EM3ev MAC motor for fat bikes !!

S

saucisse

10 mW
Joined
May 11, 2014
Messages
30
Location
Quebec City, Canada
First off, I don't know if this was posted before but I don't think it was by Paul's comments. Paul is now carrying custom made MAC motors for fat bikes with dropouts ranging from 170-185mm.

A little background on this finding... I was looking for a stealth and light install for my Norco Bigfoot 6.2 fat bike. So far, all local shops are only offering a front hub conversion which is a no go for me.

As stated in another post, I'm not looking for a speed monster, only for some assist for the snowy steep trails we have in my area. I was about to pull the trigger on the mid-drivre BBS02 with the 100mm bb conversion kit offered by california ebikes but being in Canada, when looking at the CAD vs USD exchange rate lately plus cost of shipping, import/custom/taxe fees, final price is over $1800 CAD which is more than the price I've paid for the bike itself...



Below is a summary of the emails I've got from him, of course I've ask him first if this was ok to post here:

Ok, you can mention what I told you, no problem and show the pic.

The shaft is 175mm, as in 175mm dropout. It’s really quite simple, the shaft is longer than standard(which includes a bearing), to maintain the correct disc to dropout spacing In addition to this, there is more space on the freewheel side than normal, so you can fit a 10sp freewheel without any problem. The motor is reasonably centered in the axle. The hub itself is unchanged.

I’ve asked for a drawing of the finished motor, but I don’t have it yet. I don’t expect there will be any major issues making it work in a fat bike frame with anywhere from 170-185mm dropout, or thereabouts.

To order this custom motor, here's what he told me:

Select a standard motor, they are only available in 10 and 12T (upgrade type) at this present time. We do not have any suitable fat rims so far. If you want to select the motor here and checkout with request a quote, add comments about your special requirements, I’ll respond with a revised invoice:


Thanks
Click to expand...

In the coming weeks I'll order this motor / drive combo with CA V3 and I'll be reporting here.
 

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Great news! Thanks for the post. I'm the happy owner of a MAC 10T. Regarding the wheel: Paul does offer the Alexrims DX32, the most robust of that make. I put a 2.5" Maxxis Hookworm on it. But no reason you could not put a 3" tire on it. 3" is getting into too fat for the standard MTB and fat enough for a fat-bike. Reason being, Paul does great work threading his motors into rims, complete with high quality Sapim spokes.
 
May I ask how many spoke holes the motor has?

Simonism
 
Subscribed!

Please keep us updated on the build. I have an old 170mm fatbike that I've been looking to upgrade.
 
saucisse said:
Its got 36!

Simonism said:
May I ask how many spoke holes the motor has?

Simonism
Click to expand...
Click to expand...

Thanks saucisse!

Hi, if you're the same saucisse as is into FPV on RCG!

Simon
 
I have been told that the cheap Walmart single-speed Beast has a 190mm rear drop-outs, 7-speed Dolomite has 205mm, but the majority of other fat frames should accept the 175mm axle-shoulder MAC quite well. I have emailed fat-bikes.com for their secret stache of info on fat drop-out widths, and will post them as soon as I have new info.
 
Just got in the new FatMAC, it looks awesome check it out

https://electricfatbike.wordpress.com/2015/02/11/the-new-fat-mac-motor-has-arrived-at-long-last/

Ride On.

Karl
 
That is great news Karl!

Can you measure the overall length of the shaft?

Also, on which wheel are you going to lace this motor on?

Cheers!



gridlok said:
Just got in the new FatMAC, it looks awesome check it out

https://electricfatbike.wordpress.com/2015/02/11/the-new-fat-mac-motor-has-arrived-at-long-last/

Ride On.

Karl
Click to expand...
 
36 spoke holes huh?

Most fatbike rims that I have seen are 32H

Any one have links to good 36H fat bike rims?
 
If you have a 3-3.25" tire, i'd imagine that a 32mm wide rim would be great.

I have 24mm rims here and 2.5" hookworms fit on it just perfect. Whereas, 2 inch tires tend to have a bit of an eraser-head stretched out look to them.

v7cn7c.jpg


Here's a 33mm internal wide rim with a 3 inch tire on it.
 
gridlok, could you please measure the total width of the FatMac axle, both with and without the wire notch? I saw your pics, and you were right there measuring things already (argh).. You said it would easily fit the (very wide... widest, AFAIK) 205mm rear dropout of the Dolomite, but didn't give the exact width. Sorry, chomping at the bit, ha ha. That's great that you got it, thank you for the pics and info!!

I just realized that every FatBike BD sells, is 32-spoke. Argh. (MAC is 36, as normal.) I'm glad I didn't buy anything before realizing this.

It's great that EM3EV has these, but now with the spoke thing, I feel as soon as I surmount some major thing for a fatbike project, another thing pops up.

The last thing I've wanted to do was buy a freaking frame/fork combo and build it up (don't have the skills, tools, or really time)--especially the spoke stuff--but it's starting to look like if I want a fat ebike for mid to lower price, I might have to do this (sigh). I had basically given up until I learned about EM3EV's development. Still not sure it's worth it. I'd rather be riding than doing months of research and becoming a bicycle expert just to have 1 bike, but 1 bike the way I want it.
 
Also, I'm seeing bikes with rear Thru-axle frames. I assume a MAC or any drop-in hub motor would not work in thru-axles? Am I right?

Such as on:
http://www.bikesdirect.com/products/motobecane/fat-bikes/fat-bikes-bluto-frame-fatbikes.htm
Hi-res:
http://www.bikesdirect.com/products/motobecane/fat-bikes/bulletframe-slvr-21.jpg

BTW this is a perfect example of something in front of me at every step of the way on this. It's starting to seem cosmic. <whine mode off>
 
SprocketLocket said:
Still not sure it's worth it. I'd rather be riding than doing months of research and becoming a bicycle expert just to have 1 bike, but 1 bike the way I want it.
Click to expand...

That's the reality of trying to build something different than the norm. If you want a good E Fatbike, you have to work for it.

As for the 36 hole rims, I used some from choppersus.com. They're double wall, which IMHO is more appropriate for the power and speed of an ebike. You can drill them to save some weight, but at the pressures a Fatbike tire needs on the street at speed, large drilled holes are a liability.
 
After joining here, I spent 4 months reading before i built anything. The forums were even more disorganized than they are now. There's just a lot of choices out there.

And no, a flat shaft axle will not work in a thru-axle dropout without some modification of the frame or fabrication otherwise. You could perhaps use very thick torque arms bolted to the frame to adapt it though..

but i would go buy a cheap fatbike frame that already has the appropriate dropouts instead.
 
https://electricfatbike.wordpress.com/2015/02/11/the-new-fat-mac-motor-has-arrived-at-long-last/

They say. " The spacing is insane on this motor. It will easily fit a 205mm dropout with a few washers. The rotor mount is pretty far in from the dropout and on some installs you will need to install a rotor spacer and possibly space the caliper out towards the tire as well."

Nice, sounds like it will bolt right on to any fat bike out there pretty much, as long as it has a 10mm dropout. Plenty of axle stub it appears.

Dual Mac 12t's would make a hell of a nice bike for cruising deep sand beaches.
 
Question: So it's basically not possible to use the existing (36) holes in the MAC hub, and lace in a 32-hole rim, and just leave some MAC hub spoke holes unused? Like cal3thousand pointed out, almost every fatbike, and certainly all the 'affordable' ones I've seen, have been 32-hole. I can find aftermarket 36H bare rims, but at their price, it's worth me asking the group if it's possible to do the above kluge?

Oh: and Every BD fatbike uses Weinmann rims: 50mm for the cheaper models, 80mm for the higher end. From the pics, these have holes. I assume they're single-walled, but don't know.

Drunkunk, your comment about having to work for it, the truth of it struck me funny for some reason, and got a vocal LOL from me. You're right. I've seen that ChoppersRus page, but didn't realize they were double-walled; thanks.

I also came across this comment at fat-bike.com: "Niagra Cycles sells Weinmann rims in 65, 80, and 100 widths, 36 or 32 hole. Very similar to the ChoppersUS rims. They are double wall, heavy but can be drilled. No bead Lock but very reasonably priced." Even after some research, I'm not sure what a bead lock is, to show you what a noob I still am, but 65mm seems very interesting as a nice compromise.
Source: http://fat-bike.com/2013/04/fat-bike-101-rims/

And Nepi, I pretty much consider you a genius with this stuff, and I'm sure very intelligent with many other things, so it made me feel good to know I wasn't alone in researching for months before building anything.

And DogMan, thank you for the reassurance as well.
 
Has anybody actually installed the Fat MAC on a bike with 190 mm dropouts?

The Mongoose Hitch I have has 190mm dropouts and I am a little concerned about being able to get the brake rotor and rear sprocket spaced properly as well as having enough axle to bolt the motor on securely. The axle nuts that come with the MAC are fairly wide :wink: .

Yep I know this is an old thread...just got a used Mongoose Hitch and would like to try a 12T MAC on it and run a Maxxis 26x4.8" tire at about 10 psi. My objective is to use the rear tire as a pseudo rear suspension and install a SR Suntour Raidon fork with a 27.5" rim/tire on the front. A 27.5x2.8" DHF has been working pretty good on the front of my other Hitch both off road and on pavement...it has a BBSHD.

Thanks for any related info :D .
 
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