Bicycles Stack Exchange is a question and answer site for people who build and repair bicycles, people who train cycling, or commute on bicycles. It only takes a minute to sign up.
Sign up to join this community
I have a shimano altus rear derailleur that won't go into biggest cog for gear 1 - it is two out so in the gear 3 cog. Would it be the limit screws needing adjustment or other?
I have tried adjusting the higher and lower limot screws, but the derailleur doesn't seem to be moving in or out when adjusting. What could be causing this?
The jockey wheels are not aligned
No. The limit screws should be set once then left alone. If you've fiddled the limit screws, then turn them back. Limit screws control the edges of range of the derailleur, and that's all.
Position the limit screws such that the cage+jockey wheels cannot go outside the line of the outermost cogs on your cassette. There are two screws that physically limit the travel of the derailleur. If labelled, the L is normally the LOW gear (easy, most teeth, nearest wheel) and H is the HIGH gear (hard, least teeth, most-outboard from centerline)
Set them by loosening the inner cable pinch bolt, and the derailleur will move to the outside, though chain may get in the way. Physically turn the screw until the jockey wheel is about in-line with the smallest cog. Leave it alone.
The other side is a little harder - you need to actuate the derailleur by pushing on it and not chomping a digit in the moving parts.
In the Low gear, limit should be set just outboard of in-line with the largest cog. It is bad if the chain jumps over the top of your cassette and down the back. Ideally the chain should just make it there and no more. A little clatter here is okay.
Some minor tweaking of limit screws may be needed later in the process, but probably no more than a 1/4 turn total.
When they are set right, you'll never need to touch them again unless changing components.
The derailleur is only actuated by moving the shifter. My method for getting it in the ball-park is to get the bike in a stand or off the ground, then
This should be about right, but you then use the barrel adjuster to fine-tune things. Tightening the adjuster will effectively shorten the outer housing allowing more inner cable which moves the derailleur to the right, or harder gears.
Conversely backing out the adjuster effectively lengthens the outer housing, putting more tension on the inner cable and moving it toward the easier gears.
Many bikes work perfectly in some gears but have a slight chatter in others, more-so when on the workstand. Simply shift up and down the cassette while slowly hand-pedalling, looking for a sweet-spot.
This kind of thing is fiddly and dirty, don't get put-off.
