shifter skipping a cog?
 

I wasn't happy with my shifting from my stem shifters, so I switched to downtube shifters (105 indexed 6 spd shifters supposedly NOS with crappy Tourney derailleurs and 6 spd freewheel). Actually the levers are on Kelly Take Off's because I'm not gonna reach down to the downtube regularly.

I'm happy with the friction shifting up front (adjusted with park tools big blue book instructions) but have an odd issue with the rear. The shifting skips the second smallest cog on the freewheel. There's not a click that it's missing indicating bad indexing. The first slot has the smallest cog, the second slot gets the 3rd smallest cog, third click gets 4th smallest, 4th click gets 2nd biggest, and 5th click gets the biggest cog.

Anybody have an obvious explanation as to why this might be?

I have more housing than I need between the shifters and the first cable stop (and I need to take care of that), but I don't think that is the problem. Or could it be?

thanks for any ideas.

curiouser and curiouser. this shifting of 1, 3, 4, 5, 6 (with 1 being 14T and 6 being 28T) only happens when I'm on the smaller two (24T and 36T) chainrings. On the 46T chainring, the shifting goes 2,3,4,5,6 skipping the 14T cog. Does that imply a chainline issue? Alignment? I'd really like to be able to use my 46TX14T gear. That's one of the reasons I wanted to switch shifters (after location which was the biggie) as I could only get the 14T cog about one in 4 shifts with my stem shifters. the rest of the time it'd stay in the next cog up. I primarily ride in my largest chainring and cogs 2,3,4 (mainly 3) but would like the higher gearing for downhills and when I want to pretend I'm sprinting and the like. Any help would be appreciated.

My downtube six speed shifters are friction, not indexed, but I had a similar odd problem with it skipping the same cog. It seemed for a while that no matter how careful and subtle I was about nudging the lever, it skipped the same one going up and down. I propped up the bike where I could work on it and just kept turning the cranks and shifting up and down through the gears sequentially over and over again. It might have been an odd wear pattern in the derailler mechanisms that needed wear to smooth out, or a slight kink in the cable, or maybe a stiff chain, but after working through the gears and oiling a bunch it smoothed out and it's been buttah ever since.

hmmm, interesting. In your case was it skipping the same gear on all 3 rings?

since I put on new levers, I also put on new cables (the front seems a lot smoother/faster) as a result.

I'm not sure why I only get shifting on 5 clicks rather than all 6 (so probably not a limit screw thing?).

I dont think my hanger is bent. It looks pretty straight to the eye and aligned with the allen wrench (that I assume is straight).

Well huh. Now I'm skipping the 16T gear in all chainrings. The first post was just pedaling the bike with no resistance (holding it up by the seatpost) and the next was after low speed riding it around in the garage. Now after a commute in to work it shifts from 18t to 16t for maybe half a revolution, and then down into the 14t. I wonder if it's an indexing thing after all.

Is it possible I connected the cable with too much tension on it so it starts in a position halfway between the two gears and has a hard time choosing? I did use my 4th hand to tighten the cable as the first time I put it on it was too loose and had too much slack in the cable to do much shifting at all.

The jump from 46tx18t to 46tx14t is just too much of a jump as I really need that 46x16t. is it time for me to drop it off at a shop for a professional adjustment?

I do have to say though that shifting from the hoods is nice, though I occasionally was lifting my hand to try shifting from stem shifters that were no longer there. That'll go away with time.

Mine was skipping the second smallest cog in both the big and the small ring. Best of luck with diagnosing this. When I'm super stumped I revert to the No Time For Sergeants school of radio/derailleur repair. ;)
http://www.youtube.com/watch?v=U2fSw0ua5K0

well if I do something I'll let you know.

Aristotle, may not help you, but I found that in my case if I have my front derailleur as far toward the crank on the large chainring as possible, I hit gears 2-6 rather 1,3-6. Don't know if that means anything, but by changing the position of the ring, I can get the other gear. I wonder if I flip over from indexed to friction if I can get all 6 until I get the adjustment figured out so I can do it indexed. Don't understand why you can't with your friction gearing.

Well for me switching over to friction sure helped. I don't always get the 14T gear now, but I do always get the 16T which I use a lot more. I'd stayed away from doing that because I'd gotten the impression that indexed was so much better than friction, but I don't really see what all the fuss was. I'm kind of wishing I'd gotten the cheaper 7 spd indexed shifters and run them friction with my 6 gears and had room to upgrade to 7 eventually, rather than spending more for the NOS 6 spd which were harder to find.

I'd still like to fix the shifting so I can go back to indexed eventually, but this will work until I have time.

Still looking for suggestions why the derailleur would skip my 16T (go from 14t to 18t) without there being an empty indexed slot (ie only running as if it were a 5 speed with an empty indexed slot at the very end) if anyone has any.

Couple of things to check:

1. Make sure that you have all of the slack out of the shift cable. When you're in the littliest cog position the cable should feel just taut but not tensioned.

2. You mentioned a Tourney derailleur. Is that the direct mount type or do you have a derailleur hanger on your bike frame? Either way, shift into a gear combination that makes your derailleur arm point straight down. Now prop your bike up vertically against something and check out the derailleur arm from the rear. If it doesn't point straight down, gently bend it until it does.

My bet is one of the above will fix it.

Retro Grouch, thanks for the advice.

I think it might be a bit beyond taut and into tensioned. I just pulled it through by hand first (but apparently not hard) and left a lot of slack in the cable and it didn't shift right at all. So then I pulled it through with the 4th hand tool to make sure it was nice and tight (I did slightly have to move the derailleur inwards to get it in at first, but then I loosened it up just a touch so that wouldn't happen when I finally screwed down the pinch clamp). May have gone a bit too far in that.

Also, I think I have a bit too much housing as it crosses the centerline of the frame by maybe an inch or two on each side before going back to its own side (I don't know why/how I screwed that up when measuring). I wonder if that could be part of the problem.

The bike does have a derailleur hanger on it. I put an allen wrench flat up against the back of the hanger and it looked pretty flush to me so I didn't think the hanger was bent, but I'll try your suggestion. Didn't occur to me to check the derailleur arm.

it sound like there to much tension on the cable ,back it off some and it should work better.