Disc brake adapter?

My bike has a disc brake caliper on the rear wheel but the motor did not come with an adapter to attach the rotor to. I've looked at some old threads here and all the sites these adapters were sourced out of are gone or out of stock... arrgg! I read that spacing can be an issue, so let me know what you think.

The rotor that was on my old wheel was 160mm, the 6 hole spacing was about 44-45mm diameter and middle threaded part that screws onto the hub motor is about 35mm diameter.

Anyone know of a place I can get an adapter from? I figure I might as well use what I've got rather than throw a v-brake on it, just need something to throw this rotor onto.

Here http://www.sjscycles.co.uk/dt-swiss...apter-for-140-mm-oln-98-td-prod29105/?geoc=au

theres a couple different kinds of 6bolt patterns, I am no expert but I found this out the hard way.

the 44mm is comon on most 1 piece hubs, usually higher end, I have confirmed this on a couple of my bikes and some hubs I have been eye balling.

the other one is the spin on which I have several of those hubs and agapters but all are 48mm bolt pattern, this I have confirmed on a cheapie spin on front hub adapter and a disk brake kit for a hub motor and an Izip geared hub, they are all 34mmx1 thread I think

http://www.ebay.com/itm/271471510890?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT this is what I found that puts the 2 together

now here is where it ghets tricky, asuming that you are reusing your old disks, this is fine, I ordered some 203mm thats how I figured it out, I had several older spin on adapters all 48mm, couple chinese kits 48mm too, the disks are 44mm they would fit on my mountain bike which have some higher end hubs, a Quando I had laying arround, but not on a cheap wallmart bike which has a stamped steel hub with a 48mm adaptor.

now I bought a couple hub disk brake kits I think they were only $30 came with disk, adaptor, caliper, and a torquearm kindof that the caliper would mount too, pretty cool stuff, even had a spacer washer, if you are happy with 160mm that is great, problem came when I tried to put the 203s on which were 44.

the spacing that is another issue, the adaptor will spin up really close to the motor the caliper wont fit, most spacer washers are 2mm at best you need 2-3 and bought separately they are another $10 ea on fleabay plus shipping, unless you can find some locally, I was going to use longer bolts to space it, still figuring this out myself

Thanks guys! I've been doing some more searching and believe I found one that will work that's quite cheap (will just take some time to get here, but I'm in no rush)-
http://www.aliexpress.com/wholesale?SearchText=disc+brake+rotor+adaptor+44mm&catId=0&initiative_id=SB_20140508085740

I'll have to start looking for spacers... doubt I can find something local that will shim out the adapter from the motor. What about shimming the rotor from the adapter with small washers? I should be able to get some bolts that are more than long enough so I'm not hanging by a thread (ha ha), I know you start loosing strength by doing this, hopefully it won't need more than 2 washers?

I did both. The washers will work fine, just a little fiddling keeping them in place while you insert the screws.

I'll post some pics here shortly of the Chinese kits I got, like I said if I were happy with 160mm rotors they would be fine, the 203s were 44mm, than afain if you already got all the other stuff on the bike already you might not need all that.

the other Idea I had about spacing them was to simply buy longer screws, they will protrude, through the adapter and space it to the rotor instead of using a hundred large washers and a few more small ones,

also keep in mind your dropouts and some axle clamps, the good thing about those kits the caliper mount can serve that purpose, pics coming up

The one from SJS cycles is one that Spinning magnets has used & I believe it is the common ISO PCD of 44mm, as he used it for his MAC mid motor conversion to line up the holes for drilling the cover. If you want to run 203mm rotors then I believe this is the one you need, but do a search of the forum you should find the threads to confirm this. This adapter is also a lot thicker than the other alloy adapters and so would space the disc out further, so a spacer may not be needed.

The adapters sold by Conhismotors, gng, etc I believe are 48mm PCD and will only run the discs they supply, normally 140mm or 160mm.

To space the disc out you can use spacer washers for a screw on freewheel. I think Glow Worm Bicycles had some in the for sale section, but any good bicycle shop should stock them or at least be able to order them in.
As this is a bottom bracket thread, you can also use lock rings from an old bottom bracket to space it out, probably get used ones for free from a bike shop trash bin...

I've subscribed, my bike is V-brakes and I'm happy enough with them but I'd like to try out a disk brake on the front. Out of interest are thee similar adapters for the rear brake?

I have several spin on adaptors, some ordered especially for the ebike hub, some from cheap stamped steel front wheels, some from BMX they all spin on the hub but the 6bolt pattern is 48mm, that would be great if I were happy with 160mm rotors, I have a few that would fit, I'd also have to go with a cheap spin on front hub to match too, problem is I ordered a couple 203s a while back and those are 44mm bolt pattern, I looked through my stuff, I have a higher end bike with the fancy aluminum 1piece hubs, a front wheel with a similar hub all those are 44mm, even a shimano on ebay seller confirmed is a 44mm, it looks to me like the higher end one piece hubs use the 44mm, and the spin ons are generally 48mm, few I found that put the 2 together so I guess at the end is all about what you are trying to do.



I screwed on one of the 160mm rotors no spacer and the caliper wont fit, I tried a few. those Chinese ebike kits I have come with a washer, not entirely sure if it is wide enough, my thought here was to get longer screws, they will protrude through the adapter and rest on the engine cover effectively spacing it and I can grind them to fit

Looks like you need about 2-4 mm of spacer in there

http://www.bicycledesigner.com/bike-parts/bicycle-brake/disc-brake-adapter---free-or-flip-flip-hub.html

I've used this one to make a 48h front disc hub from a BMX rear hub. It uses the International Standard 6-bolt pattern rather than the larger and incompatible Chinese one that pops up often in the e-bike world.

IS dimensions call for 10mm between the dropout inner face and the rotor mounting surface on the front, and I think 15mm on the rear.

I am still confused which one is the IS standard, the 44 or the 48, the Chinese ebike kits are 48mm bolt pattern, so are the wallmart cheap spin on hubs, and yes I did the 48h bmx into a 29er rim rear hub for front disk, if I remember correctly I had to remove the back nuts to go from 135mm to 100 but it worked, I have a plain bmx hub with sealed bearings on a 48h 29er for this build, may use the disc one later will see

They are BOTH standards. Like inches and mm, left hand drive cars and right hand drive cars, Front, Rear or mid drive electric bikes, petrol or diesel cars, ............

alsmith said:

They are BOTH standards. Like inches and mm, left hand drive cars and right hand drive cars, Front, Rear or mid drive electric bikes, petrol or diesel cars, ............

Click to expand...

^This!


But if you are asking what is the most common 6 bolt size, it's 44mm. That's the IS for a 6 bolt disc, shimano style.

cal3thousand said:

alsmith said:

They are BOTH standards. Like inches and mm, left hand drive cars and right hand drive cars, Front, Rear or mid drive electric bikes, petrol or diesel cars, ............

Click to expand...

^This!


But if you are asking what is the most common 6 bolt size, it's 44mm. That's the IS for a 6 bolt disc, shimano style.

Click to expand...

hence the 44mm/203mm upgraded rotors, thou honestly in my garage 48 is more common, most of my stuff is cheapos,

http://www.walmart.com/ip/Wheels-Manufacturing-Freewheel-Shims-2.0mm-Bag-20/31974898

came across it by chance

I need a new adapter like this to my motor, its probably this kind with smaller inner diameter (probably arround 34m) and i have a HS1 rotor that came with my avid bb7 calipers and i mean to use it. Unafortunatelly, the new rotor holes didnt fit the adapter in the motor, so i noticed there are those adpters made up for 44mm inner diameter discs, but i'm kinda newbie in bicycle mechanis, so will this 44mm adapter fit in my motor(its a 40v 1000w hut, looks like golden motor but i cant say sure)? Will this adpter also fit my hs1 rotor? Thanks =)

cant tell what you are working with but the thread appears to be the same standard freewheel spinon thread rergadless, 34.9xmm or 1 inch I saw in some descriptions, some fine thread of an odd dimension either way not sure who came up with it, but it seems to be the same, the 6bolt pattern is what appears to be different and most of the time it goes unmentioned, if I had to make a calculated guess after browsing several products, ISO standard is 44mm across, this is common on most decent quality bikes and up, where the 6 bolt is one piece cast part of the rotor, all the spin on adapters I have which include hub motor kits, factory electric bike with disk, cheap wallmart front disk spin on hub, all are 48mm, I ordered some 203mm rotors not being aware that there are 2 different patterns and they were 44mm, I will tend to say the 48 is the odd one, and good luck finding any larger or fancy rotors in that size, hence the odd spin on adapters that have a 44 mm pattern, looking at the ones I have its not a lot of room to give, I have yet to get one of those but there wont be much clearance or material between the freewheel thread and the 6bolt at 44, I TEND TO BELIEVE THE 48 MM PATTERN IS MORE SO SPECIFFIC TO THE SPIN ON KIND FOR THAT REASON

48mm pattern rotors are specific to trash-quality disc brakes. You might as well use rim brakes, even calipers, if that's your disc option. The other alternative is to use a trash-quality rotor with a decent disc caliper (and have to straighten the rotor often because it warps).

Chalo said:

48mm pattern rotors are specific to trash-quality disc brakes. You might as well use rim brakes, even calipers, if that's your disc option. The other alternative is to use a trash-quality rotor with a decent disc caliper (and have to straighten the rotor often because it warps).

Click to expand...

that is kindof what I gathered I have a few 48s and they are most off/on cheap bikes with cheap components, the higher end stuff seems to be 44

Making note