Some New Departure hubs will "snap" when going from drive to coast/brake. Something inside is binding, not letting everything in there do it's thing.
So a snapper has been a-buggin' since I built these wheels and put them on Back in Black. When the hub was overhauled NOS disc set, cone, driver, cog, and new bearings were installed. One thing I suspected might be causing the prob was the clutch sleeve sticking in the drive shoulder from the sticky grease. I didn't really think this would be the cause as I don't tend to over-grease, but as an unscientific test I put a little oil on it. This has improved the action on other hubs I've overhauled so thought it might help here.
Back into the bike and back on the road...shoot: still a-snappin'.
Into the stand with Back in Black, wheel off and into the axle vise, open the D up.
So what would impede motion and cause snapping? There are 3 things that move left and right in there: disc pack, brake clutch, and clutch sleeve. Since the clutch sleeve wasn't being caught by the shell or driver, and the clutch was moving freely on the disc support sleeve, there had to be a problem with the motion of the discs.
If the ears on the discs are misshapen they might not slide in the keyways nicely....NOS discs tho: flat, smooth, pristine ears.
So the only things left were the keyways in the hub. Wipe out the grease, get some cotton-swabs in there...
Eureka:
There were 2 bad spots in 2 keyways. I could see and feel them sticking up enough to cause binding.
File, sand, repeat, clean, reassemble.
Back into the bike, back on the road.
Several good stands on the pedals, throw foot back to coast: silence...beautiful.
So the cause of snapping on this D was damaged keyways. I suppose an axle bent enough to misalign the driver and clutch sleeve could cause a similar problem, but I suspect that if the axle was bent that far out the hub wouldn't work anyway.
Note: In a pic above you'll see an arrow pointing to a rough spot outside of the keyways. This was not in the path of the clutch sleeve, but I left it alone anyway to test the keyway fix.
So if you have a snapper, check the ears on the discs, and look for burrs in the keyways and on the disc support sleeve. File & sand them down, might just fix you up.
So a snapper has been a-buggin' since I built these wheels and put them on Back in Black. When the hub was overhauled NOS disc set, cone, driver, cog, and new bearings were installed. One thing I suspected might be causing the prob was the clutch sleeve sticking in the drive shoulder from the sticky grease. I didn't really think this would be the cause as I don't tend to over-grease, but as an unscientific test I put a little oil on it. This has improved the action on other hubs I've overhauled so thought it might help here.
Back into the bike and back on the road...shoot: still a-snappin'.
Into the stand with Back in Black, wheel off and into the axle vise, open the D up.
So what would impede motion and cause snapping? There are 3 things that move left and right in there: disc pack, brake clutch, and clutch sleeve. Since the clutch sleeve wasn't being caught by the shell or driver, and the clutch was moving freely on the disc support sleeve, there had to be a problem with the motion of the discs.
If the ears on the discs are misshapen they might not slide in the keyways nicely....NOS discs tho: flat, smooth, pristine ears.
So the only things left were the keyways in the hub. Wipe out the grease, get some cotton-swabs in there...
Eureka:
There were 2 bad spots in 2 keyways. I could see and feel them sticking up enough to cause binding.
File, sand, repeat, clean, reassemble.
Back into the bike, back on the road.
Several good stands on the pedals, throw foot back to coast: silence...beautiful.
So the cause of snapping on this D was damaged keyways. I suppose an axle bent enough to misalign the driver and clutch sleeve could cause a similar problem, but I suspect that if the axle was bent that far out the hub wouldn't work anyway.
Note: In a pic above you'll see an arrow pointing to a rough spot outside of the keyways. This was not in the path of the clutch sleeve, but I left it alone anyway to test the keyway fix.
So if you have a snapper, check the ears on the discs, and look for burrs in the keyways and on the disc support sleeve. File & sand them down, might just fix you up.
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