# QS138 Motor version differences



## LarryM (Oct 21, 2021)

Does anyone understand the difference in those charts well enough to provide any insight on best choice?


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## EJFitz (Oct 24, 2021)

I also don't know a whole lot about motors, but I've been trying to learn a lot in the past week. You should check out BigGuyLittleBikes video on YouTube (



). It's a video about hub motors specifically, but he includes a spreadsheet that will likely be helpful for choosing any kind of motor. Another good idea would be to go to QS motors website (QSMotors.com) and send them a message saying what you're building and what you hope to get out of it. I've heard from others that they're very helpful and could get you on the right track. Best of luck!


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## Picassoster (Jun 22, 2021)

They are basically the same motor - with same performance. The V1 had some issue with the sproket attaching to the shaft thus they updated to the V2 that has a stonger design. The V2 also comes with different mounting brackets and option for a belt pulley.
The V3 is the same motor with an integrated 2.35:1 gearing reduction so it delivers more torque but lower rpm (same power) - It's used to avoid a dual chain transmission usually needed to reach 7:1 or higher ratio with standard sprokets. The downside is that it's larger so you need more space to fit in to the frame.


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## Jordan325ic (Jun 8, 2021)

The QS 138 is normally listed as a 3kw motor, but it is usually sold with a 10kW capable controller, and I have not heard of any issues running it at that power level (and much higher). So whether it is listed at 3kw or 6kw is arbitrary, the only differences are the V1,2and3 as explained above and maybe 70H or 90H.


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