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Ask Optibike!: What's the deal with "boost", eco mode, and FAST mode?

The question is:

“I’ve noticed the best way to climb moderate hills in Eco mode is to
make rapid upgear changes probably every couple of seconds so as not
to let the bike settle into the low-power state before you get to the
top of your descent.

When does the bike change to the low-power state in Eco mode? Is the
duration of the boost phase constant or does it change according to
any variable?
Thanks, Sam”

Great question.  Let me begin by explaining what Eco mode is, and then what “Boost” is so we all have a frame of reference.

Eco mode is one of the two modes offerered on every Optibike, the other mode is FAST mode.  Eco mode is a reduced power mode that delivers about half power so you can ride you Optibike for twice as long.  To be more specific, on an Optibike 800Li the runtime is about 50 minutes in fast mode and is 2 hours and 15 minutes in eco mode.

Boost is a reference to the patented Derivative Power Control (DPC) that is (partially) responsible for the unmatched efficiency and acceleration of the Optibike.  Essentially, whenever you shift the Optibike or first accelerate from a stop, you feel the “boost” kick in.  The “boost” is an approximately several second burst of power that accelerates you “through” the gear you are in- up to a cruising speed, very quickly.  Once you are at cruising speed, you do not need as much power to keep you there- so the boost backs off.

The duration of the boost changes in accordance with a proprietary computer alogrithim developed by Optibike.  In other words, I could tell you but I would have to kill you. 🙂

Tricking the boost is what Sam was referring to when he was rapidly shifting going up hill.  If you feather the throttle or shift up and down rapidly, the Optibike will be very fast because it will never leave boost mode.  This causes the battery to drain much faster than normal (because of the increased power drain), and will eventually result in the Motorized Bottom Brackett (MBB) to begin “missing” which is an overheat default function meant to help cool the MBB to prevent permanent damage.  While this is a fun way to ride because the bike is VERY fast- your range is much shorter and overheating may result- leaving you waiting a few minutes for things to cool off.

My suggestion: When riding on terrain (or in circumstances) where you need more power- going uphill, start and stop traffic, blasting past roadies in spandex, etc; ride your Optibike in FAST mode.  This will keep you from constantly tapping into the boost feature and will extend your total ride time.  Of course, if you want to keep boosting- please do.  🙂

Jim Turner is the Inventor and Founder of Optibike Electric Bikes


  • opti says:

    Of course you can! Every Optibike comes with a variable rate throttle so you are in control at all times- and you have the power to get you up even the toughest hills.

    Craig Taber

  • lynda says:

    Another question. I am 67, female and haven’t ridden a bike for 10 years (and then only on side streets) because of extreme hills in our neighborhood. I’m concerned about keeping the speed DOWN and maintaining control. Can I keep the speed slow and still pedal but with some help?

  • Sam says:

    Thanks for the great answer, Craig.

    When I ‘trick the boost’, I only shift up until I get to top gear, full effort. I don’t downshift. This keeps the boost phase going right up to top gear, gathering enough speed & momentum until the top of the hill and the beginning of the descent when you don’t need any boost. If you downshift, you loose speed immediately.

    Of course, without downshifting, this only works on moderate grades.


  • opti says:


    Great question, but I can’t tell you. We have to keep some things secret. We have no plans for a variable boost feature on current models.


  • Dan R. says:


    Nice blog. Further questions, How is the magnitude and rate of the boost determined? Are you going to make that boost rate selectable via a software upgrade?