Crankset to replace?
 

Hello,
I have a Giant Yukon ATB, and the big chainring is missing teeths. I do not see any bolts to remove the chainrings. Do I have to replace the whole crankset, with both crankarms?
If I do , what crankset shall I buy? Do I need to replace the BB as well?
I have square holes in the crankarms. Is there anything else to worry about?
I would like to buy the proper tools and to do this myself.

Any help will be appreciated.
Thank You.

If the chainrings are rivited you can't do anything about it. to replace the crankset you need a hex wrench and a crank puller.

As long as you get a square taper crankset you probably won't need a new bb too. Depends.

Those teeth are probably meant to be like that to ease shifting the chain between rings. If the teeth are missing at opposite sides of the ring, the chainring is OK.

How did your chainring happen to lose it's teeth? It might be a biopace chainring and if so some of the teeth look like someone ground them down- this is normal.