Up until now the Brompton has run flawlessly. Out on my ride yesterday I noticed some chattering (best I can describe it) noise coming from the rear 3-speed hub as I was slowing down for a traffic light. I stopped short of the light to visually look and see if there was any noticeable problem. I started pedaling again and the chattering, or whatever, was still there. I was in mid gear at the time. I flipped through the gears on the hub (not the 2-speed derailleur) and all was fine when I pedaled away from the light. Any ideas as to what that was or caused it? I examined the bike, and the adjustment for the hub is bang on. Once in awhile I have noticed an occasional odd/different sound while coasting in mid gear. At least it's still under warrantee in the event there is a problem with the hub.