Originally Posted by
FBinNY
Par for the course. Only the most expensive cranksets are round and turn on center. All the rest are cams and the chain will tighten and loosen as they go around.
As noted above, SB offers some ideas on improving concentricity, which works on some, but not all cranksets. Otherwise live with it, but be sure to adjust chain tension (slack) so there's at lease vestigial slack at the tightest position. If not, you'll be back posting about hearing Rice Krispies in your drivetrain.
Pretty much. Higher price = more perfect round spin, among other things. There are always somethings a person can do on the user end, like proper tension and chain ring centering. Depends on what your "good enough" is.