Actually, with an external BB, it's more of an issue. If the 2 bearings aren't in line then the axle isn't going to run true.
With a modern sealed square taper unit, the drive side threads need to be true but the non-drive side aren't so critical as the cup only has to hold the unit's shell in place rather than the bearings.
Actually, with an external BB, it's more of an issue. If the 2 bearings aren't in line then the axle isn't going to run true.
With a modern sealed square taper unit, the drive side threads need to be true but the non-drive side aren't so critical as the cup only has to hold the unit's shell in place rather than the bearings.