gear won't fit around coaster brake arm

GoldenMotor.com

chad223

New Member
Sep 20, 2010
19
0
0
NC
Has anyone else had this problem? I'm at a loss of what to do aside from fabricating a different brake arm which I really don't feel like doing...
 

happycheapskate

New Member
Nov 26, 2009
1,989
3
0
Rockwall TX
A lot of coaster brakes have a dust cap under the brake arm, that rides on the outside of the hub. You can try this method. Remove the brake arm and see if the dust cap has a D shaped hole that mates with the axle cone nut. If so, remove the dust cap (finger removeable or use a pocketknife). See if the cog will slip over the hub where the dustcap was. If not quite, you can file or lathe the hole a little bigger to fit. The dust cap can be flattened or filed down on its lip, to compress against the cog. (grease!)

This has worked for me for over half a year! (using common single-speed or 6 speed chains. 415 doesn't fit. )
 

Gator Wrestler

New Member
Jan 22, 2009
124
0
0
Springfield LA
I have developed a method of enlarging the sprocket hole that is quick and accurate.
I use a power hand drill with a round file chucked into it. The sprocket hole is placed over the round file and using the other hand to hold another file (I use a curved one) the drill is run at a high speed. The sprocket is allowed to spin and the action of both files on opposing sides of the hole quickly enlarge the hole. Don't forget your safety glasses.

Tom
 

happycheapskate

New Member
Nov 26, 2009
1,989
3
0
Rockwall TX
That's great. You can get metal-grinding round bits or round files, round sanding-bits, etc for $10 or less usually. Most people have a drill already or can borrow one. cvlt1

I have developed a method of enlarging the sprocket hole that is quick and accurate.
I use a power hand drill with a round file chucked into it. The sprocket hole is placed over the round file and using the other hand to hold another file (I use a curved one) the drill is run at a high speed. The sprocket is allowed to spin and the action of both files on opposing sides of the hole quickly enlarge the hole. Don't forget your safety glasses.

Tom