Chainring compatibility I need to change my chainring(s) and am interested to know what the things to pay attention to are. The ones that are clear to me are:


the number of holes for the crank
bolt circle diameter
distance between the bolts


as somebody that has never done it, I'd think this would be enough, yet I have found some in a shop where the compatibility is explicitly stated to my cranks, but also some where the measurements are the same, and my cranks are not in the list of compatible ones. Is the list just incomplete or inaccurate, or are there also different factors to pay attention to?

For now I will buy some where the compatibility is explicitly stated, but would like to know more in general.
Unfortunately chainring compatibility can be a bit more complicated than number of bolts, BCD and pattern.

Higher end cranks such as Shimano Dura Ace or Ultegra have rings that are shaped to blend into the crank body. Those cranks are only compatible with the rings specifically made for them. 

Some cranks may also require rings where the mounting points are offset laterally from the plane of the circle of teeth.