How Important Is Electronic Gear Change Sensing (shift sensor)?

[Douglas Wever]

Buying my first bike, and in the reviews some bikes have sensors that reduce power during a gear change to reduce shock and stress to the driveline. Others do not.

How important is this?
And where in the review specifications can I see if a given model has this feature?
What is it called?

Thanks!

 

[flymeaway]

How important is this?

On a mid-drive configuration, stopping the motor prior to shifting is important. On a hub motor not needed.

Court J.

 

[pxpaulx]

Depends on the mid drive too. I've got the Yamaha haibike and have zero issue without the gear sensing tech. Since the pedal sensor is torque based, a split second (I'd say literally less than 1/8 off a crank turn at 70rpm) ease off the pedals is all it takes to avoid crunching the gears

 

[Adrian]

I crunched my gears like crazy at first which helped to destroy a chain. Now I rarely do - it's a matter of practice. Gear sensor is a nice to have but now, it's not worth the hassle to install - I may get one one day when I have some spare time to work on the bike.

 

[flymeaway]

Depends on the mid drive too.

If you have the programming cable for the Bafang BBS drive you can program the stop delay time in milliseconds. I have programmed my drives with zero stop delay so the motor stops as soon as I stop pedaling. I use to use the "clutch" method which worked, but reprogramming the controller makes the process more streamline. The only drawback is having the delay between stopping and starting. You can start the motor at full output with a zero start ramp but that would invite frying the controller, so a ramp start is a necessity.

Court J.

 

[Jack Tyler]

Don't overlook the importance of the motor's wattage. I found the E3 ProTour 500W motor, which lacks shift sensing, to make gear changing very difficult to accomplish without gnashing...and that was with very deliberate release of crank pressure when shifting gears. I could feather in the gear changes nicely some of the time but not routinely...and when I was unsuccessful, the sound & strain were anxiety-producing! OTOH I found no need for shift sensing when shifting a Bulls mid-drive that used a Brose 250W motor; it actually performed a bit better for me than a Performance Bosch motor/drive set on a Haibike *with* shift sensing. I'm afraid this is another example of why test riding before buying makes a lot of sense.

 

[Douglas Wever]

I'm the OP, great responses for a total newbie, thank you. I was able to get a new but close-out 2015 Raleigh Detour iE today for $1,699, so I thought that would be a good starter, I'll ride for a few months and then see if I want to step up to a Class 3. My last bike was a Trek 721 touring rig.

Put on 22 miles in three rides between 10a and 1P in significant heat and I'm not sweating profusely. Good grief. So for shifting I'm just lightening up the crank pressure so it feathers in there. No problems, probably will take a couple weeks to do it consistently. MOTOR NOMINAL OUTPUT: 500 watts, 48 volts BATTERY AMP HOURS: 8.8 ah 422.4. Great so far.

 

[TrevorB]

I've had no problems on Shimano mid drive, just ease of while changing. After while it becomes automatic. Changes are slower than on my manual bike but then again I don't need to change as often on ebike, quite often switch power assist level as an alternative.

 

[Carl_L]

Think it's very much dependent on how much of a 'power' rider you are. In other words, whether you have very strong legs and/or you use the bike more on maximum assist rather than, as I do, err for the lower power modes for increased range.

Either way, it's not a must have - chains & cassettes aren't that expensive. Probably more important to buy a chain-checking tool so you at least know when your chain is worn - busting a chain on a ride spoils your day.

When comparing feel on test rides, make sure you're aware of the different characteristics of rear mechs beforehand. Shimano Shadow Plus derailleurs have a clutch to keep the chain tensioned - this gives a very noticeable THUNK when changing up - do not confuse this with a problem with either a lack of, or inadequate, shift detection.

Edit - Oops! Just realised you'd subsequently posted that you've now purchased a new (hub drive) bike. So, for you, the question is now a moot point.

Have fun with your new bike

 

[harryS]

Interesting that no one has asserted so far that a shift sensor is necessary. Perhaps it's needed for certain trail riding techniques. In my three weeks of BBS02 riding on the street, I have found that I don't need one at low PAS levels, and pausing at higher PAS levels will suffice..

I have found that I get chain clash if I shift with the the throttle open, but that goes against years of driving stock shift cars and riding motorcyles, where we always close the throttle on shifts, ignoring what the the Beach Boys sang in "Shut Down".

 

[eoghan]

I turned it off on my Xduro

 

[Ann M.]

Congrats on the new Raleigh, @Douglas Wever ! Nice pic; looking forward to your thoughts and pics as you pack on the miles.