Disc brake conversion

Just wondering if a disc can be fitted to this type of hub . Are there adaptors available.

I'm not 100% sure from looking at your photo, but it looks like your hub has threads on the left side. If so, the answer is yes, you can get adapters for a disc rotor. Just google "threaded disc rotor adapter" and you'll find a bunch. Also, there are rotors with permanently attached threads, like this one available from Grintech: http://www.ebikes.ca/shop/electric-bicycle-parts/motor-parts/diskt-6in.html

It does have a thread on the left side . Thank you for the info .

Not that hub. The frame has a disc mount. The hub doesn't. Even if there's enough physical space for a disc mounting pattern, the lateral spacing will be wrong, and it's easier than you think to strip the threads of a disc adapter.

V-brakes can be stronger and more sensitive than disc brakes; they just have to be set up with some care and not composed of the cheapest possible components. I'd suggest stepping up your game with rim brakes rather than trying to impose disc brakes on a system that doesn't support them.

^^^^..if the frame has V brake mounting posts ?

It looks like there are some rusty threads on the left side, its hard to tell tho. If they are there alot of manufacturers make that adaptor. Golden motor and conhismotor are a few, keep in mind you may need special washers to line everthing up properly. I used a similar setup about 8 years ago on my gm48v1000w gen1 hub.

Hillhater said:

^^^^..if the frame has V brake mounting posts ?

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Given that the frame looks like a BSO, and the disc tab looks like it's never had anything mounted on it, I think it's a safe bet that it has cantilever brake studs-- probably equipped with lousy quality linear pull brakes already.

I have to agree with Chalo on this one. Unless you post additional info, I would default to stating that rim-brakes "at their best" are more than adequate for the rear wheel of the common ebay kits that achieve 28-MPH on flat land. I have heard that the Kool Stop pads with the "dual compound" have quite a good reputation, with a useful balance between wet-situation grip, and adequate length of life-cycle (half is soft, and half is hard, red/black)

Kool Stop has an e-bike specific pad compound that I've heard nothing but good things about (though I have not tried it myself). A set of those pads or Salmon compound pads, plus a $20 Shimano V-brake, plus a $5 booster, set up correctly (with lined housing, die-drawn stainless steel cable, and an appropriate lever) yields far more braking power than you can use on the rear wheel. And it will have good feel and proportional lever response.

I wouldn't even bother with a booster on a normal rigid framed bike, but I think the seat stays on the suspension BSO might allow more than normal flex at the brake pivots.

These?
https://www.amazon.com/Kool-Stop-Lightweight-Version-Electric/dp/B00D6016MM

Thanks for replies everyone . What I wanted to do was upgrade the hub and electrical components to a newer better bike , preferably with disc brakes . From what I`m reading here , my hub may not be able to support a disc ?

If the hub is threaded on the left, then it will support a disc with the correct threaded adapter.

Chalo is just pointing out that
1) the rotor may not end up in the correct spot to match the caliper on a standard frame since hub motor manufacturers often ignore established bike standards, and
2) disc brakes are not inherently better than rim brakes, so if you have the option of rim brakes, there isn't really any point in screwing around with trying to make disc brakes work.

Brute said:

Thanks for replies everyone . What I wanted to do was upgrade the hub and electrical components to a newer better bike , preferably with disc brakes . From what I`m reading here , my hub may not be able to support a disc ?

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I see. Yes, under limited conditions and with some careful setup, your hub can be fitted with a disc brake rotor, so it can be made to work with a disc brake only frame. You'll need a threaded disc rotor adapter to attach to your hub. Be sure to get the 44mm International Standard size and not the 48mm Hokey Chinese Bullshit size.

I can only relate that my experience with putting a six bolt disc brake rotor on a threaded adapter didn't work out well. It took a great deal of finagling to make the caliper line up over the rotor, and then after a relatively short period, the adapter's threads stripped, destroying the adapter and badly damaging the hub.

On the other hand, before that I had a very expensive full-floating rotor disc brake from the early days of bicycle disc brakes, and it was mounted on a threaded spider. It had all sorts of weirdness and issues-- for instance, it completely dispelled the myth that disc brakes work better in wet conditions-- but it worked relatively well for many years despite being mounted on a freewheel type thread.

If I remember correctly, International Standard bicycle disc brakes specify a rear rotor mounting surface exactly 15mm from the hub lockout face/inner dropout face. If your hub and a threaded six bolt adapter can be made to provide that amount of offset, then a disc brake caliper should be able to mount normally to engage the rotor.

spinningmagnets said:

I have to agree with Chalo on this one. Unless you post additional info, I would default to stating that rim-brakes "at their best" are more than adequate for the rear wheel of the common ebay kits that achieve 28-MPH on flat land. I have heard that the Kool Stop pads with the "dual compound" have quite a good reputation, with a useful balance between wet-situation grip, and adequate length of life-cycle (half is soft, and half is hard, red/black)

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Hmmm! OK , rim brakes might be adequate, but they can't hold a light to hydraulic disc brakes. It's not so much about the stoppling power, they just can't match the consistancy and reliabiliy of braking. Hydraulic disc brakes are more or less fit and forget. I've never even looked at mine in 4000 miles since I fitted them, and still the braking is the same as when I built the bike. I bought them as used ones from Ebay. I would never consider anything else. They don't cost much either. I just bought a new road-bike for exercise, and I went out of my way to find one with HDBs. I'm pleased I did as they're brilliant.

Cable disc brakes are a complete waste of time by comparison. I think they're worse than rim brakes.

Chalo said:

Not that hub. The frame has a disc mount. The hub doesn't. Even if there's enough physical space for a disc mounting pattern, the lateral spacing will be wrong, and it's easier than you think to strip the threads of a disc adapter.

V-brakes can be stronger and more sensitive than disc brakes; they just have to be set up with some care and not composed of the cheapest possible components. I'd suggest stepping up your game with rim brakes rather than trying to impose disc brakes on a system that doesn't support them.

Click to expand...

I second the other opinions as well. I was quite sure I was going to convert my 012 Marin ebike from the stock V-brakes to mechanical disc brakes. I'm running a 72V battery at 40 amps with a 9C rear hub. It will do 40mph on a flat service & the last thing I need are weak brakes.

My stock brakes worked very well but I wanted that extra degree of stopping power, especially in wet weather.
Well the other week I came across Kool Stop brake pads http://www.koolstop.com/ that appeared to have a few features over my stock pads. I decided to try them out while I was saving up the money for disc brakes.

That said, after 45 years of working on motorcycles, bicycles, cars & equipment there are very few cheaper, better or easier upgrades that I have done that have impressed me more than this one.
Not only can I make a panic stop or lock-up the rear wheel with just 2 fingers, the modulation & control of the brakes is as good or better than any motorcycle I have ever owned.

Front & rear brakes cost $22.00. They are directional & are marked left & right with an arrow showing direction.
I have crossed disc brakes off my list of upgrades.

Not sure if you were asking purely for the hub or for lack of braking power on your ride but...
A second hand suspension fork with disc brake mounts can be found on ebay fairly cheap.
2 birds with one stone if your running a rigid fork currently.
Potholes at 20+ mph are a bits less scary with a bit of suspension up front.