The typical wire wheels with steel rims are not noticeably lighter than a steel disc wheel. However, if you look closely at the wire wheels on the Stirling Moss 300 SLR "722" you will see the sort of light weight alloy rim wire wheels, often made by Borrani or Rudge, that were fitted to high performance racing, sports and grand touring cars for decades. The splined hub with eared "knock-off" fixing nut allowed for quick tire changes in competition. In the drum brake era, wire wheels were favored in competition because they allowed maximum exposure of the drums to cooling ambient air. Still in use in the disc brake era, they were eventually supplanted by lighter and less maintenance intensive alloy wheels with large cooling slots developed by Dunlop, Minilite, American Racing and others.