Geared hub motors: BMC vs MAC Shanghai

I noticed that the BMC motor has holes on the cover between stator and gears. .Does anything think drilling similar holes
in the MAC would be beneficial for cooling ? Running my mac near the limits I am trying to figure out some way other then
filling it with oil to help keep it cooler or reduce cooling times between runs.
 
ohzee said:
I noticed that the BMC motor has holes on the cover between stator and gears. .Does anything think drilling similar holes
in the MAC would be beneficial for cooling ? Running my mac near the limits I am trying to figure out some way other then
filling it with oil to help keep it cooler or reduce cooling times between runs.
Click to expand...

The new magnet assembly in the MACs has these holes.
It might help, but it also opens up the possibility of getting grease on the stator.
You also end up shedding stator heat towards the gears.

I don't know if it's really beneficial at all. The benefit might be more in shedding weight from the motor.
 
Good point that the heat will go the wrong way. I just liked how BMC had the holes there.

Leaves me with drilling holes in the covers then. Mine is a mid kit so at least it's a bit safer from road debris.
 
All this talk makes me itch for the new 7T that's (hopefully) on the way soon from cellman
 
Prepare to have to do regular oil changes if you do that :(.. the grease inside will get dirty over time due to dust and other stuff in the air.

cell_man seems to be working on producing a larger MAC motor soon, FYI.
 
Any truth to the BMC being better in the rain. Is the Mac that bad? I live in the PNW but I have covered parking at work and at home. Still, sometimes it will be raining on the way. I was thinking about buying a MAC..
 
Has anybody been able to compare the noise levels between a BMC and a MAC?? Are they much noisier than direct Drive hubs?
 
My Mac hubs are quieter than my 9c hubs. There is a slight 'whine' with the Macs, but it's less noticable than the DD noise - which is still very quiet. They are worlds quieter than that gear reduction Currie motor I used years ago :D
 
How does the clutch work on these motors? Is it possible to have reverse with these motors? I would love to use them on a quad I am building. Does anyone know torque numbers?
 
This motor can't reverse due to the clutch, as you mentioned. The clutch uses ramped rollers...they work fine in oil if desired, plus the clutch can take a lot of heat. Sometimes these clutches have locked up from too much torque, but those guys were using temporary peaks of 3,000W. Awesome design for 1500W...maybe 2000W if you don't get them hot.

Once cell_man upgraded the laminations to the thinner ones, they are practically identical to the BMC. This is the best possible front motor for a 2WD...(IMHO)

https://endless-sphere.com/forums/viewtopic.php?f=16&t=51310
 
Technicaly, they are called Ramp and Roller or Sprag clutches.
 
i can say at least for the new 2016 version of the mac hub motor (cassette freewheel) with 12T windings. it does same to take my 60v setup pretty well, up to 2000w - i did not manage yet to break anything of the motor. sure, the 12t is not the best choice for such high voltage/power settings, temperature rises pretty quick above 90° C during city traffic (traffic light sprints :mrgreen: ) but the torque/acceleration is impressive amazing in this configuration. if you dont take care it might go for a wheelie and drop you off.

riding this for about 2000km ...
 
you mean if it fit well in the 135mm rear? pretty well, but with the shimano 11 speed cassette (m8000) which is about ~1.2mm more width than 10 speed you need to rip out on of the cogs, otherwise the lock ring wont fit anymore. the rear itself is definitly below 140mm, something like 137-138mm which was no problem. no abusive bending needed.

i got the 10t version right next to me, if you need any dimensions let me know
 
Is it common for the older BMC's to have the steel ring slip inside the alum cover plate?

I tried to get the cassette off a a year or so ago, I still have not fixed mine yet.
The last few days I thought about brazing it, a quick look cant find no alumi-steel brazing rod, they got al-steel welding rod though, I got no welder :( I could rent a welder for $10/hr, but I have never welded before. I could probably find a friend of a friend of a friend who is a welder. ebikes, sff, em3ev have plates but dunno if they would fit, plus they are expensive.

I may try to drill dowel holes between the two metals, then use steel epoxy.

I just thought of something, drilling steel bolts into the alum cover, then brazing steel.
 

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The only way to fix that woyuld be to have a pro MIG/TIG weld it, but I don't think it would be as strong as new.
Paul @ EM3ev has Mac replacement side covers for $15 that might work(from the pics here, it looks like it would). Email him and ask.
I have a new Ezee V1 side cov.
 
Yup I priced his out. $15usd + $50usd I think was the price for s/h. I may have to just buy one b/c the one I have is slightly cupped. If I needed other stuff from him I'd throw it into the cart bin as well but I dont. I know there is an easy fix, for a guy with the right tools. I will just ponder it some more and try to come up with some other idea's. I am liking the idea of threading in steel bolts into the alum cover but I dont know if my Home Depot propane torch would do a proper brazing steel. Most YT video's use Oxygen Acetylene torch. With that technique, there are various variations, thinking about it now as I type, I could use flat steel cut to fit, bolt it into the alum with proper bolts, then braze. So the holes would be further out from the inside hole edge.

Oh well I will leave it there, thanks for the help. I dont want to gunk up this thread any more.

I will try to find my old thread on this and move it to the top.
 
irq said:
i can say at least for the new 2016 version of the mac hub motor (cassette freewheel) with 12T windings. it does same to take my 60v setup pretty well, up to 2000w - i did not manage yet to break anything of the motor. sure, the 12t is not the best choice for such high voltage/power settings, temperature rises pretty quick above 90° C during city traffic (traffic light sprints :mrgreen: ) but the torque/acceleration is impressive amazing in this configuration. if you dont take care it might go for a wheelie and drop you off.

riding this for about 2000km ...
Click to expand...


Hey, What speeds are you getting on a flat no pedalling? Also are you using temp sensors and thermal rollback?
 
Good thread, but I hate when I don't pay attention and then realize it's 6 years old! And the first 3 posts are irrelevant. ARGH!
 
motomech said:
The only way to fix that woyuld be to have a pro MIG/TIG weld it, but I don't think it would be as strong as new.
Paul @ EM3ev has Mac replacement side covers for $15 that might work(from the pics here, it looks like it would). Email him and ask.
I have a new Ezee V1 side cov.
Click to expand...

His new website is good, but I did not see any cassette side cover plate, just disc side cover. Would like to get this motor going.
 
I just purchased my 1st geared rear hub motor. Its the BAFANG 750 WATT- 48 volt motor and I think this is the same motor used on the RAD ROVER.

Is this motor considered a good one ? It cost me $ 212 delivered and I laced it into a 26 inch fat bike rim . It has 3 white planetary nylon gears and I went ahead and put Automatic transmission fluid inside of it and attached aluminum heat sink cooling fins to the outside of the motor . My battery/controller combo allows me to pump around 2300 watts into this motor , and I'm hoping it will hold up . Heres a photo .

Also, does any company make metal gears to replace the nylon planetary gears in this motor >
 

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