I have got a gym ball from Asda a while and although its advertised as a 65cm it actually only 55cm when inflated fully. Its not faulty and after looking at reviews on amazon of similar balls this isnt uncommon!
direct.asda.com/Gym-Ball/000934084,default,pd.html#descriptionSection
Remember this was the same as cheap ball from Argos.
Does anyone have any good recommendations for a true to size 65cm one?
Thank you!