The aim of this research is to study the brake proportional affected to vehicle stability. Braking performance and vehicle stability testing are the main of research purposes. Otherwise learning research center and new researcher in automotive engineering are the minor research objectives. The results of research discovered to the braking performance depend on driver behavior. By the minimum deceleration was appeared on the non-proportion in front axle with braking ratio 0:100. In term of vehicle stabilities yaw and pitch moment are normally occur by the driving behavior. But the sideslip is an absolutely effect to vehicle handling. With the braking ratio 100:0 there is the highest risk for controlling a vehicle cause of the wheels were locked-up condition in the rear axle. Therefore the value of the sideslip was exceeded with the criteria. Furthermore these project researches were got the learning research center and the new researcher in automotive engineering field.

A disc brake is one of important auto parts for motorbike cycle industry which effected directly to life safety. As the result this project aims to test the performance of the disc brake in order to study the physical disc brake that effects to braking distance and to be an alternative for testing the brake disc. The braking performance tester was designed and created in the single dynamometer which was not over 10 Hp and the 17of inertia .70 kg. m. Referring to testing state of JASO T204:2001 standard this tester focused on testing the 3 different types of disc brake i.e. normal type grooving type and perforated type. The tested temperature was at normal state of the brake disc temperature (60° C - 80° C) and at high state (more than 100° C). The braking force from 9.81 N to 34.33 N at master cylinder was tested. moments was not over 92 The result revealed that at normal temperature the braking performance of the three disc brakes (normal type grooving type and perforated type) was at 17.76 21.80 and 19.00 per 1 mrespectively. However the brake performance at high temperature was at 14.41 18.06 and 18.93 per 1 m. This meant that the most efficient disc brake at normal temperature was grooving type of disc brake which was 22.74% different from normal type of disc brake. Nevertheless; the perforated type of disc brake was the most performance disc brake at high temperature which was different from normal type of disc brake at 25.32% 2 of contact surface areas 2 of contact surface areas respectively2m/s2m/s

Nowadays the automotive parts industry greatly grows up in Thailand. Brake disc is one of products that play a role in safety area. As a result the various designs such as front and back-vented brake discs are occurred to improve the performance of usability. Consequently this study aims to develop the ability of braking dynamometer from 9.7 kg-m.1 kg-m. Moreover the influence of the front and the back-vented brake disc effecting on braking distance was investigated by single dynamometer referenced JASO C406 for testing condition. Therefore both of discs were operated under 100 200 and 300 °C of braking temperature and 2 4 and 6 MPa of line hydraulic pressure of braking. 2 to 1272 of moment of inertial From experimental works the test results reflected that the back-vented brake disc created braking distance shorter than front-vented brake disc ostensibly. Besides there are also diversity of factors as temperature pressure and initial speed of braking. Especially the higher temperature caused an increase of deceleration and a decrease of braking distance. Moreover the higher pressure produced a deduction of braking distance and a rise of deceleration. Finally the initial speed of braking was directly various the braking distances in same condition.

A disc brake is one of important auto parts for automotive industry which effected directly to life safety. The wear of brake rotor war affected to the brake efficiency. Lf the wear of rotor was discovered while operating the risk of accident shall be reduced. Therefore a study of disc wear affected to brake distance was the one of alternative for the brake efficiency testing. From this reason the aim of project is to test brake efficiency from the wear of brake rotor with the experiment conditions from JASO C 406 [1]. By the test conditions are focused on 3 cases of the wear: rotor little roughness rotor and abundant roughness rotor. The conditions of experiment consist of 100 200 และ 3000C on the rotor surface operating pressure 2 4 and 6 MPa initial speed before brake applied 50 and 80 km/hr. Based on the result of experiment was revealed that the braking distance deceleration and the brake ability with deceleration per unit of area. The result of experiment shown that the ordinary rotor at 6 MPa 300 0C and 50 km/hr. is given to the shortest of braking distance 69.7 m. Although the average of deceleration and the brake ability is take up on little roughness rotor. In case of the longest braking distance was occurred on the abundant roughness rotor. However from this study is discovered to the high temperature and the high pressure is significant to the braking distance shortened.

The aim of this research is to create the center of mass testing machine for vehicles with maximum mass 3000 kilograms. By the performance of this machine is able to determine the center of mass 3 axis by horizontal longitudinal and vertical. On the other hand the verities of mass from 50 to 250 kilograms and the several of weight distribution at horizontal and longitudinal are applied to the condition of testing for reasonable to the position of the center of gravity for vehicle. The result of research discovered to the performance of center of mass tester was activated following to test conditions. Furthermore the position of the horizontal of center of gravity depends on the weight distribution at horizontal axis and an increasing of mass under non-uniform along the longitudinal and horizontal axis. In term of the position of the longitudinal of center of gravity the weight distribution at longitudinal axis and an increasing of mass rate are points. Otherwise the weight distribution at longitudinal axis and an increasing of mass are effect to the position of the vertical of center of gravity.