The bolts that hold the crank arm on are 00 or 00mm and are regular right threaded. But you need a "crank arm puller" to take the crank arms off. Then the Bottom bracket (BB) can be disassembled. You will need some bottom bracket tools also. Any bike shop can sell you these tools. The left side of the BB, the non drive side, as you are sitting on the bike looking down, is normal right hand drive and this is the only side that needs to be removed when overhauling the BB. Hope this helps. 