the K.I.S. equipped bike is £4999 (4999 EUR). It's due to land in the USA in Spring 2023. You can't retrofit KIS to another bike but the system can be removed and blanking plates will be available next year.
I was able to try out the system with a day of uplift-assisted riding on the Canyon Spectral, followed by a ride on the Liteville 301 eMTB the following day.
The first thing I did was carve some turns in the parking lot. Though it feels odd at first, it's very easy to adapt to the system in this case. But riding with no hands on the bars is very difficult. Normally when you lean to the left without touching the bar, the steering assembly turns to the left due to a combination of its own weight, wheel flop and gyroscopic forces, and this steering causes the wheels to move back under the rider's centre of gravity, correcting the lean and keeping you upright. But with KIS, the steering stays closer to straight ahead, so the bike is prone to falling over (known as capsizing). So while the steering
may be more stable in terms of self-centring, this doesn't necessarily make the bike more stable in the sense of remaining upright.
But what about on the trail?
Again, it's easy to adapt to the system on the whole, but there were times when something felt a little odd. I found myself running wide in turns at times, especially with the system's tension turned to the max. It's not that I couldn't turn the steering to the angle I needed to make the turn (the force is quite modest), but the subtle counter-steering needed to initiate a turn required some recalibration. In order to turn left, you first have to steer to the right (counter-steer) so the bike becomes unbalanced and leans to the left; only then can you steer the bike to the left without falling over. I think with KIS engaged (especially on the max setting), I wasn't counter-steering enough and so not leaning enough, so I had to brake in the turn or adjust my steering mid-turn to get around.
Of course, this is something you get used to the more you ride it, but when I switched back and forth between the system's maximum, middle and minimum torque settings on the Spectral, I consistently preferred the minimum setting. I found it easier to make tight corners and stay balanced. Even on high-speed rocky straights, where I expected the bike to feel more surefooted and easier to handle with KIS, I sometimes found my weight in the wrong place and felt slightly less balanced with the maximum preload. I think the constant micro-corrections needed to maintain balance were muted, making it slightly harder to feel poised on top of the balance point.
Similarly, on the LIteville eMTB, I rode some awkward turns and narrow bench-cut trails and felt less able to correct and stay perfectly balanced with the system on when compared to off (the Liteville demonstrator could be switched completely off). When I came to some exposed switchbacks towards the end of the ride I kept the system switched off because that felt safer to me.
Don't get me wrong, the downsides are subtle and easy to overcome with practice. There are some upsides too in that the steering feels more weighted and settled, especially on low-speed uphill switchbacks where there is less wheel flop, but I noticed the downsides more than the upsides. Jo said it takes a long time to fully get used to the system and I'm sure with more time on it I'd adapt to the different forces required at the handlebar to ride smoothly. But the dilemma with testing any new technology is that once you get used to it, you've become unfamiliar with riding anything else. For example, I once cycle-toured for a week on a road bike with heavy panniers; when I took them off, I remember the bike feeling horribly twitchy for the first minute or so. That doesn't mean the handling with paniers was better, just that I preferred what I had become used to.
And while the system reduces the rider input required in some situations, like tight, slow switchbacks, it takes more effort to stay balanced at speed or throw the bike into tight turns. I'm sure that if I'd ridden with KIS for a long time (months or years), a bike without it would feel weird. But it's not clear to me that the system is making the bike easier to handle, as opposed to just different.
Fabien Barel described the system tying the front and rear of the bike together, making it easier to correct front-wheel drifts. He might have a point, and it will be interesting to see if any Canyon athletes use it for racing next season. But from my (brief) time on the KIS system, the benefit is hard to discern.
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