6 bolt freewheel adapter

[Mainer]

Hi All,

I'm new here. I hope this is the right forum to ask this question.

Has anyone out there heard of this? A adapter that would allow mounting a reverse BMX freewheel (also called Lefty or Southpaw) to an ISO 6 bolt hub? I'm trying to drive the left side of a Nuvinci hub with a geared motor. No need to run a disc brake in conjunction with the freewheel. Just to be clear, the threading would be standard 1.37 x 24 (or the smaller metric 30.0 x 1.0) but left hand threaded...

Any help would be appreciated.

Best,

Davis

 

[pbeggs]

ive seen one ,.. it was made by a guy with his own machine shop,...

what are you useing for an engine and the rest of the drive train?

engine type 2 stroke 4 stroke happytime?(chinese 2 stroke)

reduction gearing?

for most of the setups we run need a 36-44 tooth sproket when driving that side of the hub,.. (when running a happytime)

we are very willing to help find a solution to any problem but we need info.

 

[Cavi Mike]

Never heard of a left-hand version but Bicycle Designer has the right-hand style.

http://www.bicycledesigner.com/bike-parts/disc-brake-conversion-kit-adapter.html

 

[pbeggs]

he has the 6 holes,.. needs to screw on the freewheel the opposite of that part

 

[Cavi Mike]

Ahh, I read it wrong. That would stick out so far it would hit the fork ends so obviously this isn't something that would ever go into mass-production. There are only a few options here, the best of which are:

#1) Thread the hub. Obviously you'll need access to a lathe.

#2) Buy a hub with threads on both sides. Staton makes them:
http://www.staton-inc.com/store/pro...ge_Hub_Left_and_right_hand_threads-848-0.html

 

[BigBlue]

Mainer,

I believe you would run into space issues with a 135mm chainstay clearance in the back end with the Nuvinci and a freewheel.

Here's a link on endless-sphere.com that deals with that specific issue. One recommendation would be attach a fixed sprocket to the ISO 6 hole disc hub and run a freewheel on a jackshaft or the engine, depending upon the setup you have. Ooops - see that you originally stated a geared motor. I assume an electric motor.

http://endless-sphere.com/forums/viewtopic.php?f=28&t=18232

Another issue would be how are you going to power the Nuvinci?

Good Luck,

Chris
AKA: BigBlue

 

[loquin]

I posted a sketch of this some time ago, here. Don't know if anyone has ever built one.

For ease of manufacturing, you could probably thread a tube, then weld the threaded tube to a flat ring (which has the 6 disk brake holes drilled)

 

[BigBlue]

Lou,

I don't think an adapter would work with a chainstay width of 135mm. Per the endless-spere.com post, only 13mm is available between the Duvinci disc hub and the left chainstay. My Dicta freewheel body is 15.60mm in width. I am sure other Southpaw freewheels are similar in width. Even if you could get it to fit, remember chainstays are tapered and I am sure the sprocket would rub on the left chainstay. Most outer sprockets on 9 and 10 speed cassettes are usually 11 or 13 toothed. A 18 or 22 toothed sprocket is more than likey to rub on the chainstay. A possibility would be a tandem with a 140mm or 145mm chainstay width.

The Tophat would be a good alternative to mount a fixed sprocket to the Duvinci disc hub. You might still be able to have a disc brake. Again, if using a 135mm width chainstay, mount a frewheel to the motor or jackshaft.

On another note, I like your adapter. Might use it some time down the road. A possibility is to weld a bottom bracket cup to the adapter.

http://www.amazon.com/Pyramid-Botto...ZFSK/ref=sr_1_2?ie=UTF8&qid=1337033320&sr=8-2

Chris
AKA: BigBlue

 

[loquin]

...

On another note, I like your adapter. Might use it some time down the road. A possibility is to weld a bottom bracket cup to the adapter.

http://www.amazon.com/Pyramid-Botto...ZFSK/ref=sr_1_2?ie=UTF8&qid=1337033320&sr=8-2

Chris
AKA: BigBlue

I thought of that, Chris. I bought one (as the left cup has the 1-3/8-24 left-hand threads, I believe,) a while back.

I've ground off the bottom of the cup, and am about ready to weld it to a 'donut.' (in this case, I'm making a LH Freewheel adapter for a creative engineering sprocket mount.) But, that cup is HARD! With a CAPITAL 'H' !!! I ruined a bi-metal 1-1/8" hole saw on it already! And, after I couldn't drill it out, it made sense - it's a bearing cup, after all... I'm bright that way - AFTER I bang my head against the wall, I generally figure out that the wall is hard, too, LOL

Anyway, I've heated the cup up to a dull red, and let it cool. Hopefully, that, and the heat from the welding will soften it enough that I can drill out the center!