Chainring quality/tight loose chain
 

So i've done a lot of searching but there doesn't seem to be a ton of info on my particular case so don't flame too much. I've got the Origin 8 cranks with a 3/32 chainring and i've gone through and adjusted the chain tension in the tightest spot but i'm getting a nice decent tension to a real loose tension. So i'm wondering if the origin 8 chainring is just crap and not round at all? Would the sugino mess chainring be a good upgrade for me or are there better options out there (my cranks are 130bcd). Thanks

Anyone?

that's fairly normal, i believe.

That's normal. Even high end stuff might not give you a smaller variation between loose and tight. It's random.

My Dura ace track crank/chainring/bb/kmc x10sl + phil wood cog on phil wood hub has no detectable variation in chain tension as you spin it.

My Sugino messenger does the tight/loose thing you talk about. I just put it on. I'm not sure if it's the chainring, or the crank that's off kilter. That kind of stuff bugs the crap out of me. When I get home from vacation I'm going to pull the chainring off and do some precision measuring (kind of like how you true a rim) and see what's off.

Here's why it bothers me. The chain is either getting more tight, or more loose. On the "getting tighter" 180 degrees of rotation, the chain likes to vibrate and at certain slower speeds can be kind of annoying, but only because I'm super anal about that stuff. Most people I don't think, would notice.

I've seen that before. There isn't any play in the ring-to-crank arena, but maybe I'm just a noob! I'm sure it takes some real practice.

Normal. No worries about it.

Just had the same problem with a Sugino 75 crank with Track ZEN 49t chainring. My chainring was out of center with the crank. I loosened the chainring bolts, slowly snugged each one as I rotated the crank and then re-adjusted the chain tension and its perfectly symmetrical now. I didnt see any reason the chainring could be out of center since it fits the 14 bcd arms perfectly but just a fraction of a mm off throws the chainring out of center.

Tanks for the answers i'll be trying the sheldon brown method and let you'all know how it turned out

I have ridden with several crank and ring combos, and with some of them I have had significant tight and loose spots.

In a few cases I could minimize the tight and loose spots with Sheldon's method, and in other cases I couldn't.

I would think that the more expensive cranks, rings and cogs would have more uniform roundness and that this would allow a tighter chain with fewer loose spots.

It could be a bent BB spindle, but it's not likely.

Higher quality cranksets/chainrings normally don't have this(loose/tight) problem.