While true that visitors and hosts compete on the same baskets, all 18 inches in diameter, the prevailing wisdom remains – the home team is accustomed to its own bounce. So if the feel differs from city to city, it’s a perceived disadvantage to the visitors.
Christopher Arena, the NBA’s vice president of apparel and sporting goods, said every rim is thoroughly tested and measured. A contractor named Drew Sorensen travels to all 30 NBA arenas in the preseason to set each rim. Sorensen uses something called the ERTG Rim Tester, which measures the “rim flex,” a computation based on energy absorption. A weight is dropped from each rim and a tiny microprocessor calculates the flex. The higher the rim-flex number, the softer the bounce, and the more likely your shot will roll in when maybe it shouldn’t have.
Each NBA team is required to buy new rims at the outset of every season – new backboards must be purchased every five seasons – and the league mandates a rim-flex reading of 20 to 35. Once Sorensen signs off on the measurements, he theoretically locks that number in place for the season by placing pieces of tape over the brackets that connect the rim to the backboard brace. Those pieces of tape each have a seal with holographic imagery. If a visiting team were to complain about the flex, the NBA can “go to the tape” to discover whether the rim has been illegally altered.
Sorensen returns to each arena once during the regular season, once during each playoff round and then resets the rims for every NBA Finals game.