Can't get highest gear

navrig

Got a bike with 105 front and back. For the last couple of weeks the chain would not go onto the highest (smalled cog) gear most of the time. Occassionally it would jump but most of the time it would sit on the next cog up and grind away until I added a bit more tension to the cable.

Last night I got the bike onto the work stand and ran the rear wheel whilst changing gear and turned the barrel adjuster.

Interestingly when on the bike stand the problem seemed to exist more at around gears 2,3 and 4 rather than on 10. It would often skip 3 on a down change (1 - 2 -3 - 4) and it would go onto 10 everytime.

So after a bit of fiddling back and forward I managed to get it running smoothly across the whole cassette although I could tell it was not perfectly set up.

I went out for a 35 mile spin this morning and whilst it was smoother across most of the cassette it would, again, go into 10.

I am about to go and check all the family bikes in advance of summer holiday so will have all the tools etc out. Any suggestions for sorting the problem withj my 105?

MrChuck

The only things that can really affect it are the limit screws (which sound like they're probably OK), tension on the cables, and drag between the cables and the outers.

I'm a little bit confused by some of your post (like adding tension to go down to a smaller cog- is that really what you meant?) so might have the wrong end of the stick but I'd think probably cable drag, especially if you'ver had the bike a while.

As it happens I've just 10 minutes ago finished replacing the cables/outers on my 105 and the rear shifting has been totally transformed. Before I'd also struggle to get onto the smallest cog sometimes and would often have to overshift to go both up and down. Silky smooth now. (Well, in the conservatory at least!)

markos1963

9 times out of 10 I find this problem is related to the gear cable getting mucky and gummed up. Buy a new inner, take the old one out, clean all the outers by running some WD40 through them, get a rag impregnated with 3 in 1 oil and wipe over the new cable to lube it up then set up the gears again. Do NOT adjust the upper and lower limit screws, there should be no need for it.

Twostage

Might be worth making sure all the bits of the rear derailleur are lubed up ok and there isn't a load of crud stopping it from working properly.

navrig

MrChuck wrote:

I'm a little bit confused by some of your post (like adding tension to go down to a smaller cog- is that really what you meant?) so might have the wrong end of the stick but I'd think probably cable drag, especially if you'ver had the bike a while.

Adding tension was to stop it chattering whilst in 9th after trying to get it into 10th so whilst not going up a cog size I am moving the chain slighlty up the cassette.

I got the bike in January so the idea of replacing cables and outes is not what I'd expect at this age and mileage.

navrig

Twostage wrote:

Might be worth making sure all the bits of the rear derailleur are lubed up ok and there isn't a load of crud stopping it from working properly.

Probably a good idea. I'll have a look at the lube points.

sungod

might also be worth checking that the mech hanger isn't bent