Nothing - I have an R-Design and it was supplied with the Tempa spare wheel as a no cost option, as specified at the time of ordering.
Mine has the standard 18" wheels, however I believe that in some markets (US for instance), the R-Design is supplied with the 20" wheels as standard. Maybe there is some incompatability between the Tempa Spare wheel and 20" rims???
Someone on here is bound to know!
