Cant get all my gears!

fto-si

I had a troublesome commute home on my new Orbea today, it wasn't indexing gears to well I have been tweaking the barrel adjuster to try and sort it.
Now I cant get the chain to move onto the largest sprocket, the other sprockets are indexing fine so before I start tweaking the adjuster again ( and probably making it worse! ) can anyway tell me any likely reasons the chain is not going onto the largest sprocket?

alfablue

I think you need to wind your barrel adjuster out a bit, this will increase the cable pull and get the chain on your largest sprocket. The best way to set it up is (if poss) to put the bike on a workstand and look at the rear mech guide pulley from behind the rear wheel and adjust the rear mech until it lines up perfectly with the cassette sprockets.

It could be the limit screws are set wrong but it is unlikely if the gears were working fine before, so I won't go in to that.

Have a look at the Park Tools web site for the full story.

Cajun

If this just started happening, I'd say that your cable has stretched.....you just need to remove some slack.. If you've done some to/fro adjusting, just take it to the LBS and they should be able to correct it within minutes...

k-dog

It's easy to do so you should be able to sort it yourself.

Cable stretching would seem to be the obvious culprit but it's easy to check the whole thing.

Do you have an extra click when you go to the smallest sprocket? - by that I mean that if you change all the way to the smallest sprocket one click at a time can you click the shifter once more and nothing happens?

If so you've just loosened your cable too much and you need to back that off - you've basically gone one index stop too loose. Just tighten the barrel adjuster until you can get into that top gear - and make sure that changing the other way is smooth too.

If that doesn't do it then I would start from the beginning.

Get your bike off the ground so you can turn the pedals. Wind the barrel adjuster all the way in. Change down to the smallest sprocket and then pull the cable by hand (under the downtube is the easiest place) to make the rear derailleur move - pull it as tight as you can and see if you can get into the biggest sprocket. If you can't then the limit screws need adjusted - the derailleur isn't moving far enough to allow you into that gear.

If you can get in that gear then you just need to refine the cable tension. Try changing gear and it should not quite go (because you wound the barrel adjuster all the way in). Give it a turn or so and try again. Keep doing that until the changes are crisp.

Then make sure that downchanges are smooth - it's a case of balancing the two