Johnson monster motor
 

it'll work okay. do it up if that's what you desire. 15/66 is a good starting point. of course a motor without brushes would be better.

I would suggest getting a pinion puller to remove the pressed on pinion, then file a flat spot on the shaft so you can use normal pinions.

If you are going to use it as a single motor on its own in the maxx, I'd say gear it pretty much the same as you would a pair of titans that it replaces, something like 18/72 to start with, then work down on the spur or up on the pinion until you are happy or the motor starts to run too hot (outside of its most efficient gearing range).

kershaw designs will have a motor plate for you

Why not use a smaller spur and 22t pinion. 66t is stock on the 3906, 68t on the 3905. Notice the operating voltage of that motor, your EVX won't power it at its most efficient RPM(18v). I wouldn't use it personally, my bet is it will be slower than stock.

My question is why? 970 motors are pretty much junk in RC applications. Too big, too heavy, too much battery power required. They add a metric ton and require too much work stiffening and upgrading stuff that can't handle the weight.

A mm should hadle the 970 fine if you are doing 14cells nimh or 4s lipo max. If you are going higher then the MMM is the best bet. Price will be about the same once you add a ubec to the MM so the MMM is most likely the way to go. Or a novak super duty brushed esc, but the MMM will be more versatile and has computer programability. Hard to fine a better esc that the CC ones, they are very versatile and the price is almost too good to be true...

3906
 

Yea I am rebuilding a 3906 RCM monster myself and using two Dewalt 970 motors as well. I have the Kershaw Designs motor mounting plate and I am using the Novak Super Duty XR ESC. I am also using the RCM hybrid bulks with the HPI Lightning hardened diff gear setup. From what I can tell it will all work out just fine for what I want. I have plenty of gearing options due to the stocks that I have built up along the way. Sure it will be a little bit top heavy due to the setup, but it is a basher so who cares. I am planning to mount the battery packs below the chassis in order to compensate for these heavy motors being so high up. Hopefully this will counter act things a bit and lower the center of gravity for the setup. You have the motor already in hand so set it up and have some fun. There are a few guys on here who have already done this project with either Johnson or Dewalt motors and they seemed to have done ok and have had some fun with the project. So enjoy.:party: