Analysis on the Noise for the Different Gearboxes of the Heavy Truck

Table 2

The speed-ratio of the three gearboxes.

Speed-ratio	3-speed	4-speed	5-speed	6-speed	7-speed	8-speed	9-speed
Types I and III	7.31	5.71	4.46	3.48	2.71	2.11	1.64
Type II	9.39	7.33	5.73	4.46	3.48	2.71	2.10