Saint BB and arms

[kjsayers]

I am wanting to order a Saint M815 BB and crank arms not chainring. My question is can I use any chainring as long as the space between the bolts are the same? Example will all 104mm chainrings fit arms that are 104mm?

[AndrwSwitch]

No. Never assume. The bike industry exists to make compatibility headaches. You're probably fine, however.

Where I've run into a problem is with some Shimano chainrings that have a lot of detailing on the spider-facing side of the ring and mismatched crank spider tabs.

I've not run into that problem with other brands' chainrings. Not that it's impossible, of course. But if you have a look at the spider-facing side of the ring and it's pretty flat around the bolt hole, you're probably fine. Shimano's rings sometimes have a pretty distinct thinner area around the bolt hole and pretty distinct step not too far away.