New chain, new cassette, new wheels & gears still jumpin

BigStu2

Hi guys, I have a 2009 Canonnodale with 105 shifters and rear deraileur. The standard wheels had a 105 cassette and the new wheels I've just fitted are Dura ace SL with an Ultegra cassette and chain.
The gears changed faultlessly before now they jump back and forwards on most gears.
I even disconected the rear derailuer cable to check that the rear mech was lined up correctly with the 11 tooth sprocket. It seems no mater what tension I have the gears jump, if I back the cable tension off then the gear change from no.11 to 12 doesn't happen (then you have to change twice to move the rear mech one gear) and if I adjust the cable so that the 12 toother is engaged then it starts to jump further up the cassette, tried fitting the 1mm spacer which resulted in even more problems, any one got any ideas :oops:

JohnnyAllez

Pretty sure the 10 speed cassette has to run with the 1mm spacer behind it, to start with. Once installed you can adjust your H and L screws to align with the cassette, although changing the wheels shouldn`t really have altered anything with the alignment. This really shouldn`t affect the "jumping" further up the cassette though, unless the cassette isn`t tight on the splines due to the spacer being missing?

Is the cable routed correctly at the rear mech end? It`s possible to get it the wrong way round at the cable clamp and this causes the problem you`ve got (people use this method to get other makes of cassette to work with Shimano shifters, where the sprocket spacing is slightly different to that of a Shimano cassette)

Wappygixer

Has the bike taken a knock and bent the mech hanger?

bornagainbiker

Hi, I had the same 'problem' after stripping and cleaning the whole bike couldn't get ALL the gears to index.
Asked at a couple of bike shops who suggested worn cassette ( after less than 1000 miles?!)
In the end I finally sussed out the cable needed to be set up WAY tighter than I had thought.

Hope this helps

BigStu2

bornagainbiker wrote:

Hi, I had the same 'problem' after stripping and cleaning the whole bike couldn't get ALL the gears to index.
Asked at a couple of bike shops who suggested worn cassette ( after less than 1000 miles?!)
In the end I finally sussed out the cable needed to be set up WAY tighter than I had thought.

Hope this helps

I'm thinking the same thing about the cable, its the original, still only just over 1200km old, not much for a road bike but I have gone a few mm past where it was screwed down before, I think it just needs to be ridden a few k's to bed it in then it'll be all smiles, the new wheels are a blast though

nferrar

Aye worth pulling out the cable and cleaning the outer + inner (or replacing them if you can't be bothered with that), stickiness in the cabling can cause jumping as it messes with the tension on the cable. That or check for a bent mech hanger like someone above posted.

ride_whenever

gunky cables or shifters.

ADIHEAD

Watch this video, if it doesn't work then change the cable - they'll be another video telling you how to do that also!

http://www.youtube.com/watch?v=SkzvfCaIbyQ

ADIHEAD

Oh yeh you should easily know if you need the 1mm spacer as the lockring won't tighten correctly if that's the case. I needed it with my WH7850's, also with an Ultegra cassette.