I have no idea what you mean by "gear bike", so the question can't be answered.
Pick a gear that gives you the right ratio, then go for it. No difference than from a single-speed bike.
The word mountain can be used as an adjective. You might have a mountain bike, or mountain gear, or you might hike a mountain pass or trail.
No one gear is all you need, go singlespeed :)
Well, a track bike is a bike dedicated for use on a velodrome. It has a fixed gear, no brakes, often a steel drop bar and some other features. But with a but of determination you can stick a fixed gear rear wheel in any kind of bike. The wouldn't make it a track bike, but would make it a fixie. If you want to be hard core in your fixie riding, the "purest" is of course to ride a track bike in traffic too.
An AM bike is basically a cross between a XC and a DH MTB. Usually full suspension and long enough travel to take some fairly serious drops and jumps, but still light enough and with a gear ratio and a ride position that'll make it somewhat useful on the flat and during climbs. An AM bike is the best bike if you want to ride to the top, and do a decent descent. An XC bike will climb far better, but would suffer on the way down. The DH bike would be a pain to climb with, but be the best for the run down.
A brake shows the car/bike down until it comes to a hult/stop. A gear changes the speed the engine works at depending on what type of road you are driving on and the speed limits. If you are asking about a bike then the gear's change the speed at which you pedal at, gear 7 on a bike makes you pedal slower but you have to push harder down on the pedals, however gear 1 on a bike makes you have to pedal faster and more genitally on the pedals, - both gears really work your muscles... so if you have a bike with gears up to 7 stay on 3 or 4! Gear box = what you use to change the gears on a car. Handle bar = what you use to change the gears on a bike.
Bike Magazines articles consist of news, pictures, and guides about mountain biking and mountain biking gear. One can also find this information on their website.
what is
One can buy mountain bike shoes anywhere athletic gear is sold, such as Dick's Sporting Goods and Sports Authority. One would also do well to check Erik's Bike Shop and Penn Cycle, as those are shops devoted to bicycling.
Sparring gear is universal.
The driver gear has the input torque, and the driven gear has the output torque.
First gear on a bicycle with external/derailer gears is with the chain on the smallest chainwheel(by the pedals) and the biggest sprocket(by the rear wheel).