Argh! A minor shop annoyance

[Owlie]

I'd do it myself, except that I'm one of those people who needs to be shown mechanical things at least once. Then I can do it from written instructions. I've made it up the hill in my big chain ring. Only thing was that it wasn't this hot... No shame if that's the only bit I need to walk, right?

[Crankin]

Ah, have someone drive you there?
Or, put your helmet and shoes in a bag and go.

[OakLeaf]

I'd do it myself, except that I'm one of those people who needs to be shown mechanical things at least once. Then I can do it from written instructions.

I hear ya there. I'm such an abstract thinker that it's almost comical when I try to translate a page in a service manual to something real that I'm working on. I'll look to the page ... to the thing ... back to the page ... back to the thing ... back to the page ... and if I'm lucky, after six or seven times they'll start to resemble each other enough for me to understand what I'm supposed to be doing.

But I'll bet there are YouTube videos - would that help? There are videos on all kinds of bike service ... Let me check, BRB.


*********


wait, wait, if it won't shift DOWN, it's unlikely to be a cable adjustment. Cables don't get tight all by themselves, and every front derailleur I'm aware of is "low normal," meaning that if you have no tension on the cable, the derailleur will go to the smallest chainring.

I can think of two things could be causing this.

The most likely is that the cable's hanging up in its housing somewhere. When you operate your shifter, do you see slack cable hanging anywhere? If so, try a couple of drops of very light lube, and work it around (using gravity to help) to get it inside the housing. If this works, it should be only a temporary fix; if it's hanging up that badly, there's likely to be rust or a burr or maybe just a huge dirt wad somewhere, and you'll probably want to let your LBS replace the cables and housings.

The other thing (which is more rare, but happened to me twice when a LBS removed my front derailleur for service and then re-installed it without using a torque wrench, and then a friend helped me re-orient it and again didn't put a torque wrench on it ) is that the derailleur clamp could have moved on the frame. (If you have a braze-on FD, then never mind.) If the cable seems to be sliding smoothly through its whole travel, then this is a possibility and I can point you to a couple of videos.

I've never known a limiter screw to tighten up on its own at all, and it would have had to tighten up a LOT to deprive you of both your smaller chainrings. I wouldn't touch those. I've never had to touch a limiter screw after the initial setup of a FD and crankset.

[Owlie]

It'll shift (and shift as nicely as Sora can) it just makes awful griding noises in the small ring and less awful grinding noises in the middle. The chain's rubbing the derailleur cage in both, and I think I know enough to not ride in those rings if it's making those noises. Besides, it kind of robs pedal power.

I don't mind walking. Just a tiny bit annoying.

[OakLeaf]

Which side of the cage is it rubbing (inside or outside)? Not the little pin that connects the sides of the cages, surely?

[Owlie]

Which side of the cage is it rubbing (inside or outside)? Not the little pin that connects the sides of the cages, surely?

It's rubbing the outside. It's not constant in the middle, but it is on the small ring.

[ny biker]

If it's only a mile away, I would just walk.

[OakLeaf]

Okay. Sounds like the cable's just too loose, and chainline is contributing to the rub.

Still, it shouldn't be rubbing at all on the small ring (at least not when you're not cross-chaining), so your low limiter screw probably does need a little tweak.

Here's a video.

Look at your derailleur to make sure which is the high limit screw and which is low. They're not always the same as the one in the video, but they're normally marked H and L. If not, you can go to Shimano's website for the instructions for your particular derailleur, or just see which one moves the derailleur when you take all tension off the cable and mark that one as your Low limit screw. (If you tried the High limit screw first, count turns of your screwdriver - the Phillips head makes it easy to see a quarter or half turn - and make sure to put it back where you found it.)

If you have a barrel adjuster on the cable near the handlebars, then unless it's already at its limit, you won't need to loosen and re-position the cable in its clamp. Unscrew the adjuster (turn it in the direction that makes the housing longer - on my bike, it's away from me as I sit on the bike. You can watch the cable at the derailleur end and see what's going on as you turn the adjuster each way, if you're not sure) until there's no slack in the cable when it's on the smallest chainring.

If you don't have a barrel adjuster - or if it's already at its limit and you need to reposition the cable in its clamp - then pay attention to how it's routed and how the clamp sits before you loosen the clamp. On some derailleurs, unlike the one in the video that stays neat, the cable will just fly off, and/or you'll accidentally loosen the clamp a little too much and it comes off. So you want to know before you start how it all goes back together. Do make sure that you screw the barrel adjuster all the way back in before you reposition the cable (the guy in the video overlooks that at first and then goes back to it).

The guy in the video just pulls the cable taut using his fingers before tightening the clamp, but I find a pair of pliers handy here. Just to get a better grip on the cable, try not to crimp it.



Derailleur adjustments are so simple, and need to be done fairly regularly - sometimes on the road - so it's good to know how to do it yourself.

Plus, I've always found that learning to fix something of my own just feels tremendously empowering.

[Owlie]

Thanks, Oak. I'll fiddle with it a bit and see. She's due for a tune-up anyway, I think. (Last time it was done was this time last year!) I'll ask at the shop while I'm there if they could show me the basics of derailleur adjustments. They're not likely to be on whatever road I'm riding!