Bicycle Mechanics - Do STI gear leavers wear out.Problem with the rea rone

These are 105 10 speed with near 20,000 miles on them.The rear one seems slacker than when I first got it,and seems not to move cogs sharply,or engage in the gear moving down when I click the lever once.Shifting up is no problem.All the adjustments are correct,cable tight,and derailleur set correctly.What do you think it is.Is my right hand lever on it's way out?

What do you think it is.Is my right hand lever on it's way out?
Yes. After high use or a long time of storage, they stop working well. Take all the cables out, unwrap your bar, undo the bolt holding it to the bar, slide it off. Then spray some penetrating oil into the shifting mechanism.

20,000 miles is not very long. I have 3 times as much miles on mine and they still work fine. Cables can go bad much sooner, even if they appear tight. If you haven't replaced your cables and housing in the last 5000 miles, try that first. Also clean the cable guide underneath your bottom bracket.

Sluggish shifting to smaller cogs (this goes for any derailleur system that isn't low-normal; 99.99%): almost certainly excess cable friction. Possibly damaged or incorrect length housing making it worse.

Ok,thanks I will check through it later on.I replaced the cable about 2000 miles ago,so hopefully it could be just cable slack

Checked the front housing first on the front derailleur.Seems like it has seized up.Knowing how to cut it properly might help without making the ends frayed.Will let you know if the back if rined too

Don't forget the small rear cable housing. It can cause problems.

Ok,thanks I will check through it later on.I replaced the cable about 2000 miles ago,so hopefully it could be just cable slack

But did you replace the housings? They are just as important as the cables.
Try hosing out the shifters with WD40. No need to remove the shifters unless you have tried a WD flush and new cables and housings.

Yes,the rear back housing near the derailleur was changed,the other ran smooth at the time,so maybe be they need checking again.I'm gonna check.Tried wd40 but this one was too rusted.Well it looks like a trip to the bike store.I might be able to afford 2.50 for a housing
Thanks

These are 105 10 speed with near 20,000 miles on them.The rear one seems slacker than when I first got it,and seems not to move cogs sharply,or engage in the gear moving down when I click the lever once.Shifting up is no problem.All the adjustments are correct,cable tight,and derailleur set correctly.What do you think it is.Is my right hand lever on it's way out?
Buy a vintage Dura Ace.

Still screwed.new thread posted