size            P.R   standard rim    section width(mm)    tube/tube less
29.5-25     28      25.00/3.5           750                                TL
26.5-25     28      22.00/3.0           675                                TT/TL
                   24
23.5-25     20       19.00/2.5           595                               TT/TL
                  16                                                                                     
                    20
20.5-25                 17.00/2.0           520                               TT/TL 
                    16                                                                                  
                     20
                     16
17.5-25       14       14.00/1.5           445                               TT/TL
                     12                                                                                    
14.00-24     20 /16       10                  875                              TT      
16.00-24      24/20        11.25           405                               TT     
15.5-25         12              12.00/1.3    395                               TT    
16/70-20       14                13.00/1.3     41O                                   TT