Singlespeed & Fixed Gear - Grindage

My guess is this is rather simple problem and I'm about to be made the fool, but here's what's going on:

Saturday night I felt a little grinding in one spot of my rotation (same small spot every time). Sunday put it on the stand and I pulled everything apart, cleaned, and regressed as I watched my Falcons fight to no avail against the Eagles (congrats Philly, ya'll best beat New England!). When I first put it on the stand and turned the cranks I was thinking the bearings of my BB were shot. However, one, and only one, of my chainring bolts was very loose. Fixed that.

Sunday night and yesterday (Monday) everything seemed fine and like vegan butter. This morning I checked my chain tension and felt it a bit too slack. I didn't notice it being loose yesterday and trackstands were no problem. Regardless, a bit into the ride to work I started to notice a slight grinding in a small spot of the rotation. I think it is in a slightly different spot then it was the other night. Any thoughts?

P.S.
The chain is only 2 months old, give or take 2 weeks.

hmmm...did you add tension to the chain AND THEN feel the grind? One thing I think mentioned a while back "re: chain tension" was the back pedal in the stand to check for the 'tight spot' - this may be the problem as over time, too tight a chain will cause undue wear.
Unless I am currently wasted, again

Yes, the added tension brought back the grind. There is absolutely a correlation, but I’m not sure if there is a direct cause and effect here.

It's your chainwheel being out of round or not properly centered on your spider. Sheldon has info on recentering your ring.

bingo! BT to the rescue

I tell ya, it ain't easy being this kind of obnoxious know-it-all. You gotta train and compete and even then only a tiny percentage ever go on to excellence.

Thanks dude.

God I love this place.

It took me a little while to find it, but here it is:
http://www.sheldonbrown.com/fixed.html#tension

if that doesn't fix it, I had the same sort of trouble and eventually found that one of my chainring bolts wasn't fully engaging with itself and therefore was never really tight enough. got a new bolt and it was fixed.
Then I noticed another creaking sound which happened on every other pedal stroke. I took the drivetrain apart again and found nothing. After two weeks of agonizing, I finally realized that it was the links from the NY Chain around my waist rubbing together. I want my new mini-u from kraptonite...like now.

tim

if that doesn't fix it, I had the same sort of trouble and eventually found that one of my chainring bolts wasn't fully engaging with itself and therefore was never really tight enough. got a new bolt and it was fixed.
Then I noticed another creaking sound which happened on every other pedal stroke. I took the drivetrain apart again and found nothing. After two weeks of agonizing, I finally realized that it was the links from the NY Chain around my waist rubbing together. I want my new mini-u from kraptonite...like now.

tim

Haha, I had same experience with abus chain lock around my waist.