Originally Posted by
Lemond1985
Your valve stem serves as one. You can always tell your hubs are in good shape when a spinning wheel settles gradually, with the valve stem winding up in the lowest possible spot on the wheel.
I don't think so.
When I worked as a shop mechanic I installed a lot of bike computer wheel magnets. I assumed the bast place on the wheel to install the magnet would be the lightest point so I'd let the front wheel find it's balance point. Most often the lightest point was near the valve stem. If you think about it, when they make a rim, they remove material to make a hole for the valve stem and they add material where the extrusion is joined together.