dr_bovine

I just replaced the drive train on my single speed that was on its last legs after a rough winter. This was the first time I've done this myself and things went relatively smoothly. However, once I had everything back together I started to turn the crank and noticed a grinding/brushing sound coming from the freewheel (Shimano SF-MX30, 16T). The noise became more obvious as it the wheel slowed down and it was clear that the noise was intermittent (about once per revolution of the wheel) rather than constant. If I let go of the crank would spin a bit, but not as if it were a fixed gear (my old freewheel started doing this towards the end of its life, which I figured was it getting filled with road gunk after a sloppy winter). The chain is definitely not too tight. If I lightly held the crank from turning I could feel some force on the crank about once per revolution of the wheel that coincided (not surprisingly) with the sound.

My question is: is this a defective part or is this normal and will go away once the lube works its way around all of the internal bits?

operator

Lube it and you're done. If it's worn out, replace it. Shimano freewheels are $20 on a bad day at the LBS.

dr_bovine

But the one that is making noise is *brand new*, which is the cause for my concern.

JohnDThompson 

Here's what I do to quiet my freewheels: If it's used/dirty, flush it with solvent and allow to drain (or use compressed air if available to blow the solvent out). Then carefully drip oil into the gap between the inner body and outer body, rotating the freewheel occasionally. Eventually the oil will start dripping out the other side and the ratcheting noise diminishes. If it's clean when it comes out, go on to the next step, otherwise keep flushing oil through it until it comes out clean. Then take a heavy waterproof grease, like Phil's Bicycle Grease or generic marine grease (much cheaper) and use your finger to work it into the gap between the inner and outer body on both sides, to seal the oil inside the freewheel. Use a clean rag to wipe off the excess grease and oil and install. Enjoy an almost silent freewheel for up to several weeks. Repeat as necessary.

Panthers007

As an aside - if one wants a really nice freewheel, at about twice the price of the $20 Shimano, look into IRD. They are sweet and very quiet running, and they shift sure and almost silently. Assuming all else is properly tuned.

dr_bovine

Let me rephrase the question: Given that is a new part, should it be making noise/sticking like this? If not, then should I consider it defective and try to exchange it for a new one?

I'm not trying to fix-up my old one, I've nursed that along as far as it will go and now the teeth are badly worn at this point so it needs replacing.

Panthers007

You should lubricate it fully first off. It sounds like the pawls inside it are bone-dry.

My question to you is: Did you get a new chain to go with the new freewheel? If not - do so. When you swap out a freewheel/cassette, a new chain is generally mandatory as the old one will have "stretched" to fit the worn dimensions of the old freewheel/cassette.

z415

Possibilities are defective parts, lack of lube, worn chain, or different sizes (3/32 v. 1/8). Not really sure about the last part - I've seen 1/8 fixed parts, but ss, not too sure. Haven't been ogling in LBSs for a while.