Sora 'double click' missing gears on rear casette

[MattDB]

Hi, I've got a sora 9 spd rear casette and I seem to be always adjusting my cable tension. Not just a little bit like I'd read but finding that I can't get it into bottom gear and having to tighten the tension quite a lot.
Anyway where I'm at now is that trying to shift down, one movement of the shifter makes two clicks and skips a gear - I assumed that this implies the cable is too tight but if I loosen to the point that it's only making a single click then it stops shifting up properly.

Am I being rubbish or might this imply some rear derailleur damage?

 

[screenman]

Start at the very beginning and check rear mech alignment.

 

[PaulSecteur]

Possible the cable needs replacing?

I have seen (and had) decent spec and brand of bike that have come with really cheap cables that need replacing well before i expected.

To test the theory, remove the inners an outers, clean, then spray gt85. If you get rusty bits coming out of the outers its time for replacement.

 

[MattDB]

Thanks - I'll replace the cables, I've been having to tighten an awful lot recently, like they stretch and stretch (or is this normal?)

 

[mrbikerboy73]

My bike developed this problem, unfortunately during a sportive. Frayed cable at the shifter end was the culprit. Cables do not stretch as such, the outers settle into the fittings on the frame and therefore require a slight adjustment but this is usually within the first 100 miles or so.

 

[MattDB]

Sorry didn't re-check this thread - maybe something else going on, I have to adjust my cable tension lots it seems.

 

[Justinslow]

Here's a tip that probably won't help in this situation but,
Always shift rear gears to the smallest cog when parking up for a period of time (days or weeks) as it takes the tension off the cable, and do the same with the front mech - shift to the smallest cog.
If you leave the bike on the biggest cogs you may find after a period of time the cables don't "release" properly and "stick" inside the outer cable, causing problems shifting.
This is particularly applicable to Mtb's where the cables are often put away dirty. The springs on the front and rear mech, particularly the rear are not all that strong and it doesn't take long for a sticky cable to mess with your shifting as the spring is too weak to move the sticky cable.
It's generally not a problem moving the cable the other way by tightening as the shift lever has greater leverage.
So to sum up - look after your cables and make sure they are free moving as it is essential for slick gear changes and no amount of fiddling with adjusters can set your gears up if the cables are sticky!

 

[MattDB]

Thanks, much appreciated!

 

[PpPete]

Not only the inners - but all the ends of the outers. I've seen cases where an outer has been mangled during installation and it's gradually destroying itself.

 

[sgl5gjr]

worth checking all suggestions...... but fit quality cables and outers.... it is such a shame when bike makers spec up their products and skimp on cables and the like...... I see so many so called Quality bikes with poor shifting in..... when I replace the cables with stainless and quality outers it transforms the bike into what it should have been out of the box..... I also get repeat custom as a result....