dear sir or madam we can supply the following inner tubes: martin zhang huanhairubber@yahoo.com.cn size valve weight/kg 1200r20 tr179a 3.90 1100r20 tr78a 3.60 1000r20 tr78a 3.40 900r20 tr175a 2.75 825r20 tr77a 2.30 825r16 tr77a 2.20 750r20 tr75a 2.10 750r16 tr75a 1.60 700/650r16 tr75a 1.40 700/650r15 tr75a 1.35 kr15 tr13 1.25 gr15 tr13 1.05 gr14 tr13 1.00 gr13 tr13 0.95 fr13 tr13 0.80 fr12 tr13 0.65 d12 tr13 0.45