Rear Hub Motor - Build or Buy

[gupperino]

Hello,

I've decided to say f*ck it on the frame and just convert my current hardtail into an ebike and force myself to love it. With that being said, it's a 29er with surprisingly nice WTB rims for a walmart schwinn. I've used a hub motor before on a small little eBMX project (but I used a front on the rear and threw out the drivetrain in favor of a long threaded rod!) so i don't have much experience with rear hub motors "the proper way."

I think right now I'm aiming for 48v, ideally 1500w. Here's the dilemma; I don't know whether to buy the hub motor by itself (I don't even know where to look lol) and lace it up to my existing rim. I've never laced a wheel and am not excited, but if it's cheaper than buying a prebuilt wheel then I'll do it. The other thing to remember is that 29" hub wheels are harder to come by, so I may have to go with a 26 or 27.5 if I go prebuilt. This would mean the wheels mismatch even harder than if I just had two different rims. It's kind of making me nuts.

I found this https://www.ebay.com/itm/322269304808?hash=item4b08bf57e8:g:IA0AAOSwlf5e2JHB which looks pretty close to what I need, but really all this stuff kind of looks the same. So yeah, let me be a bit more cohesive.

TL;DR:

Need 48v 1500w hub motor.

Do I buy motor by itself and lace onto my existing 29" rim?

OR

Do I buy whole wheel kit prelaced onto 26 or 27.5 rim, have the front and wheel not match and possibly different sizes, etc?

I'm still new to the forum so if there is like a breakdown of recommended products anywhere in a sticky thread that would be super useful to me. Thanks! P.S I get that this reads strangely, please excuse me, if anything is particularly unclear let me know and I will clarify.

1st EDIT:

Here's another thing I found https://www.ebay.com/itm/264501497620?hash=item3d95848f14:g:YRwAAOSwXV9gpIph that looks okay. Unsure if it has disc brake mounts which is a must for me, and it seems to come with a 7 speed something. My bike is a 1x8 so I'd need to check whether it's a cassette or a freewheel.

 

[Eastwood]

Well if you build your own wheel you can choose a quality rim to make it stronger than a cheaply built Chinese hub motor matched with a cheap Chinese rim. That being said you can buy a pre-built wheels and you shouldn’t have any issues they’re just technically not as strong.

The second link., I have that exact hub motor on one of my bikes. At 48 V you can expect around 31 mph. It has slow takeoff but once you get going it has some decent acceleration. I’ve also pushed that same motor to around 5 kW and it didn’t burn it up so it’s a decent motor.

Leaf hub motor are good, also did you check out grind technology?

Most of these 1500 W rated motors are all pretty similar. Some have more copper than others and can take more power.

As far as the wheels yes I would just go down to 27.5 in the rear and you could possibly leave 29 on the front this is not that uncommon. Or you could buy a new front wheel that’s 27.5 and get a quality mountain bike rim, or build.

 

[Manbeer]

remember, sone kits have the option for 700c which is the same as a 29" mtb so they will work out if you dont want to change wheel size. most of the super cheap ones are 26 but something like this should work

https://www.ebay.com/itm/ebike-Conversion-Kit-48V-1000W-1500W-Rear-Motor-Wheel-26-27-5-28-29in-700C-/164867467693?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l6249&mkrid=711-127632-2357-0

edit- just saw you mentioned the cassette freehub. most of the cheaper direct drive kits i see are FW. not really a huge dilemma as 7 and 8 speed gear spacing is the same so you can just adjust your derailleur to block out the top gear

 

[gupperino]

Thanks for the all the help so far. After doing some more research I’m reconsidering whether or not it’s more economical or practical to go mid drive. I’ve only used direct drive, but thinking about where I’ll be riding, city and trails, low end torque is more important in reality. Plus I wouldn’t have to change anything on the rear of my bike.

So if I can find a mid drive kit for around the same cost as a rear motor kit + wheel build + whatever annoying stuff I have to do in the back etc I’d go with that.

Seems that there is a pretty heavy premium on mid drive over direct drive.

Anyone have any thoughts on this? Like is 1500W in “hub motor power” at least in acceleration roughly equivalent to 750w mid drive power? Once again, 20-25 mph top speed would be a luxury, mostly just worried about torque.

 

[Manbeer]

for given power vs standard windings in the prefab kits the mid drive will be more practical imo

i did the DD thing first but even a bbs02 will smoke a dd with more power. also the fact you can select gears to keep the motor in its efficient zone helps keep power consumption lower for most

 

[gupperino]

for given power vs standard windings in the prefab kits the mid drive will be more practical imo

i did the DD thing first but even a bbs02 will smoke a dd with more power. also the fact you can select gears to keep the motor in its efficient zone helps keep power consumption lower for most

Right, that’s pretty convincing to be honest. At first I was skeptical about the shifting, but that sounds actually like a positive. Can’t seem to find a bbs02 for sub 400 which kind of brings me back to the hub motor + wheel build option for up to like 150 less. Will do some more research, if anyone has any sources for a good, affordable mid drive anywhere would be appreciated.

Weirdly the cyclone 3000w is competitively priced for having so much power.

I should also note that I have an 36v bionix pack and 36v 750w controller from my little bike project I could use. I wonder if a bbs02 would work on 36v while I save for an upgrade?

 

[Chalo]

for given power vs standard windings in the prefab kits the mid drive will be more practical imo

i did the DD thing first but even a bbs02 will smoke a dd with more power. also the fact you can select gears to keep the motor in its efficient zone helps keep power consumption lower for most

Right, that’s pretty convincing to be honest. At first I was skeptical about the shifting, but that sounds actually like a positive.

You will pay in parts and maintenance. Supplying more power to a hub is much cheaper in the long run, and doesn't break down nearly as much.

I used a BBS02 for a while. It works fine for folks who don't put in a lot of miles, but not so well for me because it was my everyday transportation of first resort. I found that I needed about 1.5X as much power to get comparable performance from a direct drive hub motor. Easy.

If you're the kind of person who pays his own money for a Walmart Schwinn, this is not a choice for you. You get the hub motor, because your bike will return to the dust from which it came if you burden it with a mid drive.

 

[dogman dan]

You should be happy enough with a cheapo, "48v 1000w" kit, provided you can find one in 700c/ 29 er.

Typically these cheapest kits will come with a 500w rated motor, which runs quite well up to 1500w. Labels on stuff can say anything, with these type vendors. But typically the 48v 1000w kit will come with a 30 amps, 48-52v controller. So doing the math, volts x amps, you come up with 1500w. Top speed depends on the winding of the motor, but 27-30 mph is the usual range. Acceleration will out run cars for the first 50 feet leaving a light, till they catch up going 40 mph.

Better quality, often much more expensive kits come with more reliable controllers, often more waterproof connectors, and more sophisticated displays. They can be worth it for some, because you order the kit built to your rim size choice, they use a quality rim, and provide actual warranties besides it works the first day.

But if you want it cheap, just to try it out on a cheap bike, pick any sub 300 buck kit, not including the battery. The choice will be based simply on you can get it in your rim size, from a vendor located on your continent.

 

[E-HP]

Thanks for the all the help so far. After doing some more research I’m reconsidering whether or not it’s more economical or practical to go mid drive. I’ve only used direct drive, but thinking about where I’ll be riding, city and trails, low end torque is more important in reality. Plus I wouldn’t have to change anything on the rear of my bike.

IMO, shifting is a pain if you're riding in the city or even trails. Got tired of it with cars, don't' want to go back to it on a bike (motorcycles are a different story). I basically use two gears. 90% of the time, a 13tooth cog in the rear for flat ground and up to 10% grades, ~20tooth for 10%-15%, which covers most of my riding. I will shift to a bigger cog on the really steep stuff, but for normal riding I never shift. The way I see it, similar to manual vs automatic for a car, if performance becomes a factor, get a bigger motor.

 

[gupperino]

for given power vs standard windings in the prefab kits the mid drive will be more practical imo

i did the DD thing first but even a bbs02 will smoke a dd with more power. also the fact you can select gears to keep the motor in its efficient zone helps keep power consumption lower for most

Right, that’s pretty convincing to be honest. At first I was skeptical about the shifting, but that sounds actually like a positive.

You will pay in parts and maintenance. Supplying more power to a hub is much cheaper in the long run, and doesn't break down nearly as much.

I used a BBS02 for a while. It works fine for folks who don't put in a lot of miles, but not so well for me because it was my everyday transportation of first resort. I found that I needed about 1.5X as much power to get comparable performance from a direct drive hub motor. Easy.

If you're the kind of person who pays his own money for a Walmart Schwinn, this is not a choice for you. You get the hub motor, because your bike will return to the dust from which it came if you burden it with a mid drive.

Unsure if that last paragraph is a jab or not. I’m quite happy with my hydraulic disc 29 inch hard tail.

Either way, thanks again to all the feedback everybody^^.

I’m kind of fluctuating based on my research and yeah, it seems like finding a 29 or even 27.5 hub motor kit would be cheaper upfront than going mid drive. I’ll do some more math and decide whether an unlaced motor from leaf + building into my existing rim is a cheaper option. If it is then I’ll do that for the added strength/security, if not I’ll bite the bullet and maybe peel off the ugly labels lol. While this is supposed to be a bit more serious of an ebike, that’s coming from someone who’s first was a 20 inch front hub bolted to the rear of my childhood BMX bike, wired up to a donated sketchy battery and rode it around nyc for a year. I’m okay cutting some corners and doing my research to stay economically sound.

Will update when I have more thoughts, further opinions always appreciated though!

 

[Chalo]

If you're the kind of person who pays his own money for a Walmart Schwinn, this is not a choice for you. You get the hub motor, because your bike will return to the dust from which it came if you burden it with a mid drive.

Unsure if that last paragraph is a jab or not. I’m quite happy with my hydraulic disc 29 inch hard tail.

Not a jab. It's a realistic assessment that mid drives are hard on even the most robust bike drivetrains, and a bike built to a stingy price point can't have an especially robust drivetrain.

I see a lot of BSOs in the shop, and the ones that get ridden plenty (without electric assist) grind themselves up. That's just the deal. The implication for your bike is that you don't want the motor's help deteriorating your bike, so you'd better go for the hub motor (and some trustworthy torque arms).

 

[Eastwood]

Unsure if that last paragraph is a jab or not. I’m quite happy with my hydraulic disc 29 inch hard tail.

What chalo is saying is true. It’s just that a mid drive motor is going to put a lot of stress on the frame, especially being a Hardtail there’s no give to the frame.

Like suggested by many of us it’s best to just go with the hub motor for the bike you have. It’s easier cheaper and less maintenance. If you want more torque get a kit that has a 50 amp controller and make sure you get a battery that can produce the same amps. The second link on your original post is a great option because that one comes with a 45 amp controller if you choose their 1500 W option.
Also here’s a picture of that motor.
As mentioned I have this exact motor on a Hardtail.

 

[gupperino]

Solid points all around. Sorry for my misunderstanding, just wanted to clarify this bike is a bit above a BSO so I'm not terribly worried about durability, but now it seems I'm back to the hub motor as the best option. I may go this route, if I can find a decent 48v 1000w kit for like 200 bucks (seems everything's got more expensive) I'll grab it, bad rim or not. I can always unlace it and lace it onto my existing rim anyways if it really bothers me. Guess we're going mullet either way though, as I can't find a 29er kit for less than $300, even when similarly specced to a 26 or 27.5 kit. I hope a 26 doesn't look too goofy with a 29 since that's the cheapest and most common wheel/motor combo available. Once again I can always lace to a different rim so it's no big deal all things considered. Even if it does look a bit goofy, maybe I'll embrace it and get one of those chinese downhill forks and make it as bizarre as possible.

Now to look for decent balances of cost to performance kits etc. Still need to reserve some budget for battery, probably will build one into a shark case. What's the going rate for those anyway? Last time I checked a few years ago you could grab one for like 20$ now I can't find em cheaper than 50$.

 

[Eastwood]

Here’s a kit, 29er for $300. It’s their cheapest kid they offer for 29”
They have a few other rear hub kits as well but they get more expensive

https://www.leafbike.com/products/diy-bike-conversion-kit/29-inch-48v-52v-1000w-rear-wheel-electric-hub-motor-kit-1014.html

 

[999zip999]

Plus shipping probably $150.

 

[999zip999]

Hub motors work for a long time a controller would probably last a long time but the heart of electricbike is the battery. You cannot go cheap on a battery pay the money. How much money do you have ? Where do you live ? Yes important.
Easiest and best if you could stick with a 26in. An old chromoly mtb strong and cheap.

 

[999zip999]

Eastwood and gupp you both NEED a torque arm so you don't spit it. crazy Lenny had electric step through ebike 36 volts for $650 or so. low power probably just 18- 22 miles an hour
guessing.
How fast and how many miles do you plan on go is it flat land do you have hills ?
buy a decent battery you cannot make a battery out of a used computer cells. Cells that are meant to push 220 lb around.
https://endless-sphere.com/forums/viewtopic.php?f=9&t=107299
if you want to make a battery where is battery builds on putting 14 in these together that'd be a 48 volt 15 amp hour battery you have to get a shoe box or two and cut up a cardboard maca of this size the battery then see if that size battery will fit in the triangle your frame or where you may have room for the cardboard box of a battery before you buy and where you going to put the controller. Answer these questions and it'll be easier built plus but not on the rear of motor must be able to fit in your rear axle slot and the derailleur cannot be in the way of this or the nut would not go on. As not all bikes were made to have a motor put on them.

 

[gupperino]

Eastwood and gupp you both NEED a torque arm so you don't spit it. crazy Lenny had electric step through ebike 36 volts for $650 or so. low power probably just 18- 22 miles an hour
guessing.
How fast and how many miles do you plan on go is it flat land do you have hills ?
buy a decent battery you cannot make a battery out of a used computer cells. Cells that are meant to push 220 lb around.
https://endless-sphere.com/forums/viewtopic.php?f=9&t=107299
if you want to make a battery where is battery builds on putting 14 in these together that'd be a 48 volt 15 amp hour battery you have to get a shoe box or two and cut up a cardboard maca of this size the battery then see if that size battery will fit in the triangle your frame or where you may have room for the cardboard box of a battery before you buy and where you going to put the controller. Answer these questions and it'll be easier built plus but not on the rear of motor must be able to fit in your rear axle slot and the derailleur cannot be in the way of this or the nut would not go on. As not all bikes were made to have a motor put on them.

Yeah, I know about torque arms and such, I’ve got some experience with ebikes, just haven’t purchased anything in quite a while. I’m still likely to build my own battery. I’ve built them in the past and am confident in my ability to pick out some good cells. Will see how things go, I’ve sent some messages out to eBay sellers asking about their wheels. Hopefully they get back to me soon. Not excited about wiring up my own reed switch hydraulic ebrake setup haha.

 

[999zip999]

OK a Walmart bike 29 in which one do you have you have hydraulic disc brakes ? How about a link to your bike or pics. Do you have a spot welder how would you build your battery what exact cell would you use.
https://endless-sphere.com/forums/viewtopic.php?f=14&t=38761&start=25#p573523
with those cells I link earlier you can bolt together a battery pack like this if it will fit in your bike for cheap.

 

[dogman dan]

I went through some bikes pretty fast, commuting a lot of miles, till I put the kit on a higher quality bike. It was the actual frames I was wearing out, btw. But drive train stuff did need work on it, you sure can't keep going on a wheel or bottom bracket that gets loose very long.

My advice was based on the one think I kept seeing repeated. He wanted it cheap. Get that cheap wheel then, and eventually maybe put it on a better rim. Your old rear wheel can be used as a practice piece. Take it completely apart, and using the front wheel as a guide, rebuild it again and true it. Then you are ready to order spokes for that 29 rim and lace the motor in your good rim.

Meanwhile, you may be surprised how long the cheap wheel lasts, if you keep up with spoke checking and keeping it snug.

 

[gupperino]

OK a Walmart bike 29 in which one do you have you have hydraulic disc brakes ? How about a link to your bike or pics. Do you have a spot welder how would you build your battery what exact cell would you use.
https://endless-sphere.com/forums/viewtopic.php?f=14&t=38761&start=25#p573523
with those cells I link earlier you can bolt together a battery pack like this if it will fit in your bike for cheap.

Schwinn Santis. Surprisingly decent sans low travel fork. As for the battery, I was thinking I’d just tape a bunch of AA’s together. But really, that’s actually the area I’m most confident in and least worried about. I have one of those cheapie portable spot welding power banks that works just fine even on thicker nickel.

I went through some bikes pretty fast, commuting a lot of miles, till I put the kit on a higher quality bike. It was the actual frames I was wearing out, btw. But drive train stuff did need work on it, you sure can't keep going on a wheel or bottom bracket that gets loose very long.

My advice was based on the one think I kept seeing repeated. He wanted it cheap. Get that cheap wheel then, and eventually maybe put it on a better rim. Your old rear wheel can be used as a practice piece. Take it completely apart, and using the front wheel as a guide, rebuild it again and true it. Then you are ready to order spokes for that 29 rim and lace the motor in your good rim.

Meanwhile, you may be surprised how long the cheap wheel lasts, if you keep up with spoke checking and keeping it snug.

All this is good advice, though I’ve never built a wheel I can true and tension them, so I’ll give whatever I get a full once over. I hope the mullet doesn’t look too wonky, 26 rear 29 front. It’ll likely only be temporary though, as you’ve mentioned.

 

[999zip999]

Gupp answer some of the needed questions do you have hills or just flats how many miles do you want to go how fast do you want to go ? how much weight will you be hauling this is very important if you have hills. How big is the triangle in the bike that you now own ? How much money do you want to spend. Do you live in southern California ? As my neighbor has some electric rental bike deals he uses them 3 to 4 months in sells them. He's not going to box it up and mail it

 

[gupperino]

Gupp answer some of the needed questions do you have hills or just flats how many miles do you want to go how fast do you want to go ? how much weight will you be hauling this is very important if you have hills. How big is the triangle in the bike that you now own ? How much money do you want to spend. Do you live in southern California ? As my neighbor has some electric rental bike deals he uses them 3 to 4 months in sells them. He's not going to box it up and mail it

This is the bike I’m planning on using for the conversion, I’m not worried about laying everything out like I said, mostly just picking a motor.

Here’s my current very real electric bike 100% solar powered it just happpens to sound like a 2 stroke.



Mostly flat here, idk like 150lbs maybe 200 with cargo, nothing too crazy. Thanks for the kind offer, but unfortunately I’m not in Cali. NYC actually!

I think I can get this whole thing done for sub 4 or 5 Benjamin’s. Abt 250 on a kit abt 150 for battery build no biggie. Right now I’m looking at some cheapo 26” inch kit on eBay.

 

[Chalo]

abt 150 for battery build

Um, that seems like just enough to be disappointed when you put it together. What did you have in mind? Salvaging waste cells, going without BMS, not using a proper case?

I sometimes come across used commercial batteries in that price range, but that's a really low price even for salvage.

 

[999zip999]

I gave him a link for used LG cells in the youth section of endless sphere
15ah 10c cell $10.00 ea
no spot welder need it you can just both these things together between aluminum and plastic blocks. Will 14s fit in the triangle you don't have to make a box out of cardboard the size of the cells see if it fits in the triangle ? I also gave you a building link for pouch cells. I just can't buy them and put them together for you. Spoon feed.
I even chewed it first for easy swallowing.