I replaced the Excelsior 500 x 16 tyres on my +4 with 500/525 x 16 Pirelli Stella Bianca, from Longstone. They are fine but I did have a problem. The overall diameter is slightly larger which meant the spare didn't fit in cradle. Mine is a 4 seater so the spare sits vertically in the cradle and bolts onto a bracket on the rear. The added diameter pushed the wheel too high to allow the bolt to engage with the bracket. So I have an old. unworn, Excelsior spare wheel.
