I have a Traitor Crusade singlespeed cyclocross bike. fun for long urban rides on mixed surfaces and gravel races. I have the stock 36/16 gearing, but the FSA Comet crankset (modular spider with 96mm asym BCD) is making it challenging to put a bigger ring on it. FSA and their silly proprietary stuff that is never in stock!

I would like to replace the crankset with something that is reliable and cheap, and will have easy-to-find 38-42 tooth rings. Shimano 24mm road cranks would be great, but I am considering other options. New cranksets for this kind of riding are an option are limited, so I am going to check out the used/ co-op market. what would you want in a cheap, old crankset for this kind of thing? square taper is probably fine. 10 speed Shimano 105? Octalink Ultegra 9 speed are probably cheap and easy to find. what else would be a solid performance oriented option that I can find used or pretty cheap? lightweight would be nice, but I am not a weight weenie.

SRAM S300's or Sugino RD2's. Both are solid 130 BCD cranks. If you pick up a new set of S300's beware that you may have to drill out the factory chainring bolts. When I got mine the chainring bolts were impossible to remove due to the green loctite SRAM uses at the factory. Other than that I've been really happy with them.

SRAM S300s look like a good option.

I think I am going to get some "old" modern ten-speed 105 cranks. 24mm spindle and all that.

since this is a singlespeed drivetrain and not a 1x, is there any reason I should not just use the 39t inner chainring instead of buying a singlespeed specific chainring? it's a standard road double, so I could remove the big ring, install some short chainring bolts, and keep the smaller 39t ring. to the best of my knowledge, the 39t on a double ring looks an awful lot like a SS ring.