Ford 2003 Mustang Workshop Manual page 116

For a vibration concern, use the vehicle speed to determine tire/wheel frequency and rpm. Calculate
tire and wheel rpm and frequency by carrying out and following:
Measure the diameter of the tire.
Record the speed at which the vibration occurs.
Obtain the corresponding tire and wheel rpm and frequency from the Tire Speed and Frequency
Chart.
If the vehicle speed is not listed, divide the vehicle speed at which the vibration occurs by
16 km/h (10 mph). Multiply that number by 16 km/h (10 mph) tire rpm listed for that tire
diameter in the chart. Then divide that number by 60. For example: a 40 mph vibration
with 835 mm (33 in) tires. 40 ÷ 10 = 4. Multiply 4 by 105 = 420 rpm. Divide 420 rpm by 60
seconds = 7 Hz at 40 mph.
Tire Speed and Frequency Chart
Tire
Diameter Tire RPM/Hz
mm (inch) @ 16 km/h (10
483 (19)
508 (20)
533 (21)
560 (22)
585 (23)
610 (24)
635 (25)
660 (26)
685 (27)
710 (28)
735 (29)
760 (30)
785 (31)
810 (32)
835 (33)
864 (34)
Tire RPM/Hz
@ 80 km/h (50
mph)
182 910/15
173 865/14
165 825/14
158 790/13
151 755/13
145 725/12
139 695/12
134 670/11
129 645/11
124 620/10
119 595/10
115 575/10
111 555/9
108 540/9
105 525/9
102 510/8
Tire RPM/Hz
@ 97 km/h (60
mph)
1092/18
1038/17
990/16
948/16
906/15
870/14
834/14
804/13
774/13
744/12
714/12
690/11
666/11
648/11
630/10
612/10
Tire RPM/Hz
@ 113 km/h (70
mph)
1274/21
1211/20
1155/19
1106/18
1057/18
1015/17
973/16
938/16
903/15
868/14
833/14
805/13
777/13
756/13
735/12
714/12
mph)