Giant Simple 3. I'm a clyde and I use this bike for utility, so I know I load it up a lot. Shortly after I got it, it threw the chain. Went back and had it dealt with; I don't have room for a stand or anything and it seemed like a warrantee thing. Other issues came up (broken rear spokes). But the chain kept throwing. They took the bike in, drilled a new hole to take the rack completely off of the axle, and put some sort of restrainer to keep the rear axle from moving, tightened it all up, gave it back. I ride it a couple days and the chain comes off during moderate acceleration on flat ground.
When it throws, it comes off of both sprockets. Don't know if that's relevant.
Someone was looking at it and remarked that he thought that the chain was tight when I was sitting on the seat, but when he checked again in the exact same spot after I stood it was loose. I can't verify that.
Any thoughts what might be going on? This is getting old; i'm getting tired of having my chain come off in intersections and having to coast out without brakes.