Removing a hub-motor on a RadWagon for a BBSHD

[FlowerCrow]

Hello!

I've ordered a BBSHD mid-drive for my RadWagon 4 - which already has a Bafang Hub Motor on its rim/axle. The rear dropouts are 175mm.

Has anyone removed the hub motor and respoked a normal axle with no motor and just a freewheel on a Rad or similar bike before? Is it possible?

I'm speaking as someone with no experience on bike rims, axles, spokes, dropouts, etc.

If respoking something on the rear rim isn't possible, could I buy new rims (front/rear to match)? The rear dropouts are 175mm, front dropouts are 135mm, I'm not sure if these being different is a proprietary thing that has an effect on purchasing rims or if this is normal.

Thanks so much for your time/response it is very appreciated!

 

[2old]

The dropout widths are sizes used on some fat bikes although you could use any width rim. You just need to use your browser to get the appropriate hub. You should be able to use the same rear rim as long as the number of spoke holes is the same. Others will tell you (and be right) to use thinner spokes and maybe need washers with the old rims.

 

[caleb7]

Also you'll need to calculate spoke sizes via something like Freespoke: the spoke calculator . Existing spokes will probably be too short.

I've done what you have mentioned on a fat bike (removed hub motor, installed BBSHD). I used same rim, a new 190mm rear quick release hub and new spokes. First set of spoke nipples was too thin, I was afraid they would pass through spoke holes, so I replaced them later with thicker spokes & spoke nipples.

The problem was and still is, my dropout wasn't exactly 190mm for some reason, it is like about 185mm. That makes installing the wheel a bit harder.

 

[docw009]

I'd hate to trash a working hub wheel. You might want it later. If the Radrunner 4 uses a standard 20" rim (they claim to have 22" tires), you can try building a new wheel. A standard 20" rim is 406 mm (16 inches) in diameter, I believe. A 22" rim is actually 18" in diameter. I doubt that anyone sells them.

Grin ebikes (ebikes.ca) used to sell standard 20" x 60mm rims. Hard to find online. I bought a pair and spoked up a 20" fat tire hub, but my cursed Ecotric had a 165mm dropout. If they still sell these rims, they could probably spoke it on a fat tire axle for you.

 

[E-HP]

I'd hate to trash a working hub wheel. You might want it later. If the Radrunner 4 uses a standard 20" rim (they claim to have 22" tires), you can try building a new wheel. A standard 20" rim is 406 mm (16 inches) in diameter, I believe. A 22" rim is actually 18" in diameter. I doubt that anyone sells them.

I agree that going to a more standard wheel size would be preferred if the wheel is going to be replaced/relaced anyway. I think it's actually is a 22" tire with 25" OD though, so tire selection is limited. My 24x2.8 tires are 25"OD, but 24" rims have the same challenge with respect to limited tire selection. The 22" may have an advantage of mounting 18" scooter tires which would provide a better selection of durable tires.

 

[FlowerCrow]

The dropout widths are sizes used on some fat bikes although you could use any width rim. You just need to use your browser to get the appropriate hub. You should be able to use the same rear rim as long as the number of spoke holes is the same. Others will tell you (and be right) to use thinner spokes and maybe need washers with the old rims.

The only hub I've found online that's (36holes and 175mm dropouts) is this one:

However, it's $140 total to buy/ship to the US because it's from the Phillippines. Plus, I'm not sure if this thing is cargo bike rated, or how to tell. The material simply says alloy.

I do see a lot of bike axles in the 175mm size, I think I just need to figure out how you get the hub/freewheel mount stuff on there. I'm quite clueless and new to all of this.

Thank you all for your insightful comments! I'll do more research when I get off work.

 

[E-HP]

I did a Google search and this was the first hit:

Origin8 FB-2000 Fat Bike Hubs RR 36H Blk 8-10s Cass

HUB RR OR8 FB2000 BO 6B 36x170 8-10sCAS BK Aluminum hubs Loose ball Bolt-on

365cycles.com

OLD is 170mm so a washer on each side to get to 175mm. This is a cassette version.

 

[FlowerCrow]

I did a Google search and this was the first hit:

Origin8 FB-2000 Fat Bike Hubs RR 36H Blk 8-10s Cass

HUB RR OR8 FB2000 BO 6B 36x170 8-10sCAS BK Aluminum hubs Loose ball Bolt-on

365cycles.com

OLD is 170mm so a washer on each side to get to 175mm. This is a cassette version.

oooh I'm liking this!!

Is putting washers on dropouts pretty common practice? You may have just found me a hub

 

[E-HP]

oooh I'm liking this!!

Is putting washers on dropouts pretty common practice? You may have just found me a hub

It's common/necessary on hub motor drives to have a washer on the axle, on the inner side of the dropout, so you just need ones that fit on the 10mm bicycle axle. Referred to as the "Axle Washer" on this link: How To Install Hub Motor Washers.

PS. I have no idea what quality that hub is; it's just what came up first, so you should do your research.

 

[amberwolf]

Is putting washers on dropouts pretty common practice? You may have just found me a hub

As long as there is sufficient axle length to still put all the nuts/etc on the outboard side of the dropouts, yes.


FWIW, I recommend leaving your original motor wheel completely intact to use as a spare, since it would be directly swappable with the new one in case of problems with either the wheel or the new motor system.

You could even leave the original motor/wheel on there, and have a dual-power system, using whichever one was more appropriate at that time, or both for extra hauling power for heavy cargo or trailers.

 

[FlowerCrow]

As long as there is sufficient axle length to still put all the nuts/etc on the outboard side of the dropouts, yes.


FWIW, I recommend leaving your original motor wheel completely intact to use as a spare, since it would be directly swappable with the new one in case of problems with either the wheel or the new motor system.

You could even leave the original motor/wheel on there, and have a dual-power system, using whichever one was more appropriate at that time, or both for extra hauling power for heavy cargo or trailers.

The Origin8 Hub has arrived, and a front wheel which I plan to take a rim from is on the way, and I've noticed two things. And I know you guys have already said it should work with flat normal washers, but seeing as messing up this step could result in the wheel coming off mid-ride, I want to make certain this is right.

One, the long bolt on my hub motor has two flat edges which act as a key of sorts, like this:

And it uses a torque washer like this on my bike, rather than the one in the above image,

Which slides into the dropouts on my bike on each side, completely preventing the wheel from rotating when loose.

However, this new hub's bolt is completely round and I see no way of installing a key of sorts. It's also narrower, at 9mm vs 12mm.


Are torque washers necessary for mid-drive e-bikes, or just hub motor e-bikes?

Thank you very much for your time and patience with my limited understanding of bikes, it's always good to learn.

 

[calab]

Keeping old motor intact is the smart move!

 

[2old]

Torque washers aren't necessary for mid's. However, a nine mm axle in a 12 mm slot would be a concern for me; tight fitting washers on both sides of the dropout with the nutted axle might be safe.

 

[Chalo]

Are torque washers necessary for mid-drive e-bikes, or just hub motor e-bikes?

Flatted axles and tabbed washers and torque arms are for holding back the motor's reaction torque, which won't be at the axle if the motor isn't in the hub. A 9.5mm or 10mm round axle is what you want.

The best way to add spacing to your hub is to put (normal, round hole, 10mm) spacing washers into the axle stack underneath the hub axle locknuts. To install them, you'll need a bike specific tool called a cone wrench. Any bike shop can install them for you quickly and cheaply.

Sturdy 22" BMX rims are not very common, but still widely available. They will be substantially narrower than the Rad version, but some are wide enough to mount Rad tires if you can't buy plain rims from Rad. Also they're built strong for tomfoolery.

Note that lacing up a wheel from parts is pretty easy, but tightening it up into a good reliable wheel is difficult, and it takes a lot of practice to become proficient at it. It would be a good idea to have an experienced professional wheelbuilder do this for you, unless you plan to build more wheels later and you want to get on your game starting now.