I just ordered a few metal reels with the bigger center hubs. When I assemble my Super-8 film footage onto one reel I do it on an "edit bench" with rewinds. The rewinds will help ensure that I get the proper tension on the film as it winds onto the movie reel. Metal Reels work better than plastic for this application. Without the proper film tension and metal reel, when the film is put on a Rank, Spirit, or Shadow for transfer, the film can "cinch", which is very bad. Cinching means the film rubs against it self as it tightens due to an outside force pulling on it. Cinching usually means the film has been scratched. Cinching is like getting a rope burn or a paper cut. The Metal Reel on a Rewind system will allow for the proper tension when the film is being collected onto one reel, and the bigger hub diameter should help minimize reel wobble.
The metal reel with the bigger diameter HUB (4 inches) will be more reliable when actually transfering on the Rank, Spirit, or Shadow. Movie reels that have the very small diameter HUB may wobble which usually results in the film rubbing against the movie reel wall (is that called the flange?) during the transfer. The film rubbing against the movie reel can actually add a "jump" to image as it is being transfered to video. Everytime the movie reel's rotation reaches the "untrue" spot on the reel, the movie reel may touch the film, and that can be quite an expensive and messy problem to fix during a transfer session.
