I'm looking at larger chainrings for my 2006 Alpine 550. I believe it has the Truvative 5D crankset and Powerspline bottom bracket.

The more I dig in, the more I'm finding that I will probably need to replace the entire crankset with a 5-spoke design and possibly the bottom bracket. Does that ring true?

If so, what size bottom bracket do I need?

Will road bike components fit on this frame?

The Truvative 5D cranks are officially sea anchors. If you are considering new cranks and would like larger chainrings check out the Shimano XT FC M771 K
http://bike.shimano.com/catalog/cycle/products/component.jsp?PRODUCT%3C%3Eprd_id=845524441788120&FOLDER%3C%3Efolder_id=2534374302053570&ASSORTMENT%3C%3East_id=1408474395181785&bmUID=1204983853058
The BB is included with the crankset and it is a lot lighter. The rings are 48-36-26, standard rings are 44-32-22.

Oh, and you can find these on sale or on Ebay at a lower cost because most mtb'rs want the smaller rings.....good luck