Shimano have created a system for electric bikes which combines an electric motor with their own Di2 electronic shifting.
It has the most advanced control and display system we have seen. It also has the option of manual control or fully automatic shifting using the 8 speed Di2 hub gear which gives you absolutely smooth and seamless shifting and pedalling with plenty of help up the hills.
STEPS stands for Shimano Total Electric Power System. It's a pedal-assist system, which means the power is only applied when you're pedalling. This makes the bike feel very much like a normal bike, but with a maximum torque of 50nm power when you need it.
EU and UK regulations state that the power output must not exceed 250 Watts, and that the maximum assisted speed will not exceed 25kmph (15.5 mph). That means that if you want to go any faster you will be doing all the work yourself, which has the odd effect of feeling as if you have pulled the brakes on. This is true of all power assist systems and makes them great for pulling away and getting up hills, but they won’t necessarily go any faster overall.
The drive unit is mounted on the bottom bracket and according to Shimano, weighs 3.2kg, making it one of the lightest on the market. There are a number of sensors incorporated into the unit to monitor torque, cadence, braking and speed. The battery has a 400W-capacity lithium-ion battery, It takes four hours to give the battery a full charge but only two hours to fill it up to 80 percent. Shimano claims the battery will last 1,000 charge cycles, which should be around 37,000 miles of riding, although this will depend on how much you use the power assist. The STEPS battery can be charged on or off the bike and a new one currently costs around £600.
The chainset has either a 38 or 44-tooth chainring and and comes with a chainring cover to keep your clothes clean. With the Di2 8 speed Alfine hub-gear set-up you can choose either a 'manual' setting and change gear by pressing buttons, or go choose the 'automatic' option and let STEPS decide when to change gear for you. The automatic setting uses a 'Symptomatic shifting system' that senses your cadence and power output, and shifts gears to match them. You can fine-tune the system's sensitivity so that the shifting occurs at specified cadences. When you stop at traffic lights it will automatically shift down so that you're in the right gear when you set off again. A further nice feature is the integration of the lighting system which is powered from the battery.
The display that shows all the usual information you'd expect from a bike computer, including speed, trip distance, elapsed time, as well as which mode the STEPS system is currently in and what gear you've selected. It also uses the data you have generated on previous rides to estimate the range left in the battery.
We are die hard cyclists but we recognise that there are many people who want a bit of extra assistance, and the STEPS system is the most sophisticated and comprehensive system we have yet seen.