In the travelling speedometor of a wheel type excavator, the input shaft (31) of a speed governer (30) is mechanically connected to rotate with a main shaft of the speed change gear. The retractable shaft (34) of the governer (30) is connected to a push rod (41) of a reduction valve (40). The pressurized oil of a gear pump is supplied to a preliminary port (43) of the reduction valve (40) so as to produce the pilot pressure proportioning to the velocity at a secondary port (40). The pilot pressure of the secondary port is indicated by the speedometer which is connected thereto.
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