STATIC WEIGHT DIS­TRI­BU­TION

NZ Performance Car - - Weekend Workshop -

Static weight dis­tri­bu­tion is best de­scribed as the weight rest­ing on each of the four tyres with the car loaded as it is usu­ally driven. Full race mode must be in ef­fect when set­ting up static weight, which means the driver should be seated in the car, with a full fuel tank, and cor­rect tyre pres­sures (yes, this will af­fect it). Static weight dis­tri­bu­tion cov­ers two key weight per­cent­ages, left to right and front to back.

In a per­fect world you want a left to right bal­ance of 50% each side with the driver in­cluded. To find the left-weight per­cent­age, add the front left wheel weight to the rear left weight and divide the sum by the to­tal weight. Sim­i­larly, to find the rear-weight per­cent­age, add the left rear wheel to the right rear weight and divide the sum by the to­tal weight. A 50/50 bal­ance is usu­ally the ideal goal for a rear-wheel drive cir­cuit car, although front-wheel drives — like the Honda we weighted — want closer to 60/40.

Ad­just­ing static weight dis­tri­bu­tion can only be done by mov­ing weight around the car, so for in­stance you could move the bat­tery closer to the left side to in­crease its per­cent­age or fur­ther away to de­crease it. Adding bal­last is an­other op­tion — but comes at the cost of added weight.

WITH THE CIVIC ON THE SCALES, AND THE DRIVER IN THE SEAT, THIS IS THE FIRST READ­ING THE SCALES GAVE US. WITH A FWD HONDA, THE IDEAL REAR WEIGHT PER­CENT­AGE WE WERE SEARCH­ING FOR WAS 40% — A 50/ 50 BAL­ANCE ( USED ON RWDS) WOULD MAKE THE CAR TEND TO WANT TO SPIN DUR­ING HARD COR­NER­ING. THE 37.24% START­ING POINT WAS NOT ALL THAT BAD. IN OR­DER TO IN­CREASE THE REAR PER­CENT­AGE, WE TRANSFRED WEIGHT REAR­WARD AND ENDED UP WITH 39.4% WHICH IS VERY CLOSE TO OUR GOAL. AS YOU CAN SEE BY THE SCALES, THE RIGHT HAND SIDE’S BAL­ANCE WAS ALSO CLOSE, BUT RE­QUIRED A LIT­TLE MORE WEIGHT TO COM­PEN­SATE FOR THE DRIVER’S WEIGHT.