I need a brake

Bucket Residence · Mar 21, 2019

I recently purchased a new motor (hub) replacing my old, weak 250 w unit. The previous motor was using a drum brake which cannot be fitted onto the new. I noticed how many bikes sold today come equipped with disc brakes now - great - I thought - my new rim actually supports disc brakes. However, I'm now unsure if the frame does. It has holes, three of them, and I'm lost.

- Would a disc brake work for me? (see pic 2 of the fitting)

- Are there other types of brakes that could be fitted somehow? I don't see how rim brakes could fit anywhere.

- Are there other solutions? Like the adapter plate(?) pictured here: https://www.bikeman.com/bicycle-rep...8-51mm-international-standard-74mm-post-mount

Detailed pictures of the bike:
https://imgur.com/JUWfGHz

The thing is this bike is soon to cause marriage failure if not fixed, since it's taking up a large portion of the living room and has been doing so for the past months. Also promised the missus she would get to ride it once it was done. Not gonna happen without at least some sort of brake mechanism, the new motor is a 2 kw beast.

Any help is greatly appreciated!

amberwolf · Mar 21, 2019

Bucket Residence said:
I noticed how many bikes sold today come equipped with disc brakes now - great - I thought - my new rim actually supports disc brakes.

Rims don't have anything to do with whether a wheel (or bike) supports disc brakes. (they *do* have to be the right kind for *rim* brakes to work properly, however).

However, I'm now unsure if the frame does. It has holes, three of them, and I'm lost.

- Would a disc brake work for me? (see pic 2 of the fitting)

The image is not visible to me.
If you attach the image to the post using the attachments tab, everyone that can see the post can see the image.

Disc brake tabs will look like the stuff in various images here:
https://www.google.com/search?q=disc+brake+tabs&newwindow=1&client=firefox-b-1&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiNp_CGx5ThAhXHHjQIHe1OClgQ_AUIDigB&biw=1229&bih=679&dpr=1.5

There are places that sell tabs (some pictured in that search) you can weld to your frame, depending on your skills, equipment, and frame.

I don't see how rim brakes could fit anywhere.

Does your frame have brake bosses for rim brakes? If not, there are U-shaped brackets that can clamp onto the frame (kinda like the arches on suspension forks with rim brakes) to add those bosses.

- Are there other solutions? Like the adapter plate(?) pictured here: https://www.bikeman.com/bicycle-rep...8-51mm-international-standard-74mm-post-mount

I don't see any adapters on there, other than the plate that's really part of the frame / bike in the top left, with the green frame.

Not gonna happen without at least some sort of brake mechanism, the new motor is a 2 kw beast.

What about the brakes on your other wheel? Based on the little information provided (other than the images I can't see) I would guess it is a rear motor, so your front brakes should still be functional, and they are your primary brakes anyway.

Additionally, if the new motor is a DD hubmotor, then you can use regen and/or EABS braking as well, if your controller supports it. (some do, some don't. )

Do you also have torque arms on each axle end? If not, I would strongly recommend them.

BTW, is that pronounced, "bucket" or "bouquet"?

If you don't have any yet, you could probably make torque plates that also have disc mount tabs built into them. IIRC, it's been done here on ES before, and probably elsewhere, though a 30-second search didn't find the posts.

E-HP · Mar 21, 2019

I don't see an easy way to add mounts or posts to your frame. If it were steel, you might be able to braze on some mounts, but I'm guessing your frame is aluminum, since it's folder. Maybe a marriage counselor is in your future.

markz · Mar 21, 2019

Wheel Disc Brake Bracket Bike Frame Adapter Mounting
https://www.ebay.com/sch/i.html?LH_CAds=&_ex_kw=&_fpos=&_fspt=1&_mPrRngCbx=1&_nkw=bicycle+disc+brake+adapter&_sacat=&_sadis=&_sop=12&_udhi=&_udlo=&_fosrp=1

E-HP · Mar 21, 2019

markz said:
Wheel Disc Brake Bracket Bike Frame Adapter Mounting
https://www.ebay.com/sch/i.html?LH_CAds=&_ex_kw=&_fpos=&_fspt=1&_mPrRngCbx=1&_nkw=bicycle+disc+brake+adapter&_sacat=&_sadis=&_sop=12&_udhi=&_udlo=&_fosrp=1

The horizontal dropout may be problematic with any of the available adapters. There's a lot going on around the rear dropout, especially with that rack/fender post.

d8veh · Mar 22, 2019

That motor will give you less power than your old one unless you changed both the battery and the controller at the same time. A better solution would have been to keep your old motor and upgrade to a 48v battery and 20 amp controller, assuming that you have/had 36V.

Can you explain exactly what you had before and what you changed so that we can give the correct advice?

MadRhino · Mar 22, 2019

The rear brake is not much of a problem. Build good torque plates to secure the motor, then use regen for rear braking. On the front, use the best brake you can afford. 90% of your braking efficiency is from the front.

I agree that your new motor will need more power, and you might have to go bigger/better battery and controller to feed it.

Ps. If a woman wants divorce because of a bike, it is usually because she feels neglected. Be a responsible rider. Each of your mounts deserves its even share of your riding time.

Bucket Residence · Mar 22, 2019

Oh, looks like the I couldn't upload the picture directly. They are uploaded to imgur:
https://imgur.com/JUWfGHz

I like the notion of utilizing regenerative breaking. My controller is programmable and in theory it should work.

The old setup consisted of a 250 w motor coupled with a 36 v battery, 15ish ah. The old battery will be replaced with something more powerful soon. The brake looks identical to this one:

Will update once I get home.

Chalo · Mar 22, 2019

Bucket Residence said:
Oh, looks like the I couldn't upload the picture directly. They are uploaded to imgur:
https://imgur.com/JUWfGHz

That's a band brake, which is a kind of drum brake that doesn't work very well.

When I retrofitted a formerly electric bike much like yours, I mounted a BMX caliper brake underneath, on the kickstand plate. It's not a very strong brake, but it's at least as good as the band brake that was originally used. The bike has a good strong linear-pull brake in front.

If the bike needed to have a kickstand (which it doesn't), I could use a rear axle mounted stand.

Bucket Residence · Mar 22, 2019

amberwolf said:
Long text

Click to expand...

https://imgur.com/a/Ue2KWKx

The rear of the bike lacks brake bosses. It only has them on the front. I googled "brake bosses clamp" and I got a few relevant results. However they seem hard to find. But still, It seems like a viable option since I'm fairly convinced a disc brake won't fit and welding is out of the question.

Oh, yes, I was referring to the green bike pictured there. I thought it was some sort of adapter plate.

Btw, It's Bouquet! B-U-C-K-E-T!

@Chalo
Great idea, however that part is angled wrong on my bike, facing the tire.

donn · Mar 22, 2019

Chalo said:
When I retrofitted a formerly electric bike much like yours, I mounted a BMX caliper brake underneath, on the kickstand plate. It's not a very strong brake, but it's at least as good as the band brake that was originally used.

My old recumbent came with a "Pitbull" cam operated caliper in that location, I gather also a BMX item. And now sadly a collector item, they're real good brakes.

amberwolf · Mar 22, 2019

Bucket Residence said:
https://imgur.com/a/Ue2KWKx

Can't see that site.

If you upload your images directly to the post, using the attachment tab, then anyone that can see the post can see the images.

The rear of the bike lacks brake bosses. It only has them on the front.

THen you already have them on the important wheel.

You can just use regen braking on the rear (assuming your controller supports it), and that's likely quite sufficient for the rear, without mechanicals.

Otherwise, one of the clamp-on boss brackets is your best bet, as long as your rim supports rim brakes. (not all of them do)

Oh, yes, I was referring to the green bike pictured there. I thought it was some sort of adapter plate.

YOu could make one out of some thick enough metal, with a hacksaw and a file and a fair bit of time.

Btw, It's Bouquet! B-U-C-K-E-T!

Hopefully you'll have a bit better mechanical luck than they usually did.

d8veh · Mar 23, 2019

I meant for you to show us the bike and electrics, not the brake. A new battery isn't enough. You need a controller that can supply over 30 amps and a battery capable of providing what ever current your controller allows. It's the controller that determines how much power you get, and the other components need to be able to deal with it.

You need to think about where you install the battery too. It can make your bike unrideable if you put it on a rack. You'll need a big expensive battery if you want to go any more than 10 miles.

dogman dan · Mar 23, 2019

Your bike looks like steel, meaning welding a disk mount to the frame should be fairly simple. Easy if you can borrow a wire feed welder, or know somebody who could weld for you.

Some of the build thread links below show how you can fabricate and add disc mounts. just a matter of tacking a fairly thick steel plate to the frame, then by hit and miss, locate a good place to drill two holes. to mount the disc caliper, and what might be needed for spacer washers to line it up. The steel will need to be perfectly parallel with the disk, which can be done with a spacer block and clamping the steel plate to the actual disc on the wheel, then tack welding the steel. Then remove the wheel and finish welding.

Look at pictures of bikes with a rear disk brake, to get an idea where this plate needs to weld on, and how big it needs to be. Once its on the bike, excess steel can be cut away for a less crude look.

IMO, this would be easier than adding bosses for rim brakes.

E-HP · Mar 23, 2019

dogman dan said:
Your bike looks like steel, meaning welding a disk mount to the frame should be fairly simple. Easy if you can borrow a wire feed welder, or know somebody who could weld for you.

Sharp eye. I had assumed that it was aluminum because it's a folder, but this looks like a very similar bike and it's listed as steel. Getting a clearer shot of the dropout, it look like bosses can be added, maybe even between the seat stay/chain stay angle. Now I'm more interested, since I'm planning on getting a 20" folding e-bike and similarly converting to a big direct drive (and battery and controller to match); but the one I'm looking at already has discs.

https://journeybikes.com/products/nakto-fashion-20-folding-electric-bicycle?variant=17178354155609&utm_medium=cpc&utm_source=google&utm_campaign=Google%20Shopping&gclid=EAIaIQobChMIoLeIwbiY4QIVph6tBh2XYQSfEAQYAyABEgJ_fvD_BwE#description

Bucket Residence · Mar 23, 2019

d8veh said:
I meant for you to show us the bike and electrics, not the brake. A new battery isn't enough. You need a controller that can supply over 30 amps and a battery capable of providing what ever current your controller allows. It's the controller that determines how much power you get, and the other components need to be able to deal with it.

You need to think about where you install the battery too. It can make your bike unrideable if you put it on a rack. You'll need a big expensive battery if you want to go any more than 10 miles.

I'm not worried by that, I have ordered a controller with variable voltage, 36-72v and it can handle tons of power. See Luna Cycles programmable controller with Bluetooth. Atm it's stuck in customs :x I'll go with a Silverfish style battery like the one that I have right now, most likely 48v and at least 20ah.

Quick update: I ordered the "Wheel Disc Brake Bracket Bike Frame Adapter Mounting" recommended to me by Markz. I only spent about 4 USD on that part. In case that doesn't work out I'll go with a clamp on V-brake. My controller should be able to handle regen braking aswell.

Anyway, thanks to all of you! I'll update once everything is in working order.

dogman dan · Mar 24, 2019

If you enable regen, then you will find regen easily slows you to a speed you can apply only front brake safely.

Regen trick, use a horn button or other thumb push button on the left side to start the regen. Gives you more control than just the brake handle. Easy to get disk and regen at the same time, and very nice to get regen only when you want it.

donn · Mar 24, 2019

Isn't the slack before brake pad contact enough, to give you regen only braking? That's how it feels to me. Of course it wouldn't work if I had the brakes adjusted real tight.

MadRhino · Mar 24, 2019

Your brake need to clear and let the wheel spin without any rubbing. That is the basics of brake tuning.

markz · Mar 24, 2019

I agree with the welding, you can rent welders from home improvement stores for an hourly rate. I wouldn't go mig, but arc because then you just buy a 10 pack of rod. Mig you'd have to buy a whole spool which you'd never use.

Ask your friends if they have welders, or if anyone they know has a welder.

Ask a welding fabrication place or a machine shop if they can weld it for you.

Look for a "Do It Yourself" type car repair place. Like here in Calgary, there is a place called U-Wrench.
http://www.u-wrench.ca/default.htm

Look at the online classifieds for people willing to do some work that have a welder.
Maybe there is a racing team in your neighborhood, ask them.
Maybe there is a mobile welder in your neighborhood, ask them.

The Ultimate, and not so legit way would be to find a store with a relaxed return policy, and buy an arc welder, I would buy different clamps and cover the machine and cables up. Thats a big IF I were to do it.

Another option is to buy a used welder, use it, learn a bit, then sell it.

donn · Mar 24, 2019

I think the bracket is a much better way to go, but just curious about all this arc-welding - is that how builders do it these days, or is there still brass or silver brazing?

E-HP · Mar 27, 2019

Bucket Residence said:
Quick update: I ordered the "Wheel Disc Brake Bracket Bike Frame Adapter Mounting" recommended to me by Markz. I only spent about 4 USD on that part. In case that doesn't work out I'll go with a clamp on V-brake. My controller should be able to handle regen braking aswell.

I tried using one of those. You have to be really lucky to have the slot fit on the axle, since the motor axle is a larger diameter so it will only fit with the slot aligned to the dropout slot. Also, for your own safety, be really careful testing it before using it at speed:

https://endless-sphere.com/forums/viewtopic.php?f=3&t=67021&start=25#p1053740

I need a brake

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