Mountain bike frames are known as the all round bike frame as they are designed to be ridden off road, but can also be used on road. All Mountain Bike frames are built to be strong and slightly heavier than other frames to provide stability whilst riding down harsh terrains. There are 3 main types of Mountain Bike frames available, each individually designed to suit the various styles of Mountain Bike riding.
Rigid & Hardtail Frame
The rigid frame does not have any built in suspension and is commonly used by beginner riders as they are less expensive and designed more for everyday riding. The hardtail bike frame is the same as the rigid frame, however front suspension forks are added to provide additional suspension. Rigid frames are best suited for on road and smooth dirt trails. Hardtail bike frames can be used for off and on road purposes and are also most commonly used for racing.
Dual suspension frames, also known as full suspension frames, have not been the ideal frame to choose in recent years, due to the lack of technology in the rear suspension. This has certainly changed and now dual suspension frames have become arguably the best frame for certain terrains. With other frames, riding over bumps has an effect on the speed. The additional rear suspension on dual suspension frames allows riders to absorb every bump whilst still maintaining top speed. The dual suspension frame is more expensive than others in its class and is best used for off road and downhill riding.
As with any bike the lighter it is the faster you can ride it. So while mountain bikes are generally heavier due to the fact that they need to have great structural integrity for increased versatility, conversely they need to save weight where possible. This is where frame materials become increasingly relevant. The most commonly used materials are:
More widely used because of its weight and strength benefits as well as its absorption of terrain shock (bumps, ditches, etc). Carbon is a versatile material meaning it can be shaped into almost any form which is great for reinforcing specific areas of a bike for increased stiffness and or absorption, very important in mountain bike terms. Unfortunately it is amongst the more expensive materials
For a long time been the most widely used material in bikes. Its benefits are its strength, ease to work with and relative inexpensiveness, however it is heavier than other materials making it less competitive in serious riding circles.
Have lower density and lower strength compared with steel frames but they do have a better strength to weight ratio, giving it a notable weight advantage over steel frames.