Ebike motors for 110mm spacing
- Thread starter petehouk
- Start date
Help Support Rat Rod Bikes Bicycle Forum:
I bought a FRONT hub motor, already built up into a 26" 559 wheel, for a vintage bike conversion project. It was 100mm OLD, requiring some fork bending, but nothing that seemed excessive to me. I didn't find any rear hub motors that were narrow enough, especially since there was no provision for rim brakes on the machine I was working on.
The rear hub motors I was finding generally had provision for either cassette or freewheel on right side and disk on left, and started at around 135mm OLD.
The rear hub motors I was finding generally had provision for either cassette or freewheel on right side and disk on left, and started at around 135mm OLD.
This is what I have seen as well. But many of them have a 7s freewheel, which fills up a lot of the 135mm of width. I don't have much experience with ebike hubs, but the other freewheel hubs I have seen have a spacer on the axle so that the lock nuts stick out of the freewheel. (As in the attached pic.) If I put a single speed freewheel on there, could I remove some spacers and skinny up the overall length? Get it closer to 110?
I see what you are saying, and it seems like a good possibility. The freewheel end of this MXUS XF08 does look like perhaps there is a spacer secured with a locknut.
If you remove the nut and 1) the spacer is removable and 2) can be finagled over the electrical cable, and 3) the axle is threaded down far enough, it appears a possibility that you could get your OLD down into the neighborhood of 115 - 120 mm.
This MXUS motor is ~ $95 - $120, depending on the power rating. https://www.ebay.com/itm/254942749063
But unless you sever or remove the cable assembly and re-terminate it, you would still have a long protrusion sticking out the right side of the bike, which would be prone to accidental damage.
There are hub motors available with the cable on the opposite side. I would think that this would be an easier modification, if the construction facilitates what you are describing. unfortunately, I'm not finding any images detailing what is under the sprocket cluster.
There's one other possibility that I can think of. Attaching a sprocket to the 6 screw pattern for the brake disk provided on a FRONT wheel hub.
Not sure how viable this idea is, either mechanically, or electrically, since it would likely require the hub to operate in reverse.
Perhaps, if there is somebody dealing in e-bikes in your area, you could get some condemned hubs to investigate? I understand that replacing deceased hub motors is a pretty regular event in the e-bike world.
I'm sort of warming up to the idea of using a front hub. I think I have read about that elsewhere. You either need to find a compatible cover that has the freewheel threads on it or make an adapter and use the disc brake holes, and then run it in reverse. It's a DC motor, you can just reverse the +-, right? Or anyway that's what I learned in physics class in high school.
I stopped by the local eBike store today and they did not have any good 110mm options for me. They said they would convert my bike for ~$1400. They won't sell me the parts to do it myself. eBikes are crazy popular around here and I think they are having trouble keeping up with demand, so I totally get why they don't want to put a ton of effort into a one-off job like mine.
I stopped by the local eBike store today and they did not have any good 110mm options for me. They said they would convert my bike for ~$1400. They won't sell me the parts to do it myself. eBikes are crazy popular around here and I think they are having trouble keeping up with demand, so I totally get why they don't want to put a ton of effort into a one-off job like mine.
I guess that some of the lower end hub motors are indeed simple two terminal brushed motors.
But more sophisticated bike hub motors use brushless 3 phase motors.
This allows much more control, better efficiency and longer life, with no brushes to wear out. This video describes the basic concept:
DC is chopped and pulsed into the 3 phases under control of the dedicated controller. The controller does the magic, including the speed control function. I'm not sure how reversing the direction of a brushless motor would be done, but I imagine it's done in the controller software. Here's wiring of a typical controller.
Brushed motor controllers will be simpler. Here's an example of a brushed motor controller:
It's still a lot of wiring to sort out. You'll want to make sure that the components you choose are compatible and will give you the result you expect.
E-bikes are definitely up and coming. I went with a front wheel kit (for front installation) to keep things simple for my first conversion, but it's actually been sitting on a shelf as other projects keep popping up.
If you aren't dedicated to the idea of converting a vintage bicycle, I'm thinking that one can actually get up and running for less money, and definitely less effort, by taking advantage of sales as manufacturers adapt to the emerging market. For example, when RAD discontinued their RadMission model last spring, they offered them up for $499, complete, with some assembly required. I seriously considered buying one, but the single speed hub put me off. Still, with its front and rear disc brakes, 500w motor, and lithium battery, that's a lot of stuff for the money, and they threw a bike in as well. Apparently other people thought so as well, as they sold out in about 5 days.
The RadMission 1 is a $1,099 e-bike that delivers the basics | Engadget
I’m pleased to report that Rad Power Bikes’ estimates are accurate.
www.engadget.com
This is good information! I guess I figured it was more complicated than just reversing + and -. Oh well.If you aren't dedicated to the idea of converting a vintage bicycle, I'm thinking that one can actually get up and running for less money, and definitely less effort, by taking advantage of sales as manufacturers adapt to the emerging market. For example, when RAD discontinued their RadMission model last spring, they offered them up for $499, complete, with some assembly required. I seriously considered buying one, but the single speed hub put me off. Still, with its front and rear disc brakes, 500w motor, and lithium battery, that's a lot of stuff for the money, and they threw a bike in as well. Apparently other people thought so as well, as they sold out in about 5 days.
The RadMission 1 is a $1,099 e-bike that delivers the basics | Engadget
I’m pleased to report that Rad Power Bikes’ estimates are accurate.
Here's a kit that says it is for BMX and the spacing is specifically called out as 110mm. I am thinking I could buy this kit and lace the hub into my own rim. Does anyone have any experience with Leafbike?
www.leafbike.com
BMX 26 inch 48V 52V 1500W rear hub motor - electric bike conversion kit
Convert your 26 inch original bike to be ebike with leaf 26 inch 48V 52V 1500W rear bmx hub motor electric bike conversion kit rear drive.
www.leafbike.com
Good find! This looks like just what you are looking for. Unlacing wheels and relacing to a new rim is a tried and true method of modifying the performance of a motor. For example, to violate the software imposed speed limit, lace the motor from a smaller wheel to a larger rim. (I know this isn't what you are going for here.)
It seems that Leaf Bike is the retail side of Leaf Motors. I'm finding what looks like the corresponding motor on Leaf Motor, but not the narrow "BMX" build.
https://www.leafmotor.com/48v-52v-1500w-rear-e-hub-electric-bike-motor-p00105p1.html
https://www.leafmotor.com/single-cog-p00143p1.html
The Leaf LMM481500R hub looks like a direct drive (no planetary gears), 3 phase powered design to me. According to this 3/22 review, it contains some refined features which improve torque and efficiency. https://www.electricbike.com/leafbike-1500w-hubmotor-the-mid-sized-hot-rod/
If you want to look at some basic discussion and options in hub motors, this article is a few years old, but covers a lot of the basics: https://ebikes.ca/getting-started/hub-motor-options.html
I've only been on Rad Rod Bikes for a few months, but I find it to be a great source of knowledge and folks are very willing to share. Still, for very specific detailed info like this, I'd probably seek out a forum more focused on electric bicycles. I won't link direct to another forum, but a Google search showed me that some folks communicating in a group called "Endless Sphere" have had experience with Leaf motors. There's lots of very detailed discussion of suitability and performance of various motors, including Leaf products there.
1500 watts is a pretty substantial 2 hp. USA legal definitions of electric bicycles limit them to half that, 750 watts. Most manufacturers use the controller to limit the power, and enforcement of these federal definitions affect manufacturers at this point, not riders who build their own. Still, things like the power and speed limits are there to protect the little guy from relying too much on his guardian angel. What plans are you making to upgrade braking capability on your Heavy Duti?
The Heavy has had a Worksman front drum hub for a decade or so. This contributes to my desire for a rear hub motor since there's no hole in the fork for a brake caliper. (Also contributing is the fact that I don't want to file open the fork to fit the larger diameter of an electric hub axle.)
The Bendix red band will be replaced by the hub motor and freewheel but this frame has a mount for a caliper for the rear wheel.
The Bendix red band will be replaced by the hub motor and freewheel but this frame has a mount for a caliper for the rear wheel.
This guy talks about building and riding that rig on U-tube:
The clamp on rear sprocket has been the go-to method for adding a chinese two stroke gas engine for quite some time, and I understand it is one of the most common sources of problems. I heard of a few ways to improve the situation;
- Heavy duty spokes
- A sprocket that clamps on the hub. https://www.bikeberry.com/products/bbr-tuning-sprocket-adapter-assembly?_pos=1&_sid=ea8b58d0f&_ss=r
- One that mounts to the disc brake 6 bolt pattern https://www.amazon.com/CDHPOWER-Ada...-Bicycle/dp/B08N4VSCCY/ref=asc_df_B08N4VSCCY/
But most solutions will, once again, put you up against the 110 mm dropout width constraint.
The gear motor in the kit doesn't look as cheap as some, but it is a brushed motor, and I would expect those and the bearings to wear out at some point. The controller looks tiny. Read the reviews to get an idea what to expect.
It's even cheaper from Walmart: https://www.walmart.com/ip/Electric...-Motor-Motor-Controller-w-Freewheel/764867348
The easiest retrofit has gotta be a friction drive kit: https://www.clip.bike/
