Originally Posted by
johnadarin
Does anyone know why the chain keeps on falling off on my Giant Seek 1, when I switch gears too quickly or when there is an extreme distance between the front and rear gears? I need to find a solution because it's making me crazy.
I went to my local bike shop and he said that there's nothing to adjust, and to just keep the front and rear gears lined up, somewhere in the middle at all times. What would be the purpose of having 27 speeds if I can't use them all? Thanks, John
2011 Giant Seek 1
1977 Peugeot PX10LE
Define "When there is an extreme distance between the front and rear gears" please. Are you referring to being in a small chainring in the front while on the largest cog in the back, and vice-versa?
A chain that's too long, or a wheel sliding in the dropout is one possible cause. Is the rear wheel seated as far back as possible? Barring that, possibilities are:
Is it falling off to the inside or the outside of the cranks? If it's the inside, you can install a chainkeeper. Because of the large tooth jumps to the small ring on a triple, it can be difficult to have both good shifting and yet keep the chain from jumping off the small ring. A chainkeeper/dogtooth/etc will help take care of that.
If it's falling off the large chainring to the outside, then you need to adjust the high limit screw on the front derailler.
In either case, your LBS guy is either lazy or incompetent, possibly both.
Also, on a triple, you really don't get 27 gears. You should avoid the small/small and large/large gear combinations. It's also likely that you have a fair number of gear ratios that are so close as to be effectively the same. That's just the nature of a triple/