Used Jump Bafang Hub for Budget Build?

[Chalo]

I think time spent on "re-inventing" the "Jump" wheels is mis-placed. The materials and spoke patterns used are fine for their intended usage, after all,

That's arguable. Certainly none of these wheels saw very much mileage, and yet some of them arrived in poor shape. Not a great sign.

Anyway, not every bike uses 26" wheels or disc brakes, so there are plenty of reasons to swap rims apart from their bad wheel build. If you need a different rim anyway, might as well get the spokes right while you're at it.

 

[E-HP]

That's arguable. Certainly none of these wheels saw very much mileage, and yet some of them arrived in poor shape. Not a great sign.

I don't think mileage is the issue. For most riders, it's their first time on ebike. One of my daughters tried one. First time on an ebike, and first time on a bike for 6 or 7 years. She wasn't expecting the assist and proceded to run into the bumper of a parked vehicle. I don't think that's an uncommon scenario, and that was only a few feet of mileage.
They also see a lot of unintended use. Practically every homeless camp has one.

 

[ynot]

@ Chalo,
Tried to order jump wheels from JAG and was redirected to BCH, so emailed BCH & was told that JAG is an associate vendor of BCH stuff, & the reason I got redirected is because JAG had none at that time.
Hopefully this is not the end of the jump wheels.

 

[Chalo]

Tried to order jump wheels from JAG and was redirected to BCH, so emailed BCH & was told that JAG is an associate vendor of BCH stuff, & the reason I got redirected is because JAG had none at that time.
Hopefully this is not the end of the jump wheels.

It might be. But there will be other commercial implosions for as long as dockless rental e-bikes are in the huckster economy.

 

[spaceship]

Time would be better spent on how to true the whl.s, something that goes across the board for ebikes and will serve builders well in the future.

I appreciate all the discussion on various topics, however as the OP on this thread the fact is that the jump hubs I ordered are coming rimless. So building a wheel is essential in my case and Chalo's input on spokes/wheel building is extremely useful to me and more relevant to this thread.

I will be documenting my process of building a wheel for the first time from a blank jump hub. Does everybody need to do that? Certainly no, they are likely very usable as is. But in this case yes it is necesary and possibly somebody else will find this thread helpful if they need to do the same.

I will hopefully get a rim and spokes soon and will post as I progress on the wheel build.

 

[docw009]

I appreciate all the discussion on various topics, however as the OP on this thread the fact is that the jump hubs I ordered are coming rimless. So building a wheel is essential in my case and Chalo's input on spokes/wheel building is extremely useful to me and more relevant to this thread.

I happened to take the rim off a bafang Jump wheel last summer and spoked on an ebikeling rim, which was also an ebike rim, so I stayed with 13G spokes.

The Jump rim later got spoked onto a regular 26" hub over the winter. In that case, I found 13G spokes wouldn't fit the hub, so I went with 14G spoke, which were too small for the 13G holes in the rims, but the spokes were also too long, so washers saved the day, It was complicated by me wanting to do a double cross lace, and I only succeeded by copying another wheel.

Unless you get a rim with 13G spokes, you will probably want Sapim Strong spokes, which are 13G at elbow and 14G at the end. Most of my opinions on spokes came from Chalo's 'rants" on the topic. They made sense to me. It does help to have a single cross wheel to look at while you're laying out the pattern, but unless you have a second hub motor, you probably don;t have one, Good luck!

This gal was my heroine. I followed her instructions for first two or three wheels.
https://www.youtube.com/watch?v=mIU6mi0K4Y4&t=53s

 

[Chalo]

The Jump rim later got spoked onto a regular 26" hub over the winter. In that case, I found 13G spokes wouldn't fit the hub, so I went with 14G spoke, which were too small for the 13G holes in the rims, but the spokes were also too long, so washers saved the day,

Anymore, I use these 2mm flat washers under the spoke heads when the hub holes are big, and these nipple washers when I have a rim with big fat holes.

The conical nipple washers are the next best thing to an eyelet, so sometimes I use them in plain drilled rims whose holes aren't oversized, but whose spokes need to be really tight.

 

[calab]

I bought my flange spoke washers from the Home Depot bolts and washers aisle. They rusted but they have lasted.

You can use a flaring tool to bend your own washers for the nipple, 36 takes time.

 

[amberwolf]

The conical nipple washers are the next best thing to an eyelet, so sometimes I use them in plain drilled rims whose holes aren't oversized, but whose spokes need to be really tight.

Would those work for an Alex DX32 20" rim like this?
https://endless-sphere.com/forums/viewtopic.php?f=2&t=67833&p=1711799#p1711726
https://endless-sphere.com/forums/viewtopic.php?f=2&t=67833&p=1711799#p1711799
In case I need to keep using it on the SB Cruiser build, rather than putting one of the rims you sent me on that new motor (I'm in the process of putting one of them on the other similar motor that had been on there, to replace the damaged identical rim that's on there now).

These appear to be a purchaseable version of those
https://www.amazon.com/SPOKE-NIPPLE-WASHER-SS-BGof100/dp/B00KSJSFQ4
are they the same or did I miss something?

(the jbi.bike link has no way to purchase the product that I can find)

 

[calab]

An option for those with spoke angle issues.

https://wheelbuilder.com/sapim-brass-polyax-nipples/

Sapim's original Polyax brass nipples have a rounded profile, which allows up to 9 degrees of rotation for improved spoke alignment and durability.

 

[Chalo]

Would those [conical nipple washers] work for an Alex DX32 20" rim like this?
https://endless-sphere.com/forums/viewtopic.php?f=2&t=67833&p=1711799#p1711726
https://endless-sphere.com/forums/viewtopic.php?f=2&t=67833&p=1711799#p1711799

Sure. I've not come across a rim they don't work with.

These appear to be a purchaseable version of those
https://www.amazon.com/SPOKE-NIPPLE-WASHER-SS-BGof100/dp/B00KSJSFQ4
are they the same or did I miss something?

(the jbi.bike link has no way to purchase the product that I can find)

Those are the ones. I used the JBI link because that's where I get them, and pretty much any bike shop in the country can get them there. That Amazon price is full retail, but if it includes delivery then that's a relative bargain.

The Sapim nipples calab recommended are pretty ordinary with respect to their ability to gimbal in the spoke hole (which is limited by the nipple and hole diameters and the rim thickness), but they're harder and more resistant to rounding off than DT Swiss nipples, so I prefer them for that reason.

 

[spaceship]

I have been busy the last while, but finally got around to measuring the hub and plugging everything into the grin spoke calculator. I just followed the directions and watched the videos from the page and it was pretty straight forward to figure out. I will be re-using a rim that I have - a 26" Alex DM18 that is in good shape true and round. Here is a link to the spoke calculator with my measurements. 204.4 & 205mm spokes.

https://ebikes.ca/tools/spoke-calc.html?hub=cust_d145_s46_o6_n36_l145_h3_p25.3&pair=false&rim=26DM18&cross=1&lelb=out&relb=in

I will order up 205mm spokes and nipples from my local bike shop. checking with a 14g spoke it seems to fit fine in the holes on the hub, so I don't think I will use any kind of washers there. Just standard 14g spokes and nipples, and maybe some spoke nipple washers for reinforcement at the rim, since the rim is just drilled holes.

 

[Chalo]

checking with a 14g spoke it seems to fit fine in the holes on the hub, so I don't think I will use any kind of washers there.

Normal 14ga spokes bury themselves into the hub holes and are at some risk of pull-through. Even if they don't pull through, they can lose tension as the heads dig deeper into the flange. Go ahead and use 2mm or #2 washers; you'll save yourself future problems that way.

 

[spaceship]

checking with a 14g spoke it seems to fit fine in the holes on the hub, so I don't think I will use any kind of washers there.

Normal 14ga spokes bury themselves into the hub holes and are at some risk of pull-through. Even if they don't pull through, they can lose tension as the heads dig deeper into the flange. Go ahead and use 2mm or #2 washers; you'll save yourself future problems that way.

Maybe I will just grab the Sapim 13/14 spokes from Grin and a new rim while I'm at it. For my first wheel build I might as well make it easy on myself and just get the ideal spokes and not mess with a used rim. I will be spending the weekend in Vancouver 2 weeks from now, so if I want to save shipping I can pick up from them direct. Although I might just pay for shipping so I can start working on it.

 

[spaceship]

PROGRESS UPDATE:

I finally found the right bike. Picked this up for $100. Needs a good tune up but the size is right (rider is 5"3") and it has some good components. Marisocchi fork, hayes hydrolic disc brakes. I dont know what the frame is, the only marking says its 6061 heat treated tubing. Needs a good tuneup, new brake pads, shift cable but I am really happy with this bike for the build.



I also got started on building the wheel. I ordered the Sapim strong spokes from Grin ($46 plus shipping for 36 spokes). I found it quite hard to find a 36 hole rim to buy - called every local bike shop with no luck. I opted to use a good used Alex dm18 rim that I already had, and it was a preset option in the spoke calculator so I didnt have to do any measuring. Unfortunately Grin shorted me a spoke, only sending 35 spokes. I got the rim laced up but cant finish the wheel until I get the final spoke. I contacted GRIN and they already sent out two spokes (so now I have a spare at least)





I also picked out and ordered a downtube battery box and controller. I had some thoughts about doing a custom shape diy battery box, but ultimately decided to go with a premade box in order to make my first battery build a little eaiser and keep it sturdy and safe. I found this Polly DP-6C battery box that can have a kt controller built in to the battery base. I really like the idea to keep the build very clean and minimal, and to make it easy to swap to a different bike if I want to.



I ordered through the topbikekit.com and was able to get everything I need in one place. Came with the battery box, cell holders, precut nickel strip for a 13s5p pack, 30A 13s bms, KT 22A controller, lcd5 display, half twist throttle (slim version that wont interfere with trigger shifter) 9pin motor extension cable, 2to1 cable for throttle and display connection. I am going with no pedal assist or brake sensors, just throttle and display for simplicity.



I measured out the battery box and it will be a tight fit. Here is hoping the actual box fits. The drawing only gives the overall height and length, so those dimensions are accurate but the tapered angles are just eyeballed from the drawing. And I know it will need to go further up the downtube in order to slide down into the holder, so... I may have to get creative with mounting. There was a smaller 52 cell hailong box available, which would be fine except that the only compatible controller that the seller had was only 7A continuouos 15A max. I really wanted to get the 22A controller on this build. So all I can say is I hope it all fits!

I'll update in a few weeks with everyting arrives!

 

[Chalo]

Hydraulic brakes and forks don't age well, so be ready to cut your losses and switch to something more future-proof. I doubt any of them is supported with rebuild kits anymore.

How are you going to keep the motor axle from breaking off the fork tips? The axle studs are short enough that you don't have many options.

 

[spaceship]

Hydraulic brakes and forks don't age well, so be ready to cut your losses and switch to something more future-proof. I doubt any of them is supported with rebuild kits anymore.

How are you going to keep the motor axle from breaking off the fork tips? The axle studs are short enough that you don't have many options.

yeah I would be prepared to repair/replace components as needed. Also am plannning to make the kit easy to swap to another bike, so that adds future proof.

as far as fork arms for the torque tips - Ill try and figure something out, or keep the power restricted.

 

[docw009]

It's funny how our budget builds just creep away from the original intent. Here I am spoking a new hub into a 26" rim so I could have disk brakes in the back. As least I got the rotor with the BCH hub, And then I went with hydraulic hose/caliper. That made me finally adapter a caliper to the front fork, Finally have decent brakes now.

 

[calab]

He's smart, he posts pictures :thumb: :wink: 8)

 

[spaceship]

It's funny how our budget builds just creep away from the original intent.

Haha i know right? I was thinking about this when writing the update. It has definately shifted from a "budget build" because its my first time building a wheel, first diy battery pack. There is a extra cost to learning new things - tools needed, mistakes made, the shipping expenses to get everything you need in a timely manner. But there is value gained in it.

Even still tho, the hubmotor was $24 usd ($30 cad), spokes $47, the rim already had. Nuts and washers $3. So aside from shipping costs a 500watt wheel for $80 CAD is still pretty budget.

And ya, I could have found a cheaper controller, used a throttle that I already have, and DIY the battery box - as was my original plan. But my girlfriend is a little weary of battery safety, having seen some clips of ebikes on fire. Putting it together in a clean, factory looking package will just make her feel more comfortable vs something that looks homemade.

And still I bet if I added up the cost of the salvaged cells and the battery box it still would be pretty good for a pack with genuine LG cells. Its bringing all the pieces together and paying shipping from different suppliers that really adds up. But hey its a hobby and a learning journey.

 

[simonov]

Hopefully this is not the end of the jump wheels.

It is from BCH. I just got this e-mail:

The wheels were a one time purchase, at this time we don't have any plans to bring more in.

 

[Chalo]

Hopefully this is not the end of the jump wheels.

It is from BCH. I just got this e-mail:

The wheels were a one time purchase, at this time we don't have any plans to bring more in.

It was a windfall that came along when Uber sold its Jump bike business to Lime, but that sale didn't include the bikes. Those were scrapped, and liquidators got the wheels and batteries.

 

[99t4]

But my girlfriend is a little weary of battery safety, having seen some clips of ebikes on fire. Putting it together in a clean, factory looking package will just make her feel more comfortable vs something that looks homemade.

That right there is worth a LOT! :thumb:

 

[spaceship]

But my girlfriend is a little weary of battery safety, having seen some clips of ebikes on fire. Putting it together in a clean, factory looking package will just make her feel more comfortable vs something that looks homemade.

That right there is worth a LOT! :thumb:

Its actually a pretty good deal all in. For $138USD (plus shipping) im getting the 22A Controller, throttle, display, motor extension cable (that matches the 9 pin cable on the motor), controller to display & throttle cable, 30A BMS, custom cut nickel strip to match the cell arrangement, cell holders, battery case (with power switch, battery level indicator), and the base for mounting it to the bike. Unless just "happened" to have all the materials I need laying around, DIY battery box would add up to more I think. (unless just making a sketchily duct taped together battery)

Even looking at their prices for fully built battery with built in controllers, If I didn't want the experience of building a battery it would make so much sense to just order it complete from them.

 

[spaceship]

I did end up going with a controller with 9 pin plug and fits into the base of the downtube battery