So due to peer pressure I am going to buy my first mountain bike, well actually trade an extra road bike for one. There is a local guy who has a newer(09) Specialized Hardrock pro with an alivio groupset or an older(07) gary fisher pirahna with deore. If I understood him right the groupsets are for different purposes, utility vs. mountain? They both fit extremely well, but I was wanting some input. I would be using it mostly for commuting and some mountain biking in the winter. I just wanted to know which group would be better suited or if the alivio was actually substantially worse. They both come with the same disc brakes so. Any help would be greatly appreciated.
Assuming they both fit the same and are both in good condition, go with the Piranha. Piranha's a 9-speed, Hardrock is only an 8. Axel on the Piranha is marginally better than the Dart 3 on the HR...though not by much. Groupset is nicer on the Piranha too...Deore shifters and RD (Alivio up front), whereas the HR has an Alivio RD and really entry level stuff on the shifters and FD. FD I don't actually care about that much since you don't use it as often, but having decent shifters is a nice bonus. The HR actually has hydraulic discs, which is cool, but they're Tektro Aurigas and you'll probably be happier with the BB5's that come with the Piranha anyway.