Made my own sprocket adapter

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mybike1

mybike1

New Member
Dec 21, 2011
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Michigan City, Indiana
Ok, I looked around and didn't like any of the current hub adapters for the rear sprocket... plus I was **** bent on using the original New departure hub that I have... So, I made my own. Here's how...
I machined a couple pieces 6" diameter. The piece on the left is going on the outside of the wheel and the sprocket will bolt to it... the piece on the right will clamp around the hub.

Here's the piece clamped around the hub...

Here I bolted a standard 130mm single speed / BMX chainring onto the other piece... I ended up re-bolting it onto the backside eventually to get a proper chain line
 
mybike1

mybike1

New Member
Dec 21, 2011
59
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Michigan City, Indiana
Then I made some spacers to sandwich between the two pieces...


And here it is all put together with the brake arm back in place...

And here it is on the bike... everything worked out great... runs straight and true and one step closer to gettin' er done :)
 
ocho ninja

ocho ninja

Member
Jan 14, 2012
564
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San Jose, CA
Cool! Just another innovative way of saving money.
And sprockets are cheap, just buy a different sized pedal bike sprocket with the same bcd.
 
Greg58

Greg58

Well-Known Member
May 1, 2011
5,353
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Newnan,Georgia
That's a good idea! I was wondering how many teeth are on that sprocket, it looks like it will have good hill climbing power.
 
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mybike1

mybike1

New Member
Dec 21, 2011
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Michigan City, Indiana
Greg58, I chose to use a 53t sprocket... it's pretty large. It's definately the largest one I plan on using. The nice thing about this set-up is the fact that I can quickly change chainrings without too much effort... and I'm gonna fabricate an adjustable position chain tensioner so I can use anything from my 53t down to... ummm... maybe a 39t...??? maybe... not sure yet... still workin' on it...lol :)
 
mybike1

mybike1

New Member
Dec 21, 2011
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Michigan City, Indiana
Just a quick update...
I finally got it all put together and running and have a few miles put on...16 to be exact.
Just wanted everyone know how this 53 rear sprocket is working out... it's pretty sweet!
It's such a low gear that I can actually take off from a dead stop pretty easily with out any pedal assist... although I'm only 5'6" 145lbs so, it's hauling a little less weight than your average guy.
I'm using an old stewart warner bicycle speedometer and she seems to be bouncing between 25 and 30 mph when the rpms get up there... but not screamin'.
The motor is still breaking in and I'm not pushing it very hard so I'm pretty happy with the top end so far.... probably wont go much over 30 with this gear, but it does accelerate nicely... pulls better than I expected :)
The sprocket adapter is awesome. No slipping, no problems...and just sent the prints and paper work out for the patent.
If anybody wants to use their original New Departure hub and cant find a good adapter, just let me know.
 
GearNut

GearNut

Active Member
Aug 19, 2009
5,104
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San Diego, Kaliforgnia
What an excellent idea and really nice craftsmanship making it.
I do hope that you can produce these if even on an as needed basis. There are plenty of folks who run New Departure hubs.
 
mybike1

mybike1

New Member
Dec 21, 2011
59
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Michigan City, Indiana
Wow Mr. Aleman, little grumpy?...lol.
Yes, I'm getting a patent for it...
I'm a mechanical engineer with my
tool & dye journeyman's
card... and I patent everything.
Why wouldn't I ???
Ok, this part isn't going to sell
a million units on home shopping network...
but if I can sell a couple, why not?
I've made quite a bit of extra cash with
my patents... and I'm pretty proud of that.
This part isn't for everyone. it's not
stylish, although I happen to like it, but if someone
needs one... I can help them out.
Now go take your medication :)
 
WightBoy

WightBoy

Member
Aug 30, 2012
271
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16
Michigan, USA
This looks like a pretty nice design! How thick is the piece that clamps around the hub? I see bolts going through the inside piece too making this NOT a rag joint but a more versatile sprocket adapter similar to the pirate cycles one.
 
2door

2door

Moderator
Staff member
Sep 15, 2008
16,302
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Littleton, Colorado
The concept is exactly the same as any clamp on style. It puts no more stress on the spokes that any of the well known types. It relys on the clamping action on the hub.

Look at the design again, Caleb, and I think you'll agree. Yes, there is the potential for spoke damage, as there is with any clamp on adapter or rag joint if excessive slippage occurs. But that's the idea. It's not supposed to slip. As long as there is sufficient surface contact area at the hub, it shouldn't.

Tom
 
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mybike1

mybike1

New Member
Dec 21, 2011
59
0
0
Michigan City, Indiana
Yeah, I'm glad you guys get it. WightBoy, the piece that clamps around the hub is .625" ... if I were to go any wider it would have hit the oiler in the center of the hub... if someone wanted to go thicker, they would have to notch out a spot for that... it's do-able... I just dont think it needs to be any wider... so far it's holding great! We all know that more clamping surface is better... but in this case I'm counting on the fact that I machined this part to be within .002" of the hub diameter... it's a solid precision piece that almost snapped around the hub... then you torque down the clamping bolts and it's rock solid.
 
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