Geared hub motor for cruiser tandem/

EMGX

Well-Known Member
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We've had this cruiser tandem for about 8 years, not ridden a lot but it was a lot of fun when we did. Our favorite paths to ride are hilly - I can put in a lot of effort but my wife has knee issues and isn't able to pedal hard anymore so it has sat unused for a couple years. I was going to get rid of the bike because it just takes up space but my wife asked me to keep it. In order to be useable on the paths we would like to ride we would need assist. I tried a 36v 250w MXUS geared front hub motor which didn't help except on flats or mild inclines where assist wasn't needed. A mid drive in the front bottom bracket wouldn't work because the chainline wouldn't be compatible. Anyone have experience with a Bafang 48v 750w rear geared hub motor? Serious assist for hills taken at slow speeds 8-10mph, or would it stall out? Another issue is that the rim brakes aren't great for this bike and I would have to look into using a disc brake adapter. Anyone use something like this with success?
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EMGX

Well-Known Member
Looking more closely it appears that the 48v 750w 80nm version is for fat tire bikes and wouldn't fit. Not sure that I would bother with a 500w version.
 

indianajo

Well-Known Member
I've been moving up to 330 lb gross up grades of up to 15% for 3 years, with a front geared hub motor. I was unable to find a bafang that was not for fat tires, so I bought an ebikeling.com 48 v 1300 W geared motor in wheel, with controller, display, PAS pickup, brake handles, for $221. It was quite capable of my load. It lasted ~4500 miles before a plastic gear wore out. I bought a 500 w MAC12 geared hub motor ($750) the year before the ebikeling wore out. It is also quite capable of the load on the worst grade, and uses less watthours over my 30 mile ~80 hill commute to my summer camp.
I had a 1000 W direct drive geared hub motor ($189) on the rear for a while, but didn't like coping with only 7 sprockets sizes on the rear, 14 to 28 instead of the 11 to 32 8 speed sprocket that came with my bike.
The DD motor could move weights, although I never tried it with the maximum load on the maximum grades out near my summer camp. It did use an awful lot of watt hours, much more than even the ebikeling geared hub motor. I ride ~ 8 mph typically, although I do roll hills at up to 30 mph on excellent pavement to maintain momentum from one hill to the next.
 

EMGX

Well-Known Member
I've been moving up to 330 lb gross up grades of up to 15% for 3 years, with a front geared hub motor. I was unable to find a bafang that was not for fat tires, so I bought an ebikeling.com 48 v 1300 W geared motor in wheel, with controller, display, PAS pickup, brake handles, for $221. It was quite capable of my load. It lasted ~4500 miles before a plastic gear wore out. I bought a 500 w MAC12 geared hub motor ($750) the year before the ebikeling wore out. It is also quite capable of the load on the worst grade, and uses less watthours over my 30 mile ~80 hill commute to my summer camp.
I had a 1000 W direct drive geared hub motor ($189) on the rear for a while, but didn't like coping with only 7 sprockets sizes on the rear, 14 to 28 instead of the 11 to 32 8 speed sprocket that came with my bike.
The DD motor could move weights, although I never tried it with the maximum load on the maximum grades out near my summer camp. It did use an awful lot of watt hours, much more than even the ebikeling geared hub motor. I ride ~ 8 mph typically, although I do roll hills at up to 30 mph on excellent pavement to maintain momentum from one hill to the next.
Thanks,
I checked the ebikeling.com site and the only geared motor options were 36v 500w, I didn't see a MAC motor or a high wattage geared motor. All of the others were direct drive. Besides the lack of hill climbing assist from the MXUS 36v 250w front motor that I tried before on this bike it didn't work well with the front fork. The dropouts are centered in the fork tubes on this bike so the right side of the motor housing rubbed on the inner surface of the fork tube. I spread the fork and put a spacer between the motor and the drop put to move the fork tube away from the motor the but then the right cantilever brake was displaced away from the rim. That could be compensated by adjusting the brake pad post position but it just wasn't a good fit. From my limited experience installing the front hub motor on a few different bikes it only aligned well with no rubbing if the fork dropouts were parallel with the inside surface of the fork tube (hope that makes sense). I wouldn't need a highly durable motor for this bike, it would probably be ridden less than a couple hundred miles a year at low speeds. But it would need to provide adequate assist for hills to be an enjoyable ride for my wife and me. I don't need a full feature kit, only the motor, controller, throttle, brake cut outs (already have them) and a battery, don't want or need a display or PAS function. Maybe when the supply chain improves more options will be available, right now I'm not wanting to order a 500w motor and find out that it is also inadequate.
 

indianajo

Well-Known Member
I bought my Mac12 motor from lunabike.com The 12 is more torquey low speed than the Mac10. The Mac10 will go faster. Luna can also put mac motors in rear wheels. Other reputable vendors include California ebike. Electric-bikes.com had Mac motors but wouldn't sell me one because my loaded cargo bike weighs 330 lb and I climb ~80 hills. 1000 miles after I installed the Mac12, I haven't burnt it up yet. I think electric-bikes.com has too much experience with California buyers taking their new ebike from Huntington Beach to Lake Arrowhead in 2 hours, a 1500' rise. Too much rise too quicky burns up the motor winding. Geared hub motors do not cool well.
I think the Mac12 has more torque than the ebikeling 1300 w motor ever had. From 500 watts up (it did have a display) the acceleration of the ebikeling motor did not increase noticably.
I didn't have trouble with either motor housing rubbing the front fork. If you have a standard diameter head tube front fork, you could possibly buy a fork that is wider at the top. Or scrap a $20 bike from a charity resale shop. I scrapped one just to get a seat that fits me. Make sure any front fork you buy is steel (take a magnet).
 

indianajo

Well-Known Member
This might be an option. It's a geared rear hub w/750w on 48 volts
Grin is in Canada and a electricbikereview.com poster has had trouble with customs holding his parts for 13 weeks in Memphis. If you have to send any part back to Canada for warrenty work, getting the customs paperwork correct is your problem, not Grin's. Ask somebody in Canada about the FedEx+UPS customs loan origination fee. ~$20. Suppliers I listed above are in the US.