So I just bought a new (used s-works Roubaix) off ebay. Ultegra grouppo. After putting it together and dialing it in for initial fit I took it out for a spin. It started ghost shifting and I couldn't smooth it out with the tensioner on the road so I took it home and put it on my stand. I disconnected the cable and set the limiter screws and then got it working nice on the small end of the casset, nice cable tension, good stop in 10th gear. As I started working up towards first it started getting noisy and the a little glitchy and then by the time I got to the top (1st gear) it would ghost shift.


To get it to work nice up on top I had to dial the tensioner in the opposit direction that I had to go on the bottom end. Once it got sweet in 1st gear as I would then work it down towards ten, the same thing would happen. Started getting noisy in the middle ,,, as I got closer to 10th it got glitchy and eventually when if would finally get into 10th it would ghost shift again and I would then have to feather it in the opposite direction of the answer on the other end to smooth it out.

I bought a new chain because the old one was right at the end of it's life. It didn't change anything. I lubed my cable and brifter and still have same problem. I'm pickeled between the top and bottom end. nI took it to my LBS and had them check to see if my hanger was bent and it was fine. The head mech was gone and the guy that was on shift tried to fix my problem and he couldn't find an answer either.

Lastly, the bike came with 6700 brifters and a 6600 rear derailure. Could that be the issue even though there both 10 speed?

I don't know what to do and hoped someone else could advise before I have to start buying new parts. I guess I could try a different wheelset,,, or put a different cassett on it before I start buying new parts.

None of the parts have any scuffs to indicate any drops/wrecks ect

Thanks

Ryan

What size frame and what year? I want to look at the geometry charts, short chain stays can contribute to ghost shift issues. I had a tri bike with that issue.

I missed in the intro above as I have bikes almost the same. My problem is on a 61cm S-works Tarmac 2010 not on my Roubaix.!!! Sorry for any confusion.

It almost seems like my brifter thinks the cassett is a bit wider than it is

Geometry doesn't appear to be an issue, is the rear cassette possibly not original (like maybe a sram cassette having issues with a shimano setup?)

No, it's a shimano cassett and I checked it at the bike shop with a piece of new chain and it's not worn past specs either

Is the cable attached to the cable stop correctly on the RD?

If they're not mounted right, it can subtly change the throw of the dérailleur.

Whenever I encounter a bike with a rear shifting problem that doesn't respond to normal tuneing, the first thing that I do is to check the derailleur hanger alignment. Most of the time - that's it.

9 and 10-speed cassettes are quite sensitive to less than perfect hanger alignment. A bike that has recently been shipped, especially without a factory packing job is suspect. If it was my bike I'd take it to a shop and have them check the alignment with their gauge. That's about a $15.00 or $20.00 service. Even if it turns out to be spot-on, it's worth it to rule out hanger alignment as the source of your problem.

Unfortunately, this appears to have been ruled out as the cause already...

"The head mechanic was gone." I have my doubts.

Haha - good point....

You need to ensure the RD is shifting to each cog properly by looking at it shift from behind, with no chain in the way. If the cogs line up with the jockey wheel but it won't shift the chain, you could try letting out the B screw to get the jockey wheel closer, or maybe your cogs are worn (since you have a fresh chain, it's not that). Otherwise, your RD isn't indexing properly for some reason.

And the rest of the time, it's an incorrectly clamped cable. The only other thing that could cause the derailleur to shift further than it should is shifter/RD/cog spacing mismatch. If it's not shifting as far as it should, it might also be damaged cable housing.

BTW, any Shimano RD should work with that shifter and the correct 3.95mm 10s cog spacing, except 8s Dura Ace and MTB stuff called Dynasys or something (10s MTB AFAIK).