3 peice cranks kinda describe themselves. If you ever taken your crank apart whick you should of you expeirence the annoying sliding the crank threw. The three peice have 3 parts. The main the is actually in the bike. And two arms. Three peice cranks are alot stronger. I am not not verty good about describing this sort of thing. I have a backtrail x3 with the 3 peice crank. The crank on this bike is the cheapest that haro makes. Thats how it works two. It gets dirty in side easily becuas e of bad bearing. If you get the cheap crank you will end up spending the 30 dollars for sleaded bearings. Just save up longer to get a better one like 130 profile is pretty popular there 3 peices. Try to stay away for the large named companies. I learned this at when you go to rider owned company better products are usually in store. GO to hoffman, volume. Even though haro really popular right now becuase of there riders they have. There products are not the best. :thumbdn:
3-Piece cranks are great. I have the Specialized Strong Arm II 3-Piece cranks. Some cranks don't require a crank puller to remove them. Mine only needs a 8mm and 6mm allen key to remove. Some cranks that require a craNk puller come with it. SOME. The Specilaized Oversize Tubular Crankset comes with one.
MAKE SURE THE CRANKS ARE SEALED!
How much do you want to spend on them. They are ones called F.S.A Smack Daddys which are suppost to be preety dam good. F.S.A website is www.fullspeedahead.com and specilalized is www.specialized.com
Hope this helps!