modifying kit sprocket for coaster brake hubs

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bairdco

bairdco

a guy who makes cool bikes
Aug 18, 2009
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living the dream in southern california
i built a bike awhile ago and took these pics of my simple method for making the kit sprocket fit a coaster brake hub without having to modify the dust cap or spend all day grinding away at it.

simple, easy, and self-explanatory...
 

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bairdco

bairdco

a guy who makes cool bikes
Aug 18, 2009
6,537
264
63
living the dream in southern california
what happened, is i don't care enough to make it perfect. it's a kit sprocket.

the hole's big enough to clear the hub, so it's easy to line up straight, and you can't tell the middle hole is off center once it's all mounted up on the bike.

it's a 5 minute fix. ten, if you line it up perfectly.
 
tooljunkie

tooljunkie

Member
Apr 4, 2012
663
5
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Manitoba,Canada
thats all it takes.maybe a smaller hole saw to fit original hole and start the pilot from that.
but if all it needs is close.good enough.
thanks for sharing.
 
2door

2door

Moderator
Staff member
Sep 15, 2008
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Littleton, Colorado
The center hole doesn't need to be perfectly centered. All you're worried about, or should be, is that the outside diameter, the sprocket teeth, are concentric with the hub. The center hole could be egg shaped as long as it clears the dust cap.

Thanks Baird.

Tom
 
Andyinchville1

Andyinchville1

Manufacturer/Dealer
Dec 26, 2007
502
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Scottsville, VA
HI,

Technically if it is egg shaped it is out of balance BUT since the off balance portion is so close to the axle center line for all practical purposes you would not be able to feel it.

(the further away from the axle center line you are the more difference being out of you would feel....example, if you attach a 3 OZ weight to sprocket close to the axle you probably would not feel much if anything BUT if you took that same 3 OZ weight and attached it to the rim of a 26" wheel you would probably definitely notice something was wrong).

Andrew
 
dracothered

dracothered

New Member
Jul 25, 2012
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Howell, MI.
bairdco said:
and, we're talking about a crappy, rubber mounted sprocket bolted through the spokes, and being driven by a vibrating chinese piece of junk motor.

"out of balance" pretty much describes the entire bike...:)
Click to expand...
Yea, but if you can limit the number of areas out of balance you can cut down on some of the vibration.
 
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