The impact of unbalanced wheels and vehicle speed on driving comfort

The paper presents the test results of vibrational comfort of two passenger cars, in which a defined and a variable unbalance of a front wheel was set. The vehicles were in a good technical condition and belonged to the C-segment and D-segment. Each vehicle was equipped with steel wheel rims and tires of the same size (185/65 R15). The wheels were put into unbalance by installing additional weights of different mass inside steel wheel rims. The vibrations, recorded for various driving speeds, of the elements of suspension, steering, floor, and driver's seat (lower part) were first analysed in the time domain and then followed by spectroanalysis. The vibrational comfort was assessed by means of the r.m.s. coefficient. It was the basis to indicate that the vibrations of the seat and floor plates of the tested vehicles, induced by significant wheel unbalance, do not cause discomfort during the drive. On the other hand, discomfort is caused by vibrations of the steering wheel both in the C-segment and the D-segment vehicle. The summary of the paper presents the tests conclusions.