Gears slipping help
 

I am having trouble with my gears not staying in gear. When I am in 3rd gear and hit a bump or climb a hill my gears slip down on the 4th ring. I have to shift the shifter back to the 2 position to get it back into 3rd gear. What causes this and how do you fix it.?

Park Tool is your friend. Your cable is probably improperly adjusted. I would skip all the stuff on adjusting the high and low limit (those usually don't go out of adjustment) and go straight to the bottom of the page about adjusting the cable tension.

If the bike is old and you've changed the chain recently without changing cogs, you can have a chain skipping problem there too but that usually manifest itself as a popping of the chain and not a shift. Just to be safe look at the section on chains too.

Agreed with Cyclo......sounds like a cable tension issue. Easy fix! Info here as well! Simple and easy to understand!http://www.bikewebsite.com/repair-bike-index.htm :D

Have fun! Ride safe!

Ditto. That was the problem I was having the past couple of weeks. It was the cable tension.