fishugly

It's a Shimano Deore LX derailleur. It was shifting ok until I changed the cable and started dinking with adjustments trying to make it shift better. For a while, it would not even shift, then, after watching many how-to videos and much trial, error and frustration, I got it shifting decently. I have never tried adjusting one of these things before so I'm not even sure what it was that made it start shifting ok again.

It shifts into the largest sprocket but if I'm not paying attention, and holding the lever in far for an extra bit, it will go up to that largest sprocket then slip right back down to the smaller one.

After all the time it took me to get it to this point, I'm hesitant to try anything in fear screwing it up again. It's workable now but I know it could shift better.

Any simple solutions?

reshp1

You usually do have to hold the lever all the way until the shift is complete for the front ring, it's not as smooth as the rear just by virtue of having to shift the loaded side of the chain and the bigger gap both between the rings and in ring diameters.

Check your clearance from the derailler cage to the largest ring. It should pass within less than 2mm of the teeth. Then check alignment so the cage is in the same plane as the rings.
https://www.parktool.com/blog/repair-...ur-adjustments

EDIT: Just saw you changed cables. Are you sure you have adequate cable tension? You should be hitting your limit screw when throwing the lever all the way to shift from small to big ring.

fishugly

No...I'm not sure of anything, actually. This is all so foreign to me right now. I will tighten the tension a bit to see if that helps though.

The clearance as you mentioned above was originally taller than recommended so I lowered it...and that's when the troubles began. As much time as I put into it before getting it to shift again, I'm gunshy to mess with that aspect now. Maybe it would be a little easier now though....

Thanks for your reply!

reshp1

Hmm, it's kinda sounding like cable tension. When you lowered it (if it's a bottom pull cable), you would have reduced the cable tension, i.e. decreased the distance from the derailler to the cable stop. So you'll need to take up that distance by backing out the barrel adjuster (counter-clockwise) to compensate.

fishugly

Thanks. I'll dink around with it a bit more.

JanMM

Either needs a hair more cable tension or the high limit needs to be moved out just a hair?

Or, perhaps, if your derailleur has a little nub at the fixing point and if you routed the cable under the nub, then you need to release the cable and re-route it on top of the little nub.

Happened to me this summer when I replaced the cable and couldn't figure out why it wouldn't shift well to the big ring.
Some Shimano and Microshift FD's have the little nub.

fishugly

Not sure what the "little nub" is but I did have the cable routed one way and it wouldn't shift at all. Once I rerouted the cable, it started shifting......at least that's how I recall it. I fiddled around with various things for so long, it could be that I can't remember. Any way, thanks!

JanMM

Here's a pic of an FD with the little nub (must be some other name for it) to the left of the fixing nut.

If the cable is routed below, not quite enough cable is pulled.

fishugly

Ah, ok. I'll check it out. Thanks!