Although the tires fitted to the wheels will provide some form of cushioning during ground roll, it is also normal to add some form of suspension between the wheels and the main aircraft body. At its simplest, this will take the form of some compliance in the wheel struts, either in the form of a deliberately wound spring element or by relying on bending of the main strut in the form of a compliant beam subject to a tip load. The problem with such a simple approach is that very little energy dissipation can be achieved by using only the elastic behavior of the strut. To get better dynamics, it is necessary to add some form of shock absorber; this may take the form of a rubber compression element or be as complex as coil over gas strut of the form now commonly seen on off-road bicycles, although the more complex devices are again seldom warranted on lighter aircraft. Figure 7.3 shows a nose wheel and strut with integral suspension elements. Figure 7.4 shows a simple spring-based tail wheel suspension.