ZHVelo

So I got a flat yesterday and after fixing it, I was checking everything to see if it works. Turns out being on the low ring at the front and largest sprocket at the back and pedalling backwards makes an odd sound. Not that I would ever do that, especially in my lowest gear, but I was just wondering if this could possibly indicate the rear derailleur is not positioned 100% correctly? It is just the largest sprocket, moving one down and it is already smooth again. Pedalling normally there seem to be no issue at all.

Thanks,
ZHVelo

Trevtassie

Yep, probably a slight misalignment of the derailleur. Look up some Youtube videos how to set limit screws on a rear derailleur or have a look at the Park Tools videos.

ridelikeaturtle

Also double-check the wheel is aligned in the dropouts correct. Common issue.

ZHVelo

...should not have asked, only made it worse playing around with H and L screws lol.

I will see if I can fix if not I will have to pay (here services are ridiculously expensive).

ZHVelo

Update - so now I can shift gears again, they all come in quite easily (even the smallest sprocket, I really only ever use that downhill but here for some time I noticed it was harder to get into) and the original problem is solved (back pedalling no longer makes the chain jump), however, now the pedal motion just doesn't seem 'smooth'. Especially in the smallest sprocket but also the next 2-3, only really the 4th smallest does it start to feel 'smooth'. And hereby I mean it feels like when I turn the pedals it feels like they are held up. It doesn't feel like one smooth clean motion but more of a rr rr rr rr. Any ideas on that?

I hope I didn't bend something or whatever, as I said in the post above, for a while I think the chain was off the cassette even totally stuck.

Edit: So I loosened the B screw quite a bit (it could be that I tightened it earlier when I was getting frustrated and just trying things) and now the third smallest sprocket feels good, the 2nd smallest so la la and the smallest still kind of bad. But I think I can give the bike a spin and see how it is actually pedalling properly.

dsbrantjr

Since you have been "playing around" with your limit screws, I suggest that you make certain that you go back and ensure they are correctly set, so that you don't throw off your chain or have it shift into your rear spokes.

cyccommute 

As I tell my mechanics students, the Siren song of the limit screws have dashed many a bicycle mechanic upon the rocks of derailer adjustment. I often feel that the damned things should be ground off after the initial adjustment just to keep newbie mechanics from grabbing a screw driver! The limit screws do nothing for adjusting the derailer. They keep the derailer from shifting into the spokes...a bad thing...and from shifting into the frame...a less bad thing. That’s the last time they ever need to be adjusted!

To approach your problem...water under the bridge now but a good teaching moment...look at the last thing you did for the solution. If the bike was shifting fine before you removed the wheel and isn’t after you put it back, don’t pick up the screwdriver, Ulysses, but look at the wheel first. Ensure that it is in the dropouts evenly. Even reposition the wheel just in case.

If the problem persists, check the cable adjustment. Shift into high gear on the cassette and see if the cable is loose. It should be taut with a little “twang” but not super tight. Click through the gears and if the derailer hesitates to shift down (go to the larger cog), use the barrel adjuster to tighten the cable just a little. If it overshifts, use the same barrel adjuster to loosen the cable...again just a little.

If that doesn’t work, check to see if the derailer hanger is straight. Shift to a middle gear on the cassette and look at the derailer. From the cog on the cassette to the bottom jockey wheel, everything should be in a straight line. If it bends either inboard (most common) or outboard, look into straightening it. You can find a You Tube on how to do that.

As to when to check the limit screws, do that after you have checked the moon, stars, alignment of the Andromedan galaxy, tide charts, the last decade of the Dow/Jones, the amount of ozone above the South Pole, etc. In other words, the limit screws should be the last thing you check when your derailer is acting up. I will (almost) guarantee that the limit screws will not be the problem.

For trying to get yourself off the rocks of the limit screws you find yourself upon, go over to Park Tools and work through the guide on derailers. Once you got it all to working again, put the screwdriver on a high shelf and never touch it again! Stop up your ears, brave Ulysses!

ZHVelo

Thank you! That is a lovely reply and wise words to learn from