Hi everyone. I have just physically counted the teeth on the rear of the Airlite. The larger cog has 28 teethe, and the smallest cog has 12. On the front, the larger of the two 'rings' has 50 teethe. I haven't managed to count the smaller front ring. The only label on the rear states that it is a 7 speed SIS index. It seems the 2014 limited edition Airlite has an updated cassette than the internet reviews available. I have googled the difference between a 28 toothe cog and a 30. There are two opinions; that the 30 toothe cog isn't much better than a 28, and yet others think the 30 just gives an extra edge. Others opinions I have read on discussion threads suggest leaving the mech alone and buying new wheels to take some of the weight off a bike. Another suggestion I read stated that the person asking about cassette issues should loose some body weight and get fitter. Perhaps at 55 I'm just getting older.