Shimano 105 11 speed Indexing

[Shearwater Missile]

I thought that I`d get my summer bike ready and gave it a check over yesterday. I noticed that the indexing had gone out of adjustment, since putting the bike away last autumn. I usually put it away with the chain on the 11 tooth sprocket, thus taking the tension off, but this time I`d left it in the middle of the cassette. I know that cables don`t stretch but somewhere along it`s route it must change. Has anyone encountered this or the reason ? Oddly enough it only happens on the 105 5800 bike, both my other bikes, Sora and Tiagra don`t suffer if they are left for any time. I don`t think it is wear as it has always done it and cables have been changed. It`s no big deal but I`d just like to know the reason. Suggestions on a postcard please !

 

[88robb]

Most likely the cable is snagging slightly inside the housing. When you leave it bent in one position for months (middle of cassette), the housing liner creates a small memory grip on the cable. When you shift again, it releases unevenly, throwing the indexing off.

The 5800 shifters also have a tighter cable bend than your Sora/Tiagra bikes, making them more sensitive to this.

 

[N0bodyOfTheGoat]

Something to look out for on 5800 era brifters (505), is the white guide inside the hoods being worn dramatically by the gear cables.

I've had these spares (left and right specific) saved in my bookmarks for years, but I've yet to buy a spare set for my 2016 Cube road bike that came with 5800, ~£2 each.
https://www.sjscycles.co.uk/gear-spares/shimano-strs505-sl-cable-guide-a-left-hand-y03m75000/
https://www.sjscycles.co.uk/gear-spares/shimano-strs505-sl-cable-guide-a-right-hand-y03n75000/

 

[fossyant]

Get some new SP41 Opti slick cables and be done with it. They make a huge difference. I put decent clables on my 10 speed 105 CX bike, but they only lasted the year before shifts weren't precise enough. Switched to Opti-slick and it's perfect.

 

[Shearwater Missile]

Something to look out for on 5800 era brifters (505), is the white guide inside the hoods being worn dramatically by the gear cables.

I've had these spares (left and right specific) saved in my bookmarks for years, but I've yet to buy a spare set for my 2016 Cube road bike that came with 5800, ~£2 each.
https://www.sjscycles.co.uk/gear-spares/shimano-strs505-sl-cable-guide-a-left-hand-y03m75000/
https://www.sjscycles.co.uk/gear-spares/shimano-strs505-sl-cable-guide-a-right-hand-y03n75000/

That sounds like a plan, thanks for that

 

[Shearwater Missile]

Most likely the cable is snagging slightly inside the housing. When you leave it bent in one position for months (middle of cassette), the housing liner creates a small memory grip on the cable. When you shift again, it releases unevenly, throwing the indexing off.

The 5800 shifters also have a tighter cable bend than your Sora/Tiagra bikes, making them more sensitive to this.

That sounds feasible too.

Thank you Fossyant as well. I think it will be a belts and braces approach.