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Old 05-16-21, 08:49 AM
Join Date: Jun 2009
Location: Too far from the beach in Wake County, NC
Posts: 31

Bikes: Nishiki Medalist

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Originally Posted by Andrew R Stewart View Post
Some freewheels, SunTour Perfects as example, can rock on their pawls with each turn or the wheel. Most all freewheels have some slight bearing preload slop (and this is a decades long known good thing). When the chain contact is not over the pawls (like when in the higher gears. smaller cogs) a sideways force is acting on the freewheel's outer portion (of the core). The outer core and it's mounted cogs can rock with the pawls acting as the pivots. A knock/knock that is not usually loud and seemingly inconsistent (due to cog/chain combos needed and pedal pressure amount being rather independent of each other a pattern can be hard to discern) can happen. Shift a gear or shift on the seat and the noise can go away. Another rider on your bike might not induce the noise.

Lubing the freewheel interion can change this as does a different one. Andy
Looks like Andrew is on to something. Replaced the bottom bracket bearings and the noise is unchanged. There are stretches when the bike is absolutely silent save for the noise of the tires on smooth pavement. Other times I hear a knocka-knocka sound that seems to be telegraphed through the frame. No real discernable pattern as Andrew noted.

I tried lubing the freewheel (Shimano 13-28, 7-spd) with some Tri-flo and I'd like to say that the sound is lessened, and it seemed that way for a few miles. Most of time, the sound is most noticeable when using the middle sprockets.

After the ride, I put the chain on the smallest sprocket and applied some sideways pressure on the 28, noticed a very tiny amount of side play, barely detectable.

Does anyone suggest that the freewheel is defective or just doing its thing? Should I try heavier oil or try to disassemble the freewheel and re-lube the bearings? The noise can be quite loud.
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