Front motors get a lot of bad publicity, but they can be quite good if you manage your expectations. PromptCritical since you are planning on low power, you won't be experiencing any handling issues of any kind. Also, you have already been pointed to Grin Technologies. Look to their V5 torque arm. Its a $20 insurance policy you should use REGARDLESS of whether you install to an alloy or chromoly fork. Steel fork dropouts can still be damaged by a front motor. Instead of breaking like they typically do on an alloy fork, they spread so they are no longer parallel, and once the metal has fatigued like that it will forever do so relatively easily, so the fork is effectively destroyed. I learned this the hard way back in I think 2015 on my first awd ebike build.

Never under any circumstances put a front motor on a bike with a suspension fork. There are actually some circumstances where it can be done safely, and your low power scenario is one of them, but I would not recommend to a beginner builder to try this. If you do some looking around you will find that the alloy dropouts on suspension forks are infamous for snapping clean off. Plus no fork is designed to be pulled on, and you can watch a suspension fork try to pull itself apart under powered acceleration. Here again your low power no throttle config would be likely safe, but I still would never recommend a beginner take on this level of risk.

You'll hear a lot of talk about how front motors have traction issues versus a rear motor, which is the wheel that is carrying all the weight. In reality, on a mild-duty street bike, this is a complete non-issue. It will pull just fine and in fact a powered front wheel with your legs powering the back wheel creates a mild awd bike, and the benefits of distributed traction are really a bit of a beautiful thing, but you'll find plenty of keyboard riders who pooh-pooh the concept. If you are looking for a light-duty assist on a bike you primarily pedal and don't expect to throttle you around, a front wheel on a solid steel fork is hard to beat. Especially for your first project.

But... Do a torque arm no matter what. I have lived the dream of destroying a fork and for under thirty bucks for a quality product consider it cheap insurance (read Grin Tech's torque arm info page and stay far, far away from the Chinesium clones of their v1.0 design that you can find all over Amazon and Ebay).

I would suggest a 48v system and a geared hub motor. In particular, a Bafang G020 which is a 45 Nm geared hub motor. Put a KT controller on it and set C5=00 on the controller for its mildest slow-start setting. You will have a very tame motor that will effectively last forever. A 48v system is one that, with a low power controller (say a KT brand 15a which would be very mild) that motor would sip power so gently almost any battery you use will effectively give you all the range you could ever ask for. A 48v system on PAS level 1 will output about 50w so you'll likely never see Level 5 which is going to be pumping out an entirely theoretical 800w as a peak. KT controllers also do not give you cadence sensing pedal assist that is the hated on/off switch that runs away from you.

The hub motor setup would be lowest-cost and easiest to install. More difficult but also more capable would be a BBS02. I am a huge fan of mid drives, and have written build guides designed specifically to get the beginner past most of the dumb mistakes that builders make that give mids a bad rep insofar as reliability and increased wear and tear are concerned. However, hub motors have their place and for beginning builders and mild duty cycles (flat land and no steep hills!) they can be a fine choice.

This and a separate article on the same site about riding technique cover the potential pitfalls. It is aimed more squarely at the BBSHD, but everything applies the same for a BBS02. The consequences are just less severe.

How to Build a Mid Drive Ebike That Doesn't Break

My next article coming out in the not so distant future is going to be entitled something along the lines of 'how to add a hub motor to your bike all by yourself' or something like that. I've pretty much beaten to death the mid drive subject.