Whats the significance of a mountain bike being a 29'er? What bike should i buy for trails?

Most people that try 29'ers prefer them to 26'ers. The main advantage of easily rolling over obstacles seems to more than offset the disadvantages of slower handling and more weight. Your best bet would be to find a shop (or a friend) to let you try one on the type of terrain you ride on. Try http://www.redlinebicycles.com for some very respectable 29'ers at reasonable prices. One caveat: if you are shorter than about 5'6" you may have a tough time finding one in a small enough frame.

The wheels are 3" larger. It tends to roll over more terrain with less interruption. I'm not sure if these bikes are going to be a fad or not though. It's not like you can go just anywhere and get a tube or tire either. If you want disc brakes, stay away from mechanical units and go for the hydraulic ones. What you really need is a good suspension fork. The unit you have on that bike is pretty basic, more for taking on bike paths than the trail. I would definitely go for a mid level Marzocchi, Rock Shox, Manitou, or any Fox fork. That would make a huge difference.

not really that much,i have a trek 3900 too and recently got a 2007 cannondale rush 5 for $1500.it was well worth ir,i dont know what ur price range is but i would highly reccomend canondale maybe a 2008 rush 5 or 2009 rush 6,those are both in the $1600 price range. if you can find one with a lefty for that price i would definatly get it unless it has mechanical brakes,then get one with a fox fork because it will have hydraulic brakes.if you can find a prophet with a lefty even better http://www.cannondale.com/bikes/09/cusa/model-9VM6.html http://www.cannondale.com/bikes/08/cusa/model-8VM5Z.html if you want to upgrade your bike instead(which is what i was going to do,but i wanted a full suspention) i would reccomed geting a fox TALAS fork,shimano XTR dual control shifters,shimano LX brake calipers, Shimano XT rear derailer, shimano LX front derailer, an FSA crank, shimano XT cassete and chain, michlin mountain X-Trem tires( the red ones), i would reccomend using 8 inch rotors for the brakes, and now that im thinking about it i dont think you could put disk brakes in the rear(thats how it was on older top of the line bikes, v-brakes in the rear and disks up front) but thats not a big deal because thay makes XTR dual control levers for v-brakes also Good luck with whatever you do

I would steer away from anything besides either a 700 mm or a 26 inch wheel. You will have a hard time finding tubes and tires. My mountain bike just sits in the garage, I ride my hybrid road bike (mountain bike geometry, road wheels/tires.)

Avid mechanical Disc brake BB7 -$49.95 -Cambriabike.com SRAM Juicy 5 - $94.98 ( they also sell juicy 7 )- blueskycycling.com Check the EMD9 (Niner),Ventana El Rey and Moots XZ 29er at Bikebling.com too!

I was confused when I first heard about 29'er tyres and wheels. However I soon found out that they seem to be 700 wheels with off-road tyres. Just like my cyclocross bike.