It is nearly impossible to manufacture a perfectly balanced, perfectly round tire. Each tire has a high and low point, mainly where the belts are joined, and these points cause vibrations when a tire is rolling. Companies attempt to minimize this variance, but they can only get so close to perfection. Manufacturers measure the high and low points of the tire and identify irregularities by applying red and yellow paint dots. These dots help tire and wheel assembly and balancing. Properly balanced tires and wheels are key to ride quality and safety.

● RED DOTS

The red dot indicates the tire’s highest point. We imagine tires as perfect circles, but in real life they are slightly egg shaped. Red dots show the highest point of out of geometry (edge of the egg) In many cases, wheels also have a marking to indicate its low point, drilled dots or stickers, which are called harmonic points. When the assembler matches the red dot of the tire with the wheel’s harmonic low point, these high and low points cancel each other out thereby reducing out-of-roundness.

● YELLOW DOTS

Due to irregularities during manufacturing, materials within the tire are not distributed perfectly even. This means that the tires have a heavy spot and a light spot. Yellow dots indicate the lightest point on the tire. The valve stem is considered the heaviest point of the wheel. Assemblers minimize these weight distribution variances by aligning the lightest point of the tire (indicated by the yellow dot) with the heaviest point of the wheel (the valve stem). This alignment is known as match-mounting and results in the best possible pairing of the tire and wheel. This process reduces the amount of weight correction required when balancing, saving material and producing a more aesthetically pleasing assembly.