- Rennen Sprockets are precision machined from aircraft quality 7075-T6 Aluminum ( 83% stronger than 6061) and polished to a beautiful luster or available in Stealth Black, offering the highest performance at the right price. Rennen Chainrings are 3/16" thick and are made to take the abuse of the BMX Track or a east coast muddy rocky SS ride. Only Rennen Sprockets offer a single speed specific tooth profile which have been designed to extend tooth life. At 2.8oz (79 grams, 38T) this makes Rennen Chainrings one of the lightest on the market.