PURPOSE: To improve stability of a car provided with two front wheels and two rear wheels by making such that tread length of front wheel ≥ tread length of rear wheel.

CONSTITUTION: Two front wheels 2 and two rear wheels 3 are provided on the saddle frame of riding type four wheel car body 1 while low pressure balloon tyres 4 are arranged on each wheel 2, 3 to employ a bar handle 5 for steering of front wheel 2 while bar step 6 for the step and to set the tread lengths (a), (b) of front and rear wheels 2, 3 such that a≥b. Consequently, transfer of the center of gravity upon turning is reduced to facilitate turning without requiring unnatural transfer of body weight resulting in improvement of stability.