Spin on disc brake adapter question
 

I have one of those x-games bmx bikes with front/rear disc brakes. the wheels have spin on adapters for the disc brake rotors, but the rotor pattern is different from other rotors I have. I want to use the wheels on other projects.


I just found these


EKfan Bike Disc Brake Flange Tray Adapter Plate Screw Thread Locknut Switch


and wonder if I can just get the smaller size.


are there more than two rotor bolt pattern sizes? they're cheap enough that i'll probably get a few and just try them, but I've brought a few already. there wasn't a size choice stated when I got them before. I just got them thinking they'd work, but found out they didn't work either. they were the size of the one I had taken off.


thanks for any knowledge on it.

What do you mean smaller? you can always hire a custom machine shop to make things one off.
the 6 bolt pattern is used on most disc hubs.. Shimano's CenterLock spline a recent exception..

threaded hubs with the thread on the left side are a common thing in older tandems.
its RH BSC thread like a freewheel, but because its on the left and the force applied is tightening due to braking.

there are threaded to 6 bolt adapters for tandems rear hubs, as a result.




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that's what I thought, 'til I started playing with this bike. it's actually the second time I've come across this problem, but I'd really like to find a solution this time. if you look at the ebay add, there are at least two patterns, I went ahead and ordered a few since they're cheap enough, but it would be good to know something for sure instead of just guessing, buying and hoping.

DT is one company, Swiss , That makes a Tandem adapter regular 6 bolt, 1.37 x 24tpi RH thread.
https://www.sjscycles.co.uk/componen...-mm-oln-98-td/

you can get double freewheel threaded rear hubs, both threaded ends same, so either end is driven or brake.

I have no idea about what they are measuring BB thread is between 34 & 36mm.

the BSC fractional metric equivalent is in between, I have not measured the disc brake bolt pattern standard bolt circle.

google found this one, maybe they can answer your question, it has 12 holes, http://www.leafmotor.com/shoponline/...product_id=183
they are in the electric motor biz it appears.

did not think 140 discs had a different bolt circle than 160 and upward. but that is what that is supposed to solve.

I only own 1 disc brake bike, & it has a Rohloff, it's own 4 bolt pattern, that is also a 4 bolt chainring pattern.





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4 bolt disc is an old MTB pattern, btw... probably not "custom" on your Rolhoff, just uses the old MTB discs, i'd bet.

I'm thinking it's the diameter of the bolt hole circle, like with car wheels. I ordered the smaller one because the bolt circle on the one that came on the bike is too big. hopefully there are only two patterns. i'll find out when I get them.

backtracking. I got the adapters yesterday. the pattern is a little smaller than what the x-games bike had and they fit what I guess is the more common rotor size I got aftermarket (the rotors that came on the x-games bike must be the odd size). I think when I have a few more spare bucks i'll grab a handfull more.

I believe to fit a single speed freewheel , with less teeth than is physically possible with a standard hub thread.

Smaller thread was created.. Now the huge stunt bike's axles are in a special hub , to get an even smaller cog.