This is kind of a combination mechanical/physiological problem, but I've been noticing lately that my right hand thumb has been pained by the action of switching gears at the front. It could just be that I'm getting old :\ I have to take my hand back off the bars a bit and push the lever with a straight thumb, or it's just all pain and no go. Clearly the cable could do with a service, but I'm not convinced that that is the problem.

Anyone experienced anything like this?

I've even considered getting electric shifters, but I don't know whether that would be worth the hassle.

Well, first of all you referred to the front derailleur cable but also to your right hand. It's one or the other. The front can be more of a stress, as most people are right handed and the front shift often requires quite a long stroke as well as strength. I had problems on a very hilly two days in Italy with my left hand, though it was more overall, as I have brifters.

Secondly, why do you not just check the shift cable? Whether you are having pain or not, if it's difficult to move it with the lever it probably needs attention. On most bikes it is fairly easy to free the housing from the stops so that you can check for friction and corrosion. But we need to know first whether it is indeed the front derailleur and the model and year of your bike and shifters.

pilate7004, We need more info. Style of shifters primarily.

While which lever controls which brake can be reversed, the front derailleur is a left hand task. It reads as the cable is sticking within the housing, an integrated shifter needs cleaning or too acute of a bend in the routing.

Brad

"Secondly, why do you not just check the shift cable?"

Agree totally. Shift cables are relatively inexpensive and easy to fit. Properly installing high-quality die-drawn stainless inner wires and lined outer housings can hardly fail to improve your shifting. If you still have problems you will at least know that the cables are not contributing to it.

Some details of your bike and drivetrain are needed for us to be of any real assistance.

IME, the biggest single cause of hard shifting is excess chain tension during the shift, which is easy enough to correct.

The second biggest cause is a tight outer limit, or poor trim which makes you force the lever to overcome.

It's easy enough to check the action of the FD itself, so start there and work your way backward to the lever and your thumb.

Either hang the bike (or have someone hold it up) so you can turn the pedals, or slip the chain off the chainring and pull it back from the FD. Then work the FD by drawing the wire away from the downtube. It should move freely with little force.

Next, reposition the chain, and shift back and forth pulling the wire the same way. It should shift crisply and not need excess tension to complete the shift. There should be a bit of over-travel possible beyond where the shift happens which you'll find if you work slowly. If you do need high force to complete the shift, or if there's zero travel, back out the high limit a hair (1/4 turn), double check that the chain doesn't overshift and dump to the outside of the chainring. Ideally you want as much over travel as possible without any risk of overshifting as possible.

Now check shifting via lever, You want to make sure the trim is such that the chain doesn't rub the cage when coming from the outer rear sprocket and as many others as possible working inward.

If all is spot on, and it does shift easily, then it's possible that your problem id biological. I rarely have any issues, but I sometimes have similar left thumb problems riding my thumbshifter commuter bike when it's cold or rainy. The combination of slippery lever, gloves, and cold hands seems to make it much harder than normal to upshift the FD.

Yes, replace cables first since they are super inexpensive. That is the most common problem I see. If not, it is usually bad set-up (like FBinNY said, trim too tight on outer limit). Try those two things first since they are inexpensive and easy. Another thing to look at is the angle of the shifter. It might be that is is angled too high or low causing unnecessary strain on your hands. That is also a very easy adjustment and could make a world of difference.

IME, cables are rarely the issue in cases like these, though a worn housing liner might be. In any cases, I'm very old school (spelled C-h-e-a-p), and always start with a proper diagnosis before spending one cent. It's easy enough to confirm whether the cable runs smoothly or not, and carry that all the way back to the lever.

If the cable is binding, the lever will be stiff through the range of motion, but if the cable is OK, and the limit or trim is the issue, the lever will move freely until the end, where it'll suddenly get stiffer.

In any case, if you replace the cable, replace the housing since that'll be the actual cause of high friction.