I have a 'space saver' spare on mine. Technically it's a standard 4/4 wheel, but looks tiny compared to the wheels/tyres I've got on. Unfortunately couldn't fit anything larger in the gap at the back.

"Y mae dafad ddu ym mhob praidd"
1972 4/4, 1981 MGBGT, 1984 FLHT1340, 1980 XLH1000, 1990 ZX10