Evening, my front brake drum is a 8 inch 1/2 width unit with about eight 20mm holes in the inner face.Are the holes a "modifacation" and any ideas what bike it was originaly on?
Cheers Pat

Hi Pat..The holes were standard on those hubs when used on A10s etc. They were originally filled with 'bungs', a bit like core plugs, which you could knock out to improve cooling of the brake.
I'm not enrirely sure whether early ones were all 'blank' and later ones all had the holes or whether both types ran concurrently on different models. It is possible they were only used on models with 'sporting' pretensions..Ian

email (option): ian@wright52.plus.com