The hybrid category is best described as a cross between a road bike
MTB's will have large diameter frames for durability. Most frames today are made of aluminum for light weight. Carbon frames are available on more expensive bikes. The tires will be wide, in some instances over 2 inches, with a low air pressure of about 40psi.
The geometry of an MTB varies given the style of riding it was designed for, but like the road bike the geometry will be designed for efficiency in mind given the bikes purpose. A downhill racer will be much different than a cross country model. Almost every type of MTB will have some form of suspension which will vary again due to the particular style of riding the bike is meant for.
The hybrid category is best described as a cross between a road bike and an MTB. Designed for general purpose all around riding it can perform well in both on road and off road conditions. But there has to be some compensation therefore the hybrid will not equal the performance levels of a road bike or an MTB.
