MRTC-BD716

　The fate imposed upon those who continue to lead is to always strive for even greater heights. The challenge for the BD7 2016 was to overcome the significant hurdles it had set for itself and to improve both speed and drivability. Chief mechanic Kojiro Umino, who led the development of the World Champion BD7 series, focused on the keyword "ultra-low center of gravity." It was a bold idea: rather than resting on the performance honed at the pinnacle of the world racing scene, he fundamentally re-examined a machine that already possessed a low center of gravity.

　The reduction in diameter of the front and rear differential pulleys, derived from careful testing, resulted in an ultra-low center of gravity design that allows the chassis components to be mounted lower for overwhelming cornering speed. Furthermore, reducing the diameter and weight of the differential pulleys lessens the gyroscopic effect, improving the machine's handling performance and throttle response—a choice that makes sense from various perspectives. In line with this, the shocks have been shortened in length and increased in diameter to ensure sufficient damping force. Double-joint universal shafts come standard on the front, ensuring the car is fully prepared for racing. Of course, these choices were only possible because of the BD7's ultra-high-precision chassis; it is no exaggeration to say that this is the embodiment of a design philosophy that meticulously refined every single part and elevated them to perfection through flawless balance.

　The position of the center of gravity is the most important factor when discussing a car's handling and driving stability. The lower the center of gravity, the lower the load transfer due to roll and pitch; reduced load transfer minimizes fluctuations in the contact load of individual tires and suppresses changes in posture, allowing for a balance between calm behavior and responsive handling. Conversely, if the center of gravity is high (as in many current touring cars), measures such as strengthening the shocks or stabilizers are necessary to minimize roll and pitch, making it difficult to follow road surface gaps. In recent years, with the trend toward higher speeds and higher grip in touring car racing, it has become increasingly difficult to stabilize machine behavior. The BD7 2016 has once again reviewed its fundamental performance, and by building upon the know-how cultivated thus far, it has achieved a surprising step up.

　The front and rear drive pulleys have been reduced in diameter by 6mm, lowering the center of the drive axles by 3mm. This reduces the gyroscopic effect caused by rotating objects during operation (the effect where the axis of rotation becomes harder to change), improving movement, especially in the roll direction, and enabling sharper cornering and quicker transitions. Furthermore, the weight reduction of the pulleys improves throttle response, providing positive effects on acceleration when exiting corners and fuel efficiency.

　The front and rear bulkheads, which account for a large portion of the chassis's weight, have been lowered by 3mm at the top of the upper bulkheads. The upper deck has also been lowered by 2mm, contributing significantly to the overall lower center of gravity. By lowering the center of gravity relative to the roll center, excessive roll is reduced during high-grip driving. In today's racing scene, which often tends toward excessive grip, this is highly effective in preventing traction rolls. Moreover, it allows for setting adjustments without over-reliance on stabilizers, making it possible to achieve more neutral steering characteristics.

　The shock towers, which are located at the highest point, have also been lowered to contribute to the lower center of gravity. Compared to the standard rear shock tower of the BD7 2015, it is 7.8mm lower, and it is 5.3mm lower even compared to the short shock specifications that were previously an option. Short-type shocks are standard equipment.

　Short shocks are not simply shorter in length; their capacity has been significantly increased by expanding the inner diameter of the cylinder. The new Super Low-Friction Short Shock "II" increases the cylinder inner diameter from the previous 10.2mm to 11.2mm. This not only significantly increases capacity compared to the old short shocks, but it also achieves approximately 20% more capacity than the Yokomo SLF standard size, which was previously considered a large-capacity option. Previously, it was said that shortening the shocks would make handling feel peaky, but the SLF Short Shock "II" handles the increased demands placed on the suspension by higher speeds, providing high handling stability. In addition, the increased capacity reduces viscosity changes due to heat during driving, which leads to consistent performance with fewer characteristic changes during a race.

　The front double-joint universal shaft, which reduces driving loss during steering operation, is now standard equipment. When driving with a front solid axle, which is the current mainstream driving style, the steering angle during cornering tends to be larger, often resulting in a feeling of speed loss. By making the double-joint universal shaft—an essential item for racing—standard equipment, the BD7 2016 achieves natural turn-in and improved cornering speed. Additionally, with this standardization, the retail price of the double-joint universal shaft has been reduced to ¥4,980 (excluding tax).