[Automatic] Variable Stem for Human-Powered Vehicle by Shimano

In this article, we’ll be discussing a Variable Stem for Human-Powered Vehicle by Shimano, US patent 11034407. The publication date is June 15th and the filing date is Nov. 14th, 2018. This has been granted

This will be a short article because I’m hella busy (bringin hella back), but I wanted to get this out there because it’s interesting.

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Brief Summary (tl;dr)

Shimano are introducing a variable stem, which can be controlled both manually and automatically. In the first example, the stem has a manual unlocking system with a handlebar-mounted level to pull a cable and unlock the stem. The rider can then place the stem in the desired position and lock the stem in place. The next is the exact same stem, but with an electrical actuator to unlock the stem from the handlebars. So, it’s just a button. Lastly, the most interesting part is the completely automatic-positioning stem. There are two configurations to the automatic stem. The first is pseudo-automatic, where the rider can manually adjust the stem based on what the rider visually sees in front of them (for example, uphill = stem down). As a result, the suspension will automatically recognize the rider wants to go uphill and will lock the suspension. And it’ll do the exact opposite for downhill. The second configuration is fully automatic. The bike has sensors, a controller, and the stem has an actuator. When the bike recognizes it’s going uphill, the stem will automatically lower and the suspension will lockout. Again, it’ll do the exact opposite for downhill. So, this is an active stem. Active everything, fuck it.

Intended Novelty

The intended novelty here appears to be the use of a controller to move the stem. The controller can be both manual and automatic.


Shimano say this:

By changing the position of the stem body according to the change of the gradient (vehicle inclination), the riding position can be kept properly, and at the same time, stable running can be realized by automatically controlling the effect condition of the suspension dampers of the front and rear suspensions.

This seems way out there and unnecessary, but Shimano have the time and money so they’re doing it. And, if they feel they can make some money with it, they’ll do it harder. Ultimately, this might just be a protective patent for like 10 years from now. If they don’t do it, someone else will. It’s honestly scary how many patents Shimano releases every week.


I’m going to skip the minutia of the mechanicals inside this thing because it really doesn’t matter how the actuators/motor/gearing is setup. All we need to know is the end result and how we get there.

FIGs. 2 and 3 show the system in all it’s glory. The first thing I noticed is are the three little buttons next to the grips. I’m assuming that’ll be shifting, suspension, and dropper controls, based on other documents I’ve read.

So, there are a few different examples in this document. The first is a handlebar-mounted lever to manually operate the stem, which can be locked and unlocked by lever 16 in FIG. 2 and 3. This uses a traditional cable 18 to release a locking system so the rider can put the stem in the desired position. FIG. 5 below shows the cable and locking system. Pretty simple. This is the primary idea here.

The next idea is shown in FIG. 12. Notice how the handlebar-mounted switch is now a little button 116. Next, notice actuator 115. So, that little button actuates the electrical actuator to engage the manual locking system, as shown prior in FIG. 1. This system is almost exactly the same as FIG. 1, but the manual lever is replaced with an electrical actuator.

Lastly, the third idea is the most interesting. This is where we have sensors, a controller, and an actuator. Have we heard this before? What do those three things make? Fucking active shit, that’s what. So, this third idea is an active stem, which can detect bike position and orientation and automatically adjust the stem to a predetermined position based on what the computer thinks you’re doing.

…the variable stem 210 can be automatically adjusted based on a driving state of the human powered-vehicle B…

FIG. 13 shows this automatic stem. See those little gears? Those are controlled by the motor and actuator and raise and lower the stem for you.

…the variable stem 210 comprises an electronic controller 214 and an electric actuator or motor 215 for controlling the positions of the variable stem 210.

But, there is an override to this stem, and can be controlled manually, as well, using the motor.  

…the component control which the variable stem 210 can be manually operated by a rider while the human-powered vehicle B is in a driving state…

FIGs. 15 – 17 show an example scenario of the rider controlling the bike’s components. The system allows the rider to adjust the stem (and suspension) based on what the rider visually observes themselves. So, if the rider is going down a hill (FIG. 15), they can set the stem to the highest position. As a result, the suspension will open up for the sick downhill you’re about to do.

The rider can also set the stem to an intermediate position for flat-land stuff (looking at you, Florida). Again, the bike will know the stem is in an intermediate position and set the suspension accordingly. Shimano notes the rear will be firm, and the front will be set to a medium setting.

The rider can also set the system to a climb mode. The rider sets the stem to the lowest position, and the bike will know to adjust the suspension to full-firm mode.

Now we’re getting into the fully automatic part. FIGs. 18 – 20 show the automatic system. In FIG. 18, the bike is going downhill, so the system knows to set the stem to the highest position. In turn, the system will also know to set the suspension to fully open, as noted above.

FIG. 19 and 20 then go on to show an intermediate position and an uphill position. Again, the suspension will automatically adjust as well.

This idea goes even further and adjusts the stem based on other inputs. First, the stem can change positions based on weather or rain:

In normal or rainy weather condition, it is preferable to have the normal stem position. But in a windy condition, if the resistance from the wind is strong, it is preferable to have normal or lower stem position for balance and to avoid the resistance. In some case, if the wind is blowing from backwards, higher stem position is sometimes needed in order to use the resistance to make the human powered vehicle B is moves faster, and number of pedaling also can be reduced if necessary.

Road conditions:

The stem position can be adjusted in accordance to the rider preferences while riding on a certain route/surface condition, and the next time the user rides the same route/surface condition (based on the GPS location), the settings can be adjusted automatically to where the rider had previously set them.

Reciprocal seat/stem position:

The adjustment between the stem position and seatpost height is similar to the adjustment of the suspension and the stem position. It is also preferable to have the seatpost, suspension and the stem position adjusted in accordance to condition of each other.

The stem can also be adjusted based on a E-bike motor, brakes, and fitness tracker. It can also include a headlight, and can adjust the headlight position based on everything we’ve already talked about.

Lastly, all of this info can be sent to a cycling computer and provide real-time stem-position information to the rider. Why would you need this? Eyes on the road, bro.


Just what we need, another switch on our handlebars. Could you imagine this on a Scott?

There are obvious issues here, like the stem snapping in half. I feel like that’s a real concern with any adjustable or damping-style stem. That being said, I’d be really surprised if this is ever marketed toward any person that does rowdy downhill tracks. I can definitely see this as an XC-type device, although they would then have to combat the weight-weenies to get this on their bikes.

There a lot to unpack here. All we need to know is: automatic stem moves based on bike position.

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