No chainrings are perfectly circular, but the cheap ones - usually stamped from sheet material and not CNC'd - can be out quite a bit, this does not make any difference to your average geared drive train as there is slack in the chain, but in a fixed or single speed drive train you will have problems.
No chainrings are perfectly circular, but the cheap ones - usually stamped from sheet material and not CNC'd - can be out quite a bit, this does not make any difference to your average geared drive train as there is slack in the chain, but in a fixed or single speed drive train you will have problems.
Buy a good CNC'd ring like a TA specialties™.