New wheel/cassette. 11t ring skipping.

moyesie

I've just installed a new pair of Fulcrum Racing 7's on my winter bike along with an 11-28 cassette which replaced an 11-25. I've also replaced the inner and outer cables.

With the new R7's being 11 speed compatible I had to install an extra spacer on the free hub to ensure the cassette didn't wiggle about, this was confirmed as ok by LBS.

I've set the indexing up and everything seems ok apart from in the lowest 11t cog when it's constantly making a noise as if it wants to move up the block, there is also a 'sticky' sensation when moving through the derailleur as if the chain link is stiff (this doesn't appear to be the case), this is not evident in any other gear.

A further complication is that on a quick 'up and down the street' test ride the chain is slipping quite dramatically; even without any real pressure being applied!

At a loss as to what the issue could be.

Help!

trailflow

First try aligning the rear derailleur's upper jockey wheel with the outer edge of the 11t cog.

Then try refitting the cassette and make sure all the cogs and lockring are seated correctly.
Then check the rear derailleur hanger is not bent and is screwed into the frame properly.
Then check the rear derailleur fixing bolt is tight.
Then check the rear derailleur cable is clamped correctly also.
Then make sure all the cable ferrules are fitted into the frame, and make sure there are no burrs on the cable outers causing unwanted friction.
If you have a plastic cable guide under the bottom bracket make sure it is secure and not moving around.

You could also try replacing the new 11t cog with the old 11t cog.

gethinceri

I had exactly the same with the exact same changes. BUT, have you replaced the chain? Any road up, I just re-indexed 3 or 4 times and then I was sorted.

Manc33

I think 11t "just do". It seems that way to me.

Older cassettes used to have a lot more square teeth, it could never slip. Compare those old 6 speed cassettes to the ones now with all cut edges and stuff, its hardly any surprise it skips, but of course it changes up and down the cassette better. :roll:

keezx

Wonder why anybody in the world would need an 11T anyway on a winterbike......

jgsi

What chain have you fitted - with a quicklink?
I use 11t or 12t , but have had issues with KMC , Wipperman either fitted the wrong way about or just too stiff and had to be binned as a bad 'un
Symptoms are just this , skipping on the smallest cog.

(.. why do some people feel the need to add superficial comments in this part of the forum?)

moyesie

Thanks for the replies

I've had a further play around and it happens without any gear tension (cable disconnected) so I'm ruling out a friction issue.

The 'skipping' happens just as the chain leaves the upper jockey and moves onto the cassette; this happens approx 5-6 over the length of the chain, I've checked for stiff links and they appear fine.

I've also:

Reseated the cassette and tightened locking.

Ensured jockey wheels are correct/tight.

Adjusted limit screw on the fly.

Would a bent hanger only affect the 11t?

Bar Shaker

Have you replaced the chain? I'm assuming so if you have gone from 25 to 28 maximum cog size as you would need a slightly longer chain. Check the chain isn't now too long as this will decrease the tension that the cage puts onto it and make stop the chain being pulled into the 11t cog teeth as it comes off the jockey wheel.

On the 11t cog, the cage should still have more travel to go before it is all the way back.

keef66

Are you definitely using an 11t lockring to secure the cassette? I know for Shimano 10 speed stuff a 12t lockring will foul the chain if used with an 11t sprocket.

If it's Campag, or Shimano 11 speed, I have no idea.

moyesie

I assume it's the correct lock ring as it came with the cassette

On a hunch I'd installed the jockey wheels I took them off but it turns out they were fitted correctly; I did however swap the retaining bolts and this appears to have fixed the issue. Whether that is down the bolts pushing the jockey wheel marginally out of alignment or I'd originally installed them slightly off I really can't tell!

I do however have another issue

When taking the bike for an 'up and down the street' test ride when I put any sort of pressure down the chain makes a horrendous noise and skips quite dramatically, the noise sounds like a loud band and not the skipping is quite violent.

All signs do point towards this particular chain being a bit of a duffer.

Manc33

moyesie wrote:

All signs do point towards this particular chain being a bit of a duffer.

How many miles does the chain have on it?

I always replace a cassette and chain together, that way they wear together.

Old chain on new cassette = slip.
New chain on old cassette = slip.

It can't be the freewheel if it is only the 11t skipping. The chain barely even wraps around an 11t sprocket. On a worn chain it definitely will slip. If they wear together you might get lucky lol. The 11t is a necessary evil. :evil:

If your chain is worn, the cassette you took off is less likely to skip than a new cassette.

StillGoing

You haven't by any chance changed your chain rings recently have you and put the inner ring on the wrong way around? Chain slipping on certain gears on the cassette and sometimes freewheeling when changing down on the front are typical symptoms.