Hey guys,

My bike has a shifting problem. While I'm riding it, I can not get it to shift into 3rd gear (The biggest in the front). However, when I get off the bike and try to figure out the problem, it shifts into 3rd gear just fine. Does anyone know what would prevent it from shifting while I was riding it, but not when I am turning the pedal with my hand? All of the other gears work fine.

Any and all help is appreciated!