I've got a Woosh Rio MTB and the chain keeps coming off whenever I go over a modest bump, such as a drop kerb etc. Probably happens a couple of times a day and is more than a little annoying. Admittedly I'm not going at a snails pace when it comes off, but at the same time I'm not always bombing it. Does anyone else have this issue? Does the chain need a link taking out or is there any other way of stopping it happen, other than slowing right down, which isn't really an option