Here is an interesting excerpt from circle track magazine. They actually found that having the angles EQUAL AND OPPOSITE made more HP at the tire then getting the driveshaft as straight as possible...

VERY interesting...


"At the end of the last set of runs, we experimented with pinion angles and actually learned some interesting facts. Our Winston Cup consulting engineer, Terry Satchell, told us the most important factor in pinion/driveshaft/transmission angles was to have equal angles at each end of the driveshaft. This would be the most efficient design, yielding less loss of horsepower from bearing bind at the chassis attitude that is the result of the car accelerating. What we discovered was not what we had expected.

We did experience a slight gain in horsepower due to changes in the pinion angle. We could not change the transmission angle, so all of the changes were to the pinion. We recorded a run at zero pinion angle and then at 10 degrees of pinion angle. We expected a loss in horsepower at the greater pinion angle, but actually experienced a net gain in horsepower. This was very confusing until we thought about what Terry had said. When the pinion was at 10 degrees, the angles at the ends of the driveshaft were opposite and closer to equal. This was a better situation providing less resistance than when the pinion was at zero degrees with the transmission angle at a much different angle.


Most racers only measure the pinion angle relative to the ground when they should measure both the pinion and transmission angles relative to the driveshaft. The angles should be equal and either opposite or in the same direction to help eliminate vibration and drag through the U-joints.

This yields more rear wheel horsepower as well as longer component life due to vibration-free movement as the bearings rotate.
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