I'm looking to determine what is the correct stock front brake drum ID. I have two '31-'36 front brake drums. H-D Parts Book notes these also fit '30-'40 RL/WL. My very used brake drum that I run on my bike measures 9.860" ID resulting in a hub thickness of .030"-.035". My spare brake drum measures 6.742" ID with a hub thickness of .100". Bruce Palmer's H-D restoration book notes these brake hubs as having a 6 3/4" ID, which matches closely to my spare drum.
I'm hoping other members may have a some spare drums they can measure and post a response, or have the measurement noted in their archives. Thanks for your help in advance.
I'm hoping other members may have a some spare drums they can measure and post a response, or have the measurement noted in their archives. Thanks for your help in advance.