The Dyson DC25 has a fatal design flaw that causes the drive gear in the beater brush to often fail. Unlike other vacuums, if the beater brush gets tangled up with hair or carpet fibers, the belt isn't engineered to give way, so either the motor or drive gear tend to break instead. Don't pay $120 to replace an entire beater brush head when all you may need is a new drive gear. The factory gear in my first beater head failed a month after the warranty expired, leading to a costly replacement head. The gear in the second head did a little better, but still died three years later, so I created this part instead.
This drive gear for a Dyson DC25 vacuum cleaner replaces the factory part that Dyson should--but doesn't--sell as a standalone replacement part. It has been painstakingly re-engineered, and features a thicker reinforced sidewall that should give it a longer life. I recommend printing it in flexible and strong (nylon) plastic.
Before purchasing, use torx screwdriver bits to disassemble the beater brush head and insure not other parts are warped or broken. Note that there is a hidden torx screw in the beater brush insert shaft that connects the insert to the drive gear.