To gear sensor or not to gear sensor - that is the question.
I have ordered one of the new gear sensors from Luna and have been thinking about it. Here are my thoughts:
With the announcement of gear sensor availability from Luna Cycle we now have options to consider to protect our drive train while shifting. Instead of figuring out how to shift safely under power by finding ways to manually cut the motor, we can add a shift sensor and let it and the BBSxx automatically handle it for us. We are now a step closer to those high-end factory ebikes that are so smooth but unlike our Bafang solutions are under-powered and over-hyped. They do still have one leg up on us though and that is PAS with torque sensing. That takes PAS to a whole new level but is a topic for a future date (are you listening Bafang?).
If you don't use PAS, you don't need the gear sensor unless you don't want to let off the throttle while shifting gears. To shift safely using the throttle just let off the throttle and shift. If you can't coordinate that then by all means get the gear sensor and it will lay off the throttle for you. Granted there are times riding single track that is hard to lay off the throttle because of the grip you have on the bars. So mountain bikers that are using throttle only could definitely use a gear sensor.
If you use PAS and pride yourself in saving $50 by learning manual shift techniques like lightly squeezing the brake or back pedaling to cut the motor before shifting, you may not be a candidate for the new shift sensor. If you ever bought a car with a manual transmission for the pure joy of fussing with the controls, pressing in the clutch and moving the shift lever, you may also not be a candidate. Although you will not be doing something natural like pushing a clutch, you will be unnaturally pulling the brake or back pedalling to shift which may not bring the same pure joy.
However, if you use PAS and like me don't like to do something unnatural like squeeze the brake or backpedal to shift and despite your best attempts to master these techniques find you occasionally shift before the motor cuts out and you hear and feel a hard 750W+ clunk go through your drive train then you are definitely a candidate for the gear sensor. The ability to shift gears just like you always have without worrying about what the motor is doing with the PAS system or whether you can even let off the throttle (think gripping the bars on a hill riding single track) has got to be nice.
If you use PAS without a gear sensor there is an often glossed over controller programming parameter under "Pedal Assist" called "Time of stop" that can make a huge difference. The "Time of stop" value is multiplied by 10 to get the number of milliseconds after you stop pedaling until the motor stops. Most vendors are setting this to a value of 25 which introduces a full quarter second delay (250ms) between the time you stop pedaling and when the motor actually quits. This is why people use brakes and back pedaling to ensure that power to the motor is cut before shifting. If you set it to 5 (don't set it any lower or PAS will stop working) then it only waits 1/20th of a second (50ms) before cutting the motor so you can just stop pedaling and then shift and the timing works out. Karl Gesslein, in his "Hackers Guide to Programming the BBS02 and BBSHD" makes the statement, "I strongly recommend setting this to 5, especially if you want to use the PAS system without using ebrakes." Curiously, out of 5 vendors and experts with recommendations, all of them but Karl recommend a value of 25. Trust me, changing this to 5 makes a HUGE difference. Unfortunately, a side effect of this setting is that at slow cadences the pulses from the PAS magnetic poles are coming slow enough that there is a greater than 50ms delay between pulses and the motor never engages. If this happens, you are probably in too high of a gear anyway. The solution of course is to shift to a low enough gear that your cadence is high enough that it doesn't time out between PAS pulses. You can play with optimizing this for your own style by playing with numbers between 5 and 25 but it will be a compromise. Alternatively, you can just get the new gear sensor from Luna and not worry about it. That's what I am doing. :)
With the announcement of gear sensor availability from Luna Cycle we now have options to consider to protect our drive train while shifting. Instead of figuring out how to shift safely under power by finding ways to manually cut the motor, we can add a shift sensor and let it and the BBSxx automatically handle it for us. We are now a step closer to those high-end factory ebikes that are so smooth but unlike our Bafang solutions are under-powered and over-hyped. They do still have one leg up on us though and that is PAS with torque sensing. That takes PAS to a whole new level but is a topic for a future date (are you listening Bafang?).
If you don't use PAS, you don't need the gear sensor unless you don't want to let off the throttle while shifting gears. To shift safely using the throttle just let off the throttle and shift. If you can't coordinate that then by all means get the gear sensor and it will lay off the throttle for you. Granted there are times riding single track that is hard to lay off the throttle because of the grip you have on the bars. So mountain bikers that are using throttle only could definitely use a gear sensor.
If you use PAS and pride yourself in saving $50 by learning manual shift techniques like lightly squeezing the brake or back pedaling to cut the motor before shifting, you may not be a candidate for the new shift sensor. If you ever bought a car with a manual transmission for the pure joy of fussing with the controls, pressing in the clutch and moving the shift lever, you may also not be a candidate. Although you will not be doing something natural like pushing a clutch, you will be unnaturally pulling the brake or back pedalling to shift which may not bring the same pure joy.
However, if you use PAS and like me don't like to do something unnatural like squeeze the brake or backpedal to shift and despite your best attempts to master these techniques find you occasionally shift before the motor cuts out and you hear and feel a hard 750W+ clunk go through your drive train then you are definitely a candidate for the gear sensor. The ability to shift gears just like you always have without worrying about what the motor is doing with the PAS system or whether you can even let off the throttle (think gripping the bars on a hill riding single track) has got to be nice.
If you use PAS without a gear sensor there is an often glossed over controller programming parameter under "Pedal Assist" called "Time of stop" that can make a huge difference. The "Time of stop" value is multiplied by 10 to get the number of milliseconds after you stop pedaling until the motor stops. Most vendors are setting this to a value of 25 which introduces a full quarter second delay (250ms) between the time you stop pedaling and when the motor actually quits. This is why people use brakes and back pedaling to ensure that power to the motor is cut before shifting. If you set it to 5 (don't set it any lower or PAS will stop working) then it only waits 1/20th of a second (50ms) before cutting the motor so you can just stop pedaling and then shift and the timing works out. Karl Gesslein, in his "Hackers Guide to Programming the BBS02 and BBSHD" makes the statement, "I strongly recommend setting this to 5, especially if you want to use the PAS system without using ebrakes." Curiously, out of 5 vendors and experts with recommendations, all of them but Karl recommend a value of 25. Trust me, changing this to 5 makes a HUGE difference. Unfortunately, a side effect of this setting is that at slow cadences the pulses from the PAS magnetic poles are coming slow enough that there is a greater than 50ms delay between pulses and the motor never engages. If this happens, you are probably in too high of a gear anyway. The solution of course is to shift to a low enough gear that your cadence is high enough that it doesn't time out between PAS pulses. You can play with optimizing this for your own style by playing with numbers between 5 and 25 but it will be a compromise. Alternatively, you can just get the new gear sensor from Luna and not worry about it. That's what I am doing. :)
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