I've replaced my old chain and chain ring with a new 1/8 chain and 1/8 chainring - kept the old cog - also 1/8 and in good shape. (riding it fixed with a good chainline.)

I get a really loud grinding noise when cranking hard but nothing with soft pedaling.

I have had this before where it was a new chain and it only made the sound for the first ride or so then slowly went away.

This one seems more pronounced - and doesn't appear to be going away.

Tried: Lubing & re-lubing, re-adjusted the wheel in the drop-outs several times, etc...

it was really quiet before the new chain and ring.

Has anyone ever had this griding noise issue before? could it be just a matter of getting the chainring "ground" down to a perfect fit with the chain (the chainring was from eighthinch.com - cheaper than most - wondering if this is what a cheaper chainring does if it is not machined perfectly...

Thanks

There is too much wear in your cog. The only permanent solution is to replace it.

I have read in a number of places that as your ride your bike, your cog and chainring "ramp" as they get older. Basically each tooth side becomes steeper thus creating an uneven mountain shape for each tooth. However, you mentioned you replaced your chainring. With that being said, im guessing your cog may be old and thus only really "fit" with your old chainring and chain. If your cog is not worn, you may have just purchased a noisy chain. Wipperman makes a noisy chain from what I hear.

Sometimes the grinding sound can also be from dirt or sand on your chain. I gave mine a bath in WD-40 to degrease it and clean it off, then re-lubed it. It was 10x quieter after that.

Again, check the tooth shape of your cog and compare it to the shape of you new chainring. Good Luck

I'm pretty sure it is coming from the chain ring - not the cog. Could be wrong though - it's hard to tell because it doesn't grind when on a stand etc...just when cranking hard on it so i'm riding it when i hear it.

What kind of chainring is it?

i'll try replacing the cog and see if that makes a difference though - thanks.

agreed **if everything else is new***

its an eighthinch brand (www.eighthinch.com) - seems like a decent chainring - but is was cheaper than most.