Extra shift click in rear derailleur

[NhiTrac]

So, after eight-ish years of riding and mostly DIY servicing of my own bike, I have finally been stumped by my latest shifting woes.

Bike is a 10sp Ultegra and I recently changed cables, chains and more importantly, the rear cassette to from a 11-28 to a 12-30.

No matter how much I tune the damn thing, I'd either have a spare 'click' (shift) at the top of the biggest cog to get it down to the next one. Or a spare shift at the bottom of the small cog, to get it to shift up one... But not both at the same time, just one or the other depending on how much I turn the barrel adjusters.

Anyhow I just can't get it right.

Note, the chain is probably a link or two too long but I havent had the chance to grab some pins to shorten it - I dont imagine this being a factor though???

Any ideas before I throw in the towel and take her to the LBS?

Thanks gang

[Duck!]

Have you repladced the gear cable and outer casing? If the cable is fraying (a common problem with stainless steel cables as they age) or the outer casing is worn, the result is excess friction, which makes proper tuning impossible; you need too much tension to shift down the gears (to the larger sprockets), which is then too much to allow it to shift the other way, and then to shift up the gears (to smaller sprockets) you need to back it so far off for the derailleur spring to pull the cable through that it's too slack when you want to downshift.

It should also be pointed out that there are two subtly different versions of the 6700 Ultegra 10-sp. derailleur, excluding standard or longer cage forms. The pre-2012 original version is officially limited to a 28T large sprocket by its upper body geometry, but can in some cases be pushed to larger. The post-2012 version, known variously as 6700-A or 6701, has a revised lower link which kicks the top jockey wheel a bit lower to increase sprocket clearance, will fit up to a 32T sprocket. If you have a pre-'12 version, trying to make it work with the 30T could be causing it to "hang up" against the out-of-spec large sprocket, requiring overtensioning of the cable to get the derailleur to pull up to it, or excessive slackening of the cable to enable it to drop off the large gear. Either scenario will result in a double shift somewhere else in the cassette.

[NhiTrac]

Thanks mate - appreciate it.

Ok I think your last paragraph nailed it (I'm on pre '12 6700)

Outer sleeves replaced as well as I bought them as a kit.

Either scenario will result in a double shift somewhere else in the cassette.

Yep just had another go and got the top and bottoms to shift albeit not crisply, but then had to double shift near the centre cog.

Anyone need a near new 10sp 12-30

Thanks for your help Duck

[lone rider]

I'm running a 12-30 on 5700 with no probs, might be a subtle difference in derailleur's, dunno, but have a good play around with b tension screw before giving up completely.

[NhiTrac]

I'm running a 12-30 on 5700 with no probs, might be a subtle difference in derailleur's, dunno, but have a good play around with b tension screw before giving up completely.

Cheers but already gave up and bought an 11-28. She shifts crispy smooth now.

But yep I played around with all screws and barrel adjusters but no go.