i have an aluminum frame & carbon fork w/ headset from performance.
i recently purchased 09 tiagra shifters and have a good pair of alex wheels.
i just got my order of shimano 105 FC 5502 crankset (53/39).
i know that i have to use an octalink BB. is there a specific size that will fit the crankset and my frame?
You need to measure the OD of the Bottom Bracket shell This will give you the width of the BB. From that point you can figure the length of the BB spindle. Just as a WAG I think that you can use either a 68 or 73 bb with a spindle length of some where around 117.