ok i guess you have never installed a3 piece crank set before then?
well here goes, if the frame that you are installing them onto has had a 1 piece crank on it then you will need to remove the bearing cups that the old crank has used( just a couple of hits with a hammer and screwdriver should do it) once the old cups are out your ready to start preping the flights. in the set you will have got the spacer 2 sealed bearings/cups the axel 2 crank arms 2 allenkey wrenchs 1 chainwheel fixing bolt and some washers. what you need to do is to offre up the axel with the spacer with the 2 sealed bearing in situe up to your bottm bracket to get an accurate measurement for the spacer. once you have this measurement get an hacksaw and trim the spacer down to the correct size. your just about there once you have the spacer the correct size you can start fitting the sealed bearing theri is 2 ways to do this:
method 1) get a piece of wood place the first bearing over the bottom bracket and beat into place using the hammer and wood technique. place the axel, spacer and second bearing in place and beat again.
method 2) using a vice( much easier) slightly grease up the inside of the bearing cups and axel + spacer, place the whole thing insitue (can be a bit tricky), then start to turn the vice tightening and turning the frame so that the bottom brack goes in nice, straight and flush.
once you have the bottom bracket in place then it is just a case of putting on your chainwheel to the driveside crank arm sliding it into place and tigthning the pinchbolts to the axel. this done you can place the endbold on to the axel and tighten aswell. repeat for the non-driveside crank arm.
check that the crank arms arent going to hit the frame chainstays (if they are too close use the washers to pack it out) and that when you put the backwheel in, the chain alignment is straight.
Then your ready to roll.
long winded i know but i tried to be as thorough as possible.
