The below are the tyre sizes to suit 21″ Rim [Sorted by tyre width]

225/30R21    
235/35R21    
245/30R21      245/35R21      245/40R21
245/45R21    
255/30R21      255/35R21      255/40R21
255/50R21    
265/30R21      265/35R21      265/40R21
265/45R21      265/50R21  
275/30R21      275/35R21      275/40R21
275/45R21      275/50R21  
285/30R21      285/35R21      285/40R21
285/45R21    
295/25R21      295/30R21      295/35R21
295/40R21    
305/25R21      305/30R21      305/35R21
315/30R21      315/35R21      315/40R21
325/25R21      325/30R21      325/40R21
345/25R21    
355/25R21