I've thought about doing the same thing, deciding which torque sensor to use has kept me from doing it as of yet...
If you already have your new system running, which torque sensor did you buy and how would you compare the behavior and performance of the system to your Bionx?
Happy to help Scott,
On my new builds (2 so far) I have gone with products from
www.ebikes.ca (Grin Technologies).
The motors are 9C 212 series Hub Motors...in both builds I happen to decide to go with 2WD. Road bike for the summer, Fat bike for dirt/winter. All motors are connected to PhaseRunner Controllers.
Connected to the PhaseRunners is Grin's famous Bike computer? (not sure what to call it exactly, lol) Cycle Analyst 3 (CA3 for short).
I did try (for testing and experience) a PAS sensor for $30 and to have as a 'quick fix' backup if ever needed. Good experience, taught me I realllllly like Torque sensors.
Finally, here are the various torque sensors Grin sells:
Options to add automatic pedal assistance to engage the motor on your bike.
www.ebikes.ca
and here is a nice write up about the different manufacturers of torque sensors Grin offers:
Most ebikes these days offer some form of automated pedal control (PAS = Pedal Assist System), where the motor is powered in response to you pedaling the cranks and not just from a throttle on the handlebar. Here we summarize both the Cadence based and Torque based PAS sensors available for all...
www.ebikes.ca
The exact model I have installed now is this ERider unit:
ERider-T9N Torque Sensor for 68mm BB Shells with 170mm Miranda Cranks and 4 Bolt 104mm BCD Chainring Spider. Side Cable Exit. Chainrings Not Included. NOTE: Certain ERider setups are succeptible to electrical noise from the controller causing intermittent cutout behavior. This can be solved by...
www.ebikes.ca
Notes from using it thus far:
-Install was so easy. No drilling a cable exit hole (part of why I chose it) as the cable exits the left side and runs up to the CA3 on the handle bars. I bought the proper BB tools for $30 from Amazon and swapped the BB myself at home.
-The 165mm cranks it comes with are great. If you want to change the cranks (length, type, etc) you simply need to purchase a model with the 'square hole' type connection.
-Bonus: In my case this setup works perfect with my 2WD setup which is a relief as I didn't know until I had it installed how well it would work.
Experience:
-The superman feeling when you press down on the pedals mid-ride is exactly the same as my Bionx.
-The only slight difference is the engagement of the motors compared to Bionx - Bionx is basically 'instant' - The BB model takes about a 1/2 to 1 full revolution of the cranks on my current setup. There is settings I will dial down (CA3 is amazing for customizing) but the manual warns setting it too low can cause other issues such as a chatter-like throttle response. As it is now I'm super happy.
-As my road going bike is rather heavy (around 200lbs before rider) I simply use the thumb throttle when I launch each time, it's automatic in my experience already and unique to my first main bike being so heavy.
Bonus - with this setup the CA3 displays (and if you get the optional data recorder, records and keeps) your Human Watts input to the pedals. This saved me spending $300 to ???? dollars on a set of non-e style watt meter pedals to gain this information. I average between 150-180 watts of input is what I have learned and look forward to seeing my improvement over the years to come.
If budget is an issue, I believe these torque sensors are compatible with connecting directly to the controller of your choice - plug and play if it's a controller from Grin, wiring diagram if needed for others.
To also share, I have the programming software for my Bionx bikes. It allowed me to change the 25/50/100/200 boost settings to other levels that helped me have more of a fine tuned riding experience for each bike and my riding type/weight/etc.
The CA3 takes this experience to a whole other level of customization. With the digital input by my thumb I simply selected the 9 level of PAS option. It took my maximum boost factor (currently set to 8X human watts, silly, I know, lol) and now I have 0,1,2,3,4,5,6,7, and 8X at the touch of my thumb. I riding mostly in 2-4X (270lb rider, 200lb bike) and just like the Bionx 'level 4' I can dial all the way up to 8X for the steepest of hill climbs...
...with 2 x 1500watts of motor pulling my fat butt all the way up and never breaking 45C in temperatures.
I will follow up with my experience of my fat bike using the same motors/controllers/CA3 and a different BB model (SEMPU-175 for the 100mm bottom bracket the bike has) when it's complete and I have a few rides on it.
Have a look at the links I included here and if you have any questions feel free to quote my reply here (so I see the alert when I log in next, like I did today) or PM me any questions you may have.
Cheers
Shaun