What rear brakes can I install on this bike frame?

[Cursor-I-Am]

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Hello. I replaced the rear wheel of my stock ebike that originally came with a drum brake built into the rim of the wheel. The bike was given to me by a 70 year old who man rode it for a month, fell off it (messed up the wheel internals) and his wife made him give it up. I know his wife and she knows I needed transportation so they told me it's mine, "Just replace the rear wheel." So I did. Everything else was in pristine condition.


I have little funds but I managed to replace the wheel. However, this means I lost the drum brake. I am down to my last $40 after all of this and with shipping delays, and no bike shop nor mechanic in my city, I need to find a type of brake that is compatible with my bike frame. I do not have the time nor monetary resources to buy a brake, find out it doesn't work, then return it, then try a new brake etc. So I am asking for help from you guys as this community seems knowledgeable.

Thank you.

 

[Chalo]

The rack mounts make mounting a caliper on the top side impossible. It might be feasible to mount one on the underside of the seat stays. In the past, I once put a BMX caliper on the kickstand plate of a similar bike frame by using stepped washers for spacing.

If you can figure out what you need to do, it may be more cost effective to repair the original wheel than to adapt the bike with a different kind of brake.

If you depend on a cheap e-bike to function so that you can get to work, you're going to be late for work and you're going to spend a lot of money keeping it operational. If you have a very tight budget and your health allows, you would be wise to sort out a pedal bike for yourself rather than an e-bike. It's categorically cheaper and more reliable that way.

 

[LewTwo]

If you can figure out what you need to do, it may be more cost effective to repair the original wheel than to adapt the bike with a different kind of brake.

One of his first posts mentioned: Nakto Men's Camel

This is from a company that seemingly does not even know their left from their right (ref the majority of their online adds). Thus I would not count on any support from the dealers or manufacturer. I did find one picture of the bike in the correct orientation ...

This is the original rear hub and drum brake. It is indeed a drum brake but I do not recognize the hub or the brake assembly.

135mm Rear Hub Spacing, 12mm Keyed Threaded Axle with 18mm Nuts
Steel frame with a one inch threaded coil spring front fork.
At least the front brake should still be intact.
May need to ditch that rear rack

According to EBR the rear geared motor hub was branded 'AOMA' and equipped with a Shimano six speed derailleur.
https://electricbikereview.com/nakto/camel/

 

[Cursor-I-Am]

Thanks. The drum brake rotor screws onto the hub of the old one. I tried making an adapter for it with a bottom bracket bearing and a disc brake flange but the axle did not have enough space.

Here is what the rotor looks like on the old bike.

https://i.imgur.com/zq44rhI.png

The rotor screws onto a 34mm thread. The drum brake shoes push against the rotor to stop the bike. The two holes on the rotor are too far apart to be screwed into the 6 holes on the motor.

So I made an adapter for for the rotor. I bought a 6 hole disc brake flange which has a thread in the center of it. I then bought a bottom bracket bearing. I mounted the flange and screwed the bearing in.

https://i.imgur.com/fQzHngl.png

I managed to mount the rotor on:

https://i.imgur.com/NI9unyE.png

But I ran out of axle space and the wheel couldn't be centered. I went to Lowe's and bought the flattest head screws I could find:

https://i.imgur.com/aV9bMKB.png

But it was still not enough.

https://i.imgur.com/qiewuO1.png

The old wheel is toast and isn't compatible with the new motor. This bike is my only transportation around my hilly area. I use it for groceries. If I can only get brakes if I remove the rack, then are there any alternatives for racks?

 

[LewTwo]

If I can only get brakes if I remove the rack, then are there any alternatives for racks?

One might try relocating the front rack mount to the seat post with something like this:
https://www.amazon.com/dp/B001V537I0
or
https://www.amazon.com/dp/B000AO9PE8
or
https://www.amazon.com//dp/B0014GI9RK

Try searching Amazon or Ebay for "Seatpost Clamp Rack"

 

[Cursor-I-Am]

If I can only get brakes if I remove the rack, then are there any alternatives for racks?

One might try relocating the front rack mount to the seat post with something like this:
https://www.amazon.com/dp/B001V537I0
or
https://www.amazon.com/dp/B000AO9PE8
or
https://www.amazon.com//dp/B0014GI9RK

Try searching Amazon or Ebay for "Seatpost Clamp Rack"

Thank you. I at least now have an idea of what to do after these replies.
As a noob question, what are the issues I would run into using a disc brake adapter? Like this one:
https://www.amazon.com/Star-Art-Adjustable-Bracket-Converter-Mounting/dp/B07YVFVRD1/ref=sr_1_6?crid=3BJJWLM14PV80&keywords=disc+brake+adapter&qid=1636981369&sprefix=disc+brake+a%2Caps%2C178&sr=8-6
And clamping it to the frame?

Are there any bike racks that would add another method for brakes?

Also, would it be possible to use a long bolt and/or bolt with spacers to go through the rack mount and a disc brake hole? My dropouts are kinda far apart even though the online measurements would lead one to believe otherwise. They squeeze together a bit when tightening. Not sure if I'm explaining myself well but I hope it's understandable.

 

[Cursor-I-Am]

I was just looking at one of Nakto's disc brake bikes and had an idea.

https://i.imgur.com/Lrg19hr.png

My bike rack can be heightened for clearance. This will free up a few mounting holes which I could maybe use for a disc brake caliper?

https://i.imgur.com/9cIpVdV.png

That said, the hole that it would free up maybe wouldn't be the exact angle/distance needed, but the extra holes there could potentially allow me to use an adapter?

 

[LewTwo]

I have never had or used disk brakes.
One reason is that I was never able to find any published standards for them.
Thus I must recuse myself from any response in that regard.

 

[Chalo]

Disc brake adapter mounts like the one you posted above are easy to bend and don't have the stiffness required to do the job they purport to do.

You don't have the budget to see your project through. It sounds like you're already using a rear hub with the wrong spacing for your bike's frame, which is inviting the frame to break at the forward end of the chainstays like markz's frame did. Slow down, save up some simoleons, and learn enough to head off major problems before they happen.

The kind of brake your bike originally had is called a band brake, and it fits on a thread that's identical to a freewheel thread but located on the left side of the hub. Many of the first generation of cheap Chinese e-bikes had rear hub motors with band brakes, but most have since substituted disc brakes because discs have become a checklist item for low-information buyers. You may be able to buy a non-working e-bike with a band braked motor for less that it would take to add a brake to the mismatched equipment you've got.

 

[docw009]

Thank you. I at least now have an idea of what to do after these replies.
As a noob question, what are the issues I would run into using a disc brake adapter? Like this one:

.

The problem is that the angle they used for the slot doesn't fit most bikes, especially on the front forks, and it's flimsy. Still, the idea has merit. One guy wrote an amazon review showing how he used it as a template to make his own adapter. He did a very nice kon, and I think this is the way to go.



I've wanted to put a disk brake on a bike that had v-brakes.I bought a commercial bracket for motorized bicyle conversioms, a big chunk of aluminun. but the caliper went under the wheel, and it took 30 minutes to remove the wheel, because the axle went thru it. Eventually, I hacked it so the caliper went on top and I could remove the wheel. I could have started anew with some metal stock, but the holes for the caliper were correct with respect to the axle, so I re-used the piece. Looks like crap, but it is solid. and I can remove the wheel while leaving the brakes in place. The two arrows show the screws that attach my caliper U-bracket, I also have a front strut to offset the side load on the two screws that actually hold the bracket to the frame. The bracket is 3/16" aluminum.




I have a cruiser bike that I plan to add a disk over the winter. I'm going to try it with this adapter. I probably won't use the plate with the thru-hole though. The bike is FWD, so a skewer thru the thru-hole is OK, but I might rig a custom plate. It depends on hole the adapter lines up with the screw holes on the frame.

 

[docw009]

Adapter is in. Someone did a nice job with the CNC machine. If they just made the black piece without the u-shaped cutout, I could cut it it for a nice custome fit.

I haven't matched it to the frame yet, but hope I can find some material on the drop outs to attch it without the silver piece,