How to choose a mountain bike depends on what you are going to do with it, if all you want your new mountain bike for is going for a nice leisurely ride on the canal path or a ride in the woods with the dog, well you wont need a full suspension downhill machine with 4 inch travel on the forks and a fully articulated rear end with damping and rebound control.
+ Where to Start From.
If you do want to go for an easy ride in the park you dont need to spend too much, if you think you will do any off-road riding then big tread tires maybe all you need, but if you think you might try some rough stuff then you will need suspension. Gears will probably be Shimano, brakes must be V-brakes, but could be made by a few different manufacturers, all the rest of the MTB components will depend on how much you can spend. If you go to your local bike shop or big sports store and see what theyve got to offer, then buy it or have look on the Internet and maybe youll find the same thing at a better price.
+ The Next Step Up.
So maybe you want to be a bit more adventurous, more off-road, more forest tracks and dry boulder river beds, then youll need something a little lighter, with suspension forks. All this will cost you more money, but will be worth it for the extra enjoyment and adventure. With a better mountain bike it will have a sportier handling and because it is lighter, it will be easier to struggle up the hills before you come flying down the other side. The components will again be Shimano and the quality will depend on how much money you can spend. V-brakes and Rapid-fire gear shifters, along with Shimano chain set, bottom bracket and headset. Handle bars, stem and seat pin should be alloy and along with a comfortable saddle youll be set to take to the hills.
+ More Money, More Bike.
The next rung up on the mountain bike ladder would be good enough to race on. There are many to choose from, get on the net and surf the bike manufacturers sites and all the shop sites along with the magazines for juicy photos of the bikes. The top manufacturers in this price range, I would say are: - Trek, Giant, Specialized and Cannondale, these companies make the nicest frames with the best mountain bike parts available at the price, gears will be either Shimano or SRAM, brakes could be V-brakes or cable disc brakes, both are very good and light, most of the other MTB parts, of course will be Shimano and as usual get the best you can afford. There are many combinations of hubs and rims to make up your wheels; hubs from Shimano and rims form Mavic are the usual mix. Then you have to choose which suspension forks to put on you bike, you may not get a choice, depending on which bike you buy, the main ones are Suntour, Marzocchi, Manitou, Fox, RockShox and RST, buy any of these and you wont go far wrong.
+ Top Bikes. Top Money.
If you want what the professionals ride you will have to pay a lot of money a professional MTB. As with road bike at the top of the range, you can specify what you want to build up your dream bike. Top bikes frames to spend your money on could be Klien, Scott, Rocky Mountain, Gary Fisher, Santa Cruz and K2; these are some of the most sought after bike frames in the world and would be the envy of your friends. Probably the best forks to put on your frame would be RockShox SIDs these are light and do all the things you need with control of all functions, there are many other to also to consider, look at how much travel they have and the rebound and damping systems. Gears again will be either SRAM or Shimano Rapid fire, XT or XTR, more money could be spent on carbon or very light alloy cranks, the brakes should be hydraulic discs from Hayes, Pace or Magura or stick to the trusted V-bakes. Wheels from Shimano or Mavic or some fancy carbon wheels, but remember they will have to take a lot of punishment, so maybe better to go for reliability over light weight expense. Carbon handle bars, stem and seat pin and a light weight race saddle and Time or Shimano SPD clipless pedals, then your choice of tires will depend on what terrain and ground conditions you are going to ride on.
+ And Downhilling?
Downhill bikes are very different, more like a cross country motor bike, but without the engine, low center of gravity and a lot of travel on the suspension on the forks and the rear end, disc brakes, wide rims and fat tires, gears are only at the back as usually a single chain set is used. Unless your going to do a lot of downhill racing then there isnt much point in buying one as you have to get up the hill first before you can come down and as light weight is not an issue with downhill bikes, they are very heavy to get up hill with out the use of a tow rope or a ski lift.