Hey guys and gals, I just got my first fixed gear bike that I have a question about. I tried to search but couldn't find this particular issue. And I probably suck at searching...

Anyway, it's a Kilo TT Pro and it's brand new so I haven't changed anything. My question is, when I use back pressure to slow or stop there is a fairly quiet but audible chattering coming from the drivetrain. It sounds like it could be the chain but I don't know that. It doesn't make any weird noises when pedaling, just when slowing.. I have about 1" slack in the chain. Since it's my first fixed gear I'm not sure what's normal and what isn't. Any thoughts? Thank you all for reading.

Eliminate the variables. Try these, one at a time:
Take more slack out of the chain and see if that quiets it.
Check chainring bolts for tightness.
Check lockring for tightness.
Check rear hub adjustment.

Check. Will do. Thank you!

Also (or first), check the headset. Chattering while slowing sometimes indicates that the headset is loose, regardless of where the noise seems to originate. To check, lift the front end of the bike an inch or two and let it drop. If you hear the telltale chatter, the headset might need to be adjusted.

Thanks. I know what you mean about noises being ventriloquists. I had a squeak on my other bike that sounded for all the world like cranks or BB and it ended up being the seat post.

It could be just the chain interfacing with the cog when you back pedal. When I back pedal it makes a distinct sound that only happens when I back pedal. Straight cut teeth cog 1/8’’ chain bound to make some noise.

I think you're right. I've done the other checks mentioned above and it still does it. Thanks for your input.

Most likely to be something to do with the chain. Assuming it's neither too tight nor too loose, and the chain line is reasonably straight, nothing to worry about on a new bike. It may take a little while to bed in. You may want to check that the chain is well lubricated and there are no tight links. (A tight link can be loosened easily with a chain tool.)

However, if you feel any skipping of the chain, have a proper look at it.

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Thanks for the advice. No skipping or other weirdness going on that I can feel. Ill have another look at the chain to see if anything is out of order as well. I feel better about it now though. Thanks everyone.