Are my shifters worn out, or just need adjustment?

I've got a bike with some 7 year old Shimano RX-100 STI shifters. (RX-100 = Tiagra)

When I try to upshift, often the lever will just go up farther than it should and nothing happens (it goes up as far as it would if I was downshifting, and there is less tension (resistance) than there is when it works right).

This happens with both shifters. Do I need new ones or do i just need to make some adjustments?

-miller

I think it might be time to leave them to rest, but probally best to take it a bike shop and see what they think. ( go to a reliable one, not one that says your bike is stuffed when all you have is a flat tire.)

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http://www.goldstars.4t.com/

Had this problem on a stx mtb shifter and an ultegra - all they needed was cleaning and lubing .
Shimano doesn´t usually develop partial failiers that come and go they just break and stay broken , unlike campy that can gradually fail ( and be rebuilt )

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' too old to rock 'n' roll : too young to die '

Yeah, what el Inglés said would be the first thing I'd check.

Maybe blast some lubricant/solvent into the works. GT-85 or WD-40...

Then I'd check the cables and housings.

Strip them down and give the cables a good wipe and the housings a dose of the good 'ole GT-85 (or WD-40).

I used to work in a bike shop in the early 90s and this was a simple strategy for putting smiles back onto some customers faces.

Well I saw another thread on this forum, Titled "Cleaning and lubing STI shifters" or something like that. Most everyone that commented said it is a bad idea to to this, so I'm pretty hesitant to. The last thing I want to do is make it worse.