In answer to to Tom Martin's query on the subject of tyre savers.These very useful gagets were used by the cycling club folk in the 1950/60's especially by the time trialists. There were two types, one set for the use without mudguards and fixed to the front and rear brake bolts and the other type attached to both of the lower mudguard stay bolts. Holdsworth's 1967/8 Aids catalogue sold them as Carlton Tyre Savers.
Although they were very effective in clearing debris from the tyres the mudguard type were found to be a potential hazard as they would sometimes buckle up and jam the wheel causing breakage or even worse a spill. I still have some of these in my collection and decided for the purpose of my safety thats were they will stay!