Bontrager's Big Earl wheel set is known as one of the most strong and durable sets available for your bike today. Featuring an oversized, extra-wide rim and a beefy hub with the option to run a normal quick-release or a 10mm through-axle, the Big Earl has become one of the most popular downhill and all-mountain wheel sets. The bearings in the Big Earl rear hub are sealed bearings, meant to last for years before needing to be replaced, but eventually, you'll need to open up your hub and pop some new bearings in place to keep rolling smoothly.
Loosen the quick-release lever on the non-drive side of the rear wheel to loosen the axle. Pull the wheel downward out of the rear wheel dropouts and away from the bike.
Wrap a chain whip around the cassette clockwise to keep the cassette from spinning. Set a cassette lockring remover on the lockring of the cassette and spin it counterclockwise with an adjustable wrench to remove it. Slide the cassette off of the free hub body and set it aside.
Twist the quick-release nut off of the quick-release skewer and slide the skewer out of the hub of the wheel. Set a 15mm cone wrench on the end-nut on each side of the hub and twist them each counterclockwise to separate them from the hub. Slide the axle out of the hub and set it aside.
Insert an 8mm hex wrench into the end of the free hub body on the drive side of the hub. Turn the wrench counterclockwise to loosen and remove the free hub body. You should now be able to see both the drive and non-drive side bearings of the hub.
Use a flat head screwdriver or similar object to ry the existing bearings out of the hub. The bearings should come out relatively easily as the bearing cups are greased in the factory before the bearings are set in place. Set the new bearings in the bearing cups. If this proves difficult, use the end of the axle you removed previously to push the bearings into place.
Slide the axle through the centre of the hub and twist the endcap nuts back onto the drive and non-drive side ends. Use a cone wrench to tighten the endcap nuts in place. Slide the cassette back onto the free hub body of the hub, then twist the cassette lockring clockwise into place to secure the cassette. Use the lockring remover and an adjustable wrench to tighten the cassette lockring.
Slide the quick-release skewer through the hub centre with the quick-release lever on the non-drive side. Twist the quick-release nut onto the end of the skewer clockwise then slide the wheel up into the rear dropouts of your bike. Close the quick-release lever to secure the wheel in place.
Bearing replacement procedure for the Big Earl wheel set differ by the year in which the wheels were manufactured. Refer to your owner's manual for any directions specific to the model you own.