Originally Posted by
hevysrf
Can you explain how skewer tension can affect bearing adjustment when both the cone and jam nuts are threaded?
See
Park Tools and
Sheldon Brown for more on this.
Sheldon is correct about the axle compressing slightly; Park is incorrect about the axle flexing, but both are correct that bearings of hubs with Quick-Release axles must be left slightly loose when the wheel is off the bike. An easy way to adjust the bearings correctly, with the axle under compression, is to use an axle vise like
THIS ONE.