gears were slipping on the middle chainring when out yesterday, and it was doing it again this morning on the way to work. Made it tough going only being able to use the bike ring or 39x21-25. Wasn`t the chainrings as they were only replaced about 1000-2000 miles ago, and it was a relatively new chain. Slipping badly on the way home, and even started doing it in the big ring too. Chain seemed a little loose, so I had my suspicions it was the rear derailleur jockey cage tension spring. Turned out I was right as it was barely springing back at all to take up any slack. Plenty of GT85 and it`s nice and springy again. Jury is still out on whether it`s sorted the problem - fingers crossed for a frost free night to test it tomorrow on way to work.