Originally Posted by supcom
You may not find a hub labelled as 120 mm. Generally, the hub and freewheel together will most likely be less than 120 mm wide. you add spacers between the cones and locknuts to bring the locknuts out to the desired width. You also may need to use different length spacers to maintain the correct chainline.
Hmmm, most of the hubs I've found so far are actually labelled/denoted as 124mm... one said to take the spacers OUT to achieve 124...