"lost" three gears!?!

[fast but dim]

I've "lost" 3 gears on my thorn audax.

It's 9sp ultegra, and on the way home from work I noticed the derailleur no longer reaches the three lowest gears on the cassette.

There are still nine clicks, but the first three don't pull any cable. If i pull the cable by hand on the down tube the derailleur shifts.

If I remove the slack and clamp the cable tighter at the rear mech, i can access the lower geared end of the cassette, but lose the three higher sprockets.

I am bewildered. Everything was working fine...A little play in the whole system, but ok.

The shifters are old 9sp, and get lubed with gt45 and spray grease as recommended here.

The cables are visually ok, but at least 3 years old.

I've ordered some eBay Clark's cables (another recommendation from here) as my first solution...

Am i missing something obvious?

Thanks FBD

[Gattonero]

Check if the gear wire is not frayed inside the shifter.
You can easily spot by dropping all the gears, when in top gear you will have the gear wire slack and moving off the gear outer from the shifter you may notice the cable frayed.
Or perhaps just cable slack, but Shimano shifters can chew the gear wires, so is not a bad idea to replace them for peace of mind.

[Brucey]

I agree it is probably a cable issue; it is quite possible that a stray cable strand may be lodged in the shifter and is causing troubles; removing such can be a right PITA.

Test #1 is to unhook the gear cable (eg at a slotted stop) and to manually apply cable tension near the shifter whilst working it. You will soon see if the shifter is paying out cable with each click or not, or if the cable is binding in the housing etc.

Three years is a very long life for a gear cable in a regularly used shimano STI. Some folk can't run them six months before they are in danger of fraying them.

BTW when you are fixing this fault you should feel happy (and maybe a bit smug too if you like) that you don't have stupid gear cables that run under the bar tape; IME it takes at least twice as long to sort those out...

cheers

[fast but dim]

Thanks...You've both confirmed what I thought.

Now...do I lube the gear cable on install? I know some do.
If so, what's the best way?

[fast but dim]

Correct diagnosis. The cable was very frayed!

Changed, lubed as instructed and working perfectly. I've done both sides, but the lh cable was perfect.

New cables will be an annual thing from now on!