
Nike is offering free drivers to anyone who purchased one of their square Sumo2 drivers because they are loaded. Turns out the design of the drivers exceeds certain parameters laid out by the USGA. A competitor to Nike ratted them out. The Sumo2 drivers break the allowed characteristic time. I can’t figure what that means, so here’s an explaination from ESPN:
Characteristic time (CT), which is measured by the so-called “Pendulum test,” refers to a driver face’s tendency to deform slightly at impact, resulting in improved ball speed. The USGA and R&A set a characteristic time limit of 239 microseconds, plus a tolerance of 18 microseconds. This correlates to the previous coefficient of restitution (COR) test and its limit of .822 with a manufacturing tolerance that extended to .830. By comparison, a wooden-headed driver has a COR of about .780.
Nike has a little video on their golf site saying ‘oops.’
A couple pro golfers have been using the Sumo2, including K.J. Choi. Choi won the Chrysler Championship back in October. The Nike Golf video says Choi used an honest driver. But looking at his 2007 performance maybe he should switch to the loaded ones.