I have a 2012 Spot Acme and it's been great, everything is still smooth and working well into its second winter. However I picked it up to bring it into the office a week ago and noticed grease all over my hands, just like a chain would do. Here's a picture.
It's like a heavy black graphite grease, definitely oily and not just dirt. There are no signs of leakage from the Alfine SG-700 hub or the bottom bracket. (Hub oil is a much lighter product more like automatic transmission fluid and there is only 25cc of it.) If either the hub or the bracket had leaked all its lubricant I would expect at least some creaking or other noise but it's still all smooth and silent.
I haven't ridden in anything but normal wet weather. If I had gone through a big puddle of grease I would expect to find some on the frame, my clothes, experience disc brake issues - but everything else is clean.
Gates technical support says that the belt would not deteriorate so quickly and even if it did it would not release any residue, and that it can be removed and cleaned with no ill effects.
Any suggestions as to what I should check next? If this stuff came out of the bike then something needs some attention. If it didn't, how can it be confined to the belt and sprockets?
Update: It almost certainly is a leak from the Alfine 11 hub, Spot Bikes say it has been known to happen and there are a few search hits with people describing exactly this problem. The bike is in for service with a local shop now (under warranty), I'll update again with the outcome. Annoying to be without a bike...
Second Update: I'm picking up the bike tonight, after a cost-free fix under warranty. The hub was inspected by Shimano's representative and pronounced OK once the seal was replaced. The Gates drive components were decontaminated and everything is said to be fine now. If I experience any further leaks, shift issues or if exposure to Shimano's $$$$$ hub lubricant has had any negative effects on the drivetrain I'll continue the saga here.
Third Update: I've put a few hundred km on the bike after the fix and everything seems OK in terms of seal. I might be mistaken but it seems be slipping a bit more often when I put a lot of power on the pedals. I'm watching it and will start making some noise about a complete replacement from Shimano if it gets worse.
Fourth update: It's leaking again. Have asked the bike store to talk to Shimano about replacement :-( When it works it is a nice product but at this stage I would not recommend it to anyone - maybe if they give me a replacement and it works for 12 months with no leaking I might change my mind.