Depending on the number of teeth of gears and what chain, some go on very tight others are fairly loose! The sae chain will fit two diferent top sprokets! Assuming that the gears are the same number as your old and that you have the same number of pitch chain? Put the top gear just on the threads, then the chain on it, the bottom in the chain. Then line up the splines on the bottom and just start it, with the adjuster out or as loose as possible, lift the top gear and rotate the rotor til up can slide the sproket on! Then just push them both all the way and put your washers and nuts (or bolt) and hold the brake to tighten it! The adjuster should be tight, but there should be just a little play. Hand tighten the adjuster bolt and tighten the lock nut is what I do!