Rear hub motor to Pinion bike?...

MusicCityEVs

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I've found several manufacturers selling bikes with Pinion gearboxes with a rear hub motor. Stromer has several models of bikes that have a Pinion gearbox with both belt drive and a rear hub motor as one example. So, it's been done by manufacturers but has anyone added a rear hub motor to a bike with a Pinion gearbox? That's my questions to all the bike builders out there.

I'm soon going to be the owner of one, possibly both, a front hub motor and/or a rear hub motor and am looking to electrify a non-electric donor bike with either an 18 speed or 12 speed Pinion gearbox. What are the necessary parts I need for this motor add-on? The two motors are the new version of Grin Technologies All-Axle motors and the front axle is doable if run with a throttle assist. I'm curious about trying to find out if I can use their new rear All-Axle motor with built-in torque sensing as I'm a big fan of torque sensing.

Thanks in advance.
 
Its a common modification. You can't do a mid drive for obvious reasons so the remaining best option is a big-ish direct drive hub motor, from what I have seen built out there.

Of course you could also do a front motor. If you try riding one, you'll typicall find its a lot nicer than the internet experts tell you it will be, because you wind up with a 2wd bike that has your legs powering the rear wheel, and ANY 2wd is going to be a big help even if the rear is your legs. You need to build it smarter though as overpowering the front wheel can make you giggle doing front wheel burnouts, but then the reality of a powered front wheel off the line with your handlebars turned sideways will eventually get you. And also the interwebs are littered with pics of snapped dropouts on suspension forks, with the lesson being NEVER EVER do a front hub motor with a suspension fork (the fix that manufacturers do that they don't talk about is they neuter the power on the front motor and use extra-heavy front fork dropouts).

A sane and powerful front motor includes dual torque arms, and you still don't overdo the power up front. 750w tops would be my advice. My 2wd Bullitt uses a 500w/45Nm motor with a 25a controller set to slow-start its acceleration.

On the back I have a BBSHD so yes its possible to do dual hub motors, but its a lot of work to make happen. Doing a 2wd bike RIGHT is a fair bit of work., I have been doing them for years, personally and have gone thru a few iterations.

What are the parts? Grin sells kits so buy everything they'll sell you. Particularly the torque arms. Use two on each wheel regardless of whether anyone says you just need one. You will need to be creative and on the back at least buy two different types.

I did a series on 2wd bikes you might find useful. The 2wd commuter uses dual hubs.


dual-motor bikes are a lot of work but the results are well worth the effort.
 
Its a common modification. You can't do a mid drive for obvious reasons so the remaining best option is a big-ish direct drive hub motor, from what I have seen built out there.

Of course you could also do a front motor. If you try riding one, you'll typicall find its a lot nicer than the internet experts tell you it will be, because you wind up with a 2wd bike that has your legs powering the rear wheel, and ANY 2wd is going to be a big help even if the rear is your legs. You need to build it smarter though as overpowering the front wheel can make you giggle doing front wheel burnouts, but then the reality of a powered front wheel off the line with your handlebars turned sideways will eventually get you. And also the interwebs are littered with pics of snapped dropouts on suspension forks, with the lesson being NEVER EVER do a front hub motor with a suspension fork (the fix that manufacturers do that they don't talk about is they neuter the power on the front motor and use extra-heavy front fork dropouts).

A sane and powerful front motor includes dual torque arms, and you still don't overdo the power up front. 750w tops would be my advice. My 2wd Bullitt uses a 500w/45Nm motor with a 25a controller set to slow-start its acceleration.

On the back I have a BBSHD so yes its possible to do dual hub motors, but its a lot of work to make happen. Doing a 2wd bike RIGHT is a fair bit of work., I have been doing them for years, personally and have gone thru a few iterations.

What are the parts? Grin sells kits so buy everything they'll sell you. Particularly the torque arms. Use two on each wheel regardless of whether anyone says you just need one. You will need to be creative and on the back at least buy two different types.

I did a series on 2wd bikes you might find useful. The 2wd commuter uses dual hubs.


dual-motor bikes are a lot of work but the results are well worth the effort.
Thanks for all the good tips and for sharing the link. I've watched many of the great videos that Justin and others have done through Grin and was set on using double torque arms already. I know that a front motor is doable, I understand about the various traction and braking issues with using front hub motors and am currently trying to figure out which parts are needed (freehub, pulleys, shims, etc) as I know several manufacturers have already released factory versions of rear hub motor bikes with Pinion gearboxes. I guess it's safe to say I'm currently focusing on skipping the AWD in favor of using Grin's Rear All-Axle with it's built-in torque sensing option because of the Pinion gearbox being in the way of the bottom bracket if I did run the front hub motor option. AWD was never a super high priority and was never the main reasoning for considering a front hub anyways. Eliminating 95+ % of brake wear was my number 1 reason for a hub motor anyway and Grin's front or rear All-Axle motors can accomplish that with their regenerative capabilities.

I'm fixing to call Pinion and/or Stromer and ask for advice on the necessary parts.

Please keep in mind that I'm also looking to use a belt drive.
 
You may find regen to be a disappointment. Not the least of the reasons is you will lose the ability to coast. The bike will either be under power or decelerating via regen. Also regen except in its most aggressive forms doesn't put much back into the battery system, so its value in practical terms is often a lot less than what was expected. Whether you use regen or not, awd or not, the All Axle is an excellent hub motor option. The CA3 is a bit of a challenge to deal with but once you dial in what you want done it will be fine.

No reason you shouldn't be able to use a belt drive so long as you hale the usual alignment issues and of course can deal with the frame break assuming a standard 1-pc belt.

Only reason I brought up awd is you mentioned it as a possibility. For a beginner builder thats not a level of complication I would recommend. However, a CA3 should be able to enable dual PAS to both motors. Its just going to have to be cadence based. If you were doing a KT controller you could use their simulated torque assist which is night/day different from what most people think of on cadence PAS but not a good choice for a Grin motor, assuming it is even possible.
 
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