Prototype Shimano eMTB rotor concept becomes new STePS integration

Written by Cory Benson Jul 07, 2017 10:30 a.m. ET

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It started out with Shimano engineers just trying to simplify & better integrate their fast-growing XT-level E-8000 STePS e-bike drive setup for mountain biking. While the bulk of the system is the bottom bracket mounted drive motor, a downtube mounted battery, and the electronics that run internally to a bar mounted display/controller, there still has to be the rear wheel speed sensor to keep everything in check at the 25km/hr pedal assist limit. Up to now that has left a speed sensor attached mid-way on the chainstay and a conventional wheel magnet attached to the spokes. Shimano techs realized that all these new e-bikes were getting disc brakes and with a little planning they could tuck a lower profile speed sensor into the dropout and put the magnet on the rotor for a much cleaner solution, better protected from trail hazards. We’ve got a look at Shimano’s simple prototype and now the finished production solution coming soon. Plus they’ve added even more integration opportunities with new light accessory connectivity, new remote switch & more…

The speed sensor integration was a really simple idea, and more than anything just required a new low-profile sensor design that could be mounted close to the dropout and get fully routed inside the frame. This prototype we previewed was literally just a powerful magnet glued onto a standard rotor, but Shimano has taken it a bit further for the production rotors.

Two eMTB specific rotors will be offered, the XT-level EM800 rotor with IceTech sandwiched alloy core construction, and a XTR-level EM900 rotor that adds on Freeza alloy cooling fins and a lighter spider as well. Both versions get a removable magnet that attaches to the backside of the aluminum centerlock carrier.

Both rotors will be available in both 160mm & 180mm diameters.

Then to actually track the rotation of the magnet-equipped rotor, a new low-profile sensor (SM-DUE11) will bolt onto the inside of the non-driveside chainstay and can be routed internally back to the drive motor & controller. The new speed sensor is compatible with both STePS MTB (E8000) and Shimano’s lighter-duty E6000 e-bike systems.

Cory Benson

4,481 articles

Cory Benson is the EU Tech Editor of Bikerumor.com.

Cory has been writing about mountain bikes, enduro, cyclocross, all-road, gravel bikes & bikepacking for over 25 years, even before the industry created some of these names. Prior to Bikerumor, Cory was a practicing Architect specializing in environmental sustainability, has designed bike shops & bike components, and worked as a bike shop mechanic.

Based in the Czech Republic for 15+ years, he is a technical mountain biker, adventurous gravel rider, and short & medium-haul bikepacker. Cory travels extensively across Europe riding bikes, meeting with key European product developers, industry experts & tastemakers for an in-depth review of what’s new, and what’s coming next.

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Bmx

7 years ago

D*mn thought this was going to be some weird induction cooled rotor from the future

bart

7 years ago

nice way to ensure all Steps bikes don’t get other brands parts on them.

bedampft

7 years ago

Reply to bart

Why is that?
Nothing up there is a must have.

FFM

7 years ago

Hot glue a magnet to your rotor and mount your existing sensor near the caliper and BOOM same thing but it works on every bike ever for free.

Omar

7 years ago

Why not just magnetise one of the rotor bolts, and incorperate the sensor on the brake calliper.

john

7 years ago

Reply to Omar

What if you have centerlock rotors? But mainly because the caliper is nowhere near the rotor bolts.

Mortimer

7 years ago

Hmm, 25km/h limit! Software hack and we could have it assist only over 25km/h. Yes, it is a motorbike!

Person

7 years ago

Reply to Mortimer

You’ll burn up the motor adding a signal splitter and it’s easy to pull data from the bike to see that is has been done. You can tune a car and take off a speed limiter and kill your warranty. People that want a faster Ebike either buy a speed pedalec or have a mid drive kit installed that you can program. You’re not wrong, but you’re also not the intended demographic. We sold the STEPS bikes to people fine with going 20 miles an hour and commuting on the bike. They have no throttle so at most it is just a moped. It’s just a 250w motor, so pushing that thing above 30 is going to blow the motor. A shop won’t break the law for it and Shimano won’t warranty your motor with the information showing that there has been a modification.

-1

Papi

7 years ago

Reply to Person

Honestly, it’s much more simple than a signal splitter. All you’ll need to do is unbolt the speed sensor and move it to the outside of the chainstay, and add a cadence magnet to the left crank arm. The computer will then understand the rider’s cadence as the rear wheel speed and assist until, well, forever. I don’t think you’d ever get to a cadence that would match the RPM’s of a 26″ wheel traveling at 25KPH, though math is not my strong suit so I could be wrong here.

Your point about burning up the motor is probably valid, and your point about riders who buy STEPS 250w bikes being content with 25kph is most certainly an accurate assessment based on those STEPS riders I’ve met.

7 years ago

E-bikes could be the holy grail of urban transport, but despite their simple parts they are still expensive when their price exceeds many mopeds

Mike D

7 years ago

Reply to S

Fantastic point about the mopeds–80 miles per gallon is not unheard of. With pedal assist the idea of ‘getting exercise on your commute’ becomes mostly bogus anyway, so why not get a proper moped?

John D

7 years ago

Good point about the cost. I’m considering buying an ebike but the cost isn’t proportionate to the cost of more complex transport options. I can buy a brand new small car for $14,000 or an ebike for $3500 with a reasonable component level. The aggregate cost of parts and labour to produce 4 of those bikes would be far less than the car. I like them but the cost just seems to be too inflated.