WHAT IS IT?
Pivot Works offers two different wheel bearing kits. The first kit is a basic package with two bearings and two seals. The second kit has two bearings, two seals and two O-ring-sealed, watertight wheel spacers. The MXA wrecking crew opted for the kit with the watertight wheel spacers to help extend the life of the new seals.
WHAT’S IT COST?
$29.95 (front bearings and seals), $24.95 (rear bearings and seals), $49.95 (front bearings, seals and watertight wheel spacers), $49.95 (rear bearings, seals and watertight wheel spacers).
www.pivotworks.com or (515) 402-8000.
WHAT STANDS OUT?
Here’s a list of things that stand out with the Pivot Works wheel bearing kit.
When the front wheel bearings on our 2013 YZ250F started to show signs of wear (side-to-side wiggling), we replaced the bearings with a Pivot Works bearing kit. We could have popped out the old bearings and put new Pivot Works bearings in for around $30 (the stockers cost $60), but we elected to upgrade the wheel-spacer collars at the same time for reasons that will become obvious in point three below. Pivot Works wheel collars have a recessed groove on their inner face that holds an O-ring. The O-ring stops water from migrating into the bearing.
(2) Bearing facts.
Believe it or not, there is a very low demand placed on the wheel bearings of a motocross bike. A typical wheel bearing is rated for 19,000 rpm, and the fastest a 21-inch wheel spins is 1000 rpm. Additionally, wheel bearings can take a 30,000-pound load, and that is more than a bike and rider can induce no matter how big the jump.
(3) Bearing life. Since wheel bearings do not wear out from landing jumps or spinning, what does wear them out? Dirt. The quality of the wheel-bearing seal is more important than the quality of the ball bearings, which is why we opted for the Pivot Works kit with the waterproof wheel spacers.
(4) Worn-out bearing.
A quick test for a worn bearing is to grab the wheel rim and apply side-to-side (axial) force to check for play. There should be less than 1/16th of an inch of side-to-side movement. If the wheel feels rough when spinning, you should check the bearings for spalling (pieces chipped off) or brinelling (dents inside the race).
Before installing bearings, take note of the depth they drop to inside the hub so that you can make sure they are fully seated. Use a brass or aluminum punch to gently tap around the bearing edges to seat the bearing, or you can use the old bearing as a punch. You should freeze the bearings and carefully heat the hub before installation to take advantage of thermal expansion.
WHAT’S THE SQUAWK?
Any basic wheel-bearing kit is worth three stars because it does its job without fanfare, but when you consider the waterproof wheel collars, the Pivot Works kit earns four stars.
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