Bicycle Girl

Bicycle suspensions are used primarily on mountain bicycles, but are also common on hybrid bicycles, and can even be found on some road bicycles, as they can help deal with problematic vibration. Suspension is especially important on recumbent bicycles, since while an upright bicycle rider can stand on the pedals to achieve some of the benefits of suspension, a recumbent rider cannot.
• Wheels and tires
The wheel axle fits into fork ends in the frame and forks. A pair of wheels may be called a wheelset, especially in the context of ready-built "off the shelf", performance-oriented wheels.
Tires vary enormously. Skinny 18 to 25 millimeters wide, road-racing tires may be completely smooth, or (slick). On the opposite extreme, off-road tires are 38 to 64 millimeters wide and usually have a deep tread for gripping in muddy conditions or metal studs for ice.