Chain..Sometimes tight..sometimes loose?
 

What makes chain tension have tight and loose spots?

non-concentric chainrings or cogs

biopace.

Yeah, and cheaper old chainrings.

Ugly pants.

Nothing is perfectly round first off. Second, the way the chainring is bolted on is never perfect, so it will always be slightly off.

Crap.. I was hoping it wasnt the pants.

OK then knowing that, should i run the chain set at the tight spot or the loose spot?

a little bit looser than tight

bent chainring, bent crank spider or crank arm

Makes sense.....

adjust it at the tightest spot. rotate it all around, find the tightest spot, adjust it there.
whatever, look at the sheldon thing. hes a GODDAM genius.

sounds like a bent chainring. Spin it fast while upside down or on a sand and look at the chainring for a wobble.

Once you go slack, you'll never go back.

or...

If it's loose, it'll hasten your caboose.

Your right...Sheldon's site helped, its scarry, but it helped.