If you do want to go for an easy ride in the park you don’t 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 they’ve got to offer, then buy it or have look on the Internet and maybe you’ll find the same thing at a better price.

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 isn’t 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.