Gears skipping after fitting new chain and cassette

[αdαmsκι]

Nienke's bike has a new chain (SRAM PC850) and a new cassette (8 speed SRAM PG 830), but the gears are skipping. This isn't autoshifting and it doesn't even seem to be caused by the rear mech attempting to autoshift, either. The jockey wheels on the rear mech have been cleaned and reassembled. It'll happen for a period of time & then vanish for a bit. Hints and tips for solving this problem? It seems to occur when the SRAM Powerlink, which came with the chain, reaches the rear mech, but if it is something in regard to the Powerlink then I don't know what I could do to solve the problem. Or it may be something else 

[GruB]

Aha, my problem.  Tiagra is made from cheese.  I've just ordered a new chain ring set to overcome this annoyance after already purchasing and installing my new chain and cassette.

[Jurek]

1/4 turn at a time, take up the gear cable slackness with the derailleur mounted adjuster. See if that makes a difference. It did with mine.

[vorsprung]

stiff link near the powerlink?

[Nienke]

Thanks for all the suggestions. We're pretty sure it's not a stiff link, and spent most of our commute this morning fiddling with the adjuster, but we'll try doing that some more. I'll try anything twice before getting a new chainring set... It's a bit tricky to sort out because it needs to be ridden for at least 100 m or so to figure out if the adjustments have actually made a difference, as the skipping doesn't occur all the time. Nothing seems amiss if we just turn the pedals by hand with the wheel off the floor.

[PhilO]

I've had this on my MTB in the past and cured it by fitting new jockey wheels.*

*This was on an all-shimano drivetrain. My experience of SRAM chains is that they skip no matter what you do with them, but I know many people swear by them. 

[fred the great]

Interestingly I had this on a new road bike. The shop gave me one those high faluting  lubricants which I was using. I checked alignment and for stiff links to no avail and in the end went back to my tried and trusted 3 in 1 oil.

And the problem was never seen again

I still have no idea what the problem was.

[cc93]

I had a similar problem with Mrs W's bike despite changing chain, cassette and chainrings.

Checked the frame and found the gear hanger was bent!

luckily it was a steel frame, so a bit of careful levering and all was well again.

[αdαmsκι]

I've had this on my MTB in the past and cured it by fitting new jockey wheels.

Hmm, an interesting idea.  Ribble are currently selling sets of jockey wheels pretty cheap, which is nice.  The ones I've linked to say they're for "suitable for 7/8 speed rear gear", so they'd work with an 8 speed Acera-X rear derailleur.  Right?

Checked the frame and found the gear hanger was bent!

Given that there was "an incident" not so very long ago this could be an unhappy possibility.

[MSeries]

The only time I have had a new chain slip or jump is when it was too long.  Not enough tension in the mech you see. Did you check this when fitting the new chain ?

[αdαmsκι]

The only time I have had a new chain slip or jump is when it was too long.  Not enough tension in the mech you see. Did you check this when fitting the new chain ?

To ensure the chain was the correct length I measured, by counting links, the new chain against the old chain.

[Nienke]

Checked the frame and found the gear hanger was bent!

Given that there was "an incident" not so very long ago this could be an unhappy possibility.

I think it's getting pretty close to an unhappy certainty. I just had a look and it definitely looks like it's at a bit of an angle (i.e. not straight down but slightly inwards).

Bugger.

[cc93]

Don't panic (yet)

Is it a steel frame? - can be re-bent easily

Is it an aluminium frame with a detachable gear hanger - unbolt and straighten or replace

No? - Ok now panic, sorry 

[αdαmsκι]

Don't panic (yet)

Is it a steel frame? - can be re-bent easily

Certainly the main frame is aluminum & I'm pretty sure the rear triangle is also made from aluminum

Is it an aluminum frame with a detachable gear hanger - unbolt and straighten or replace

Nope, it doesn't have a detachable gear hanger.

No? - Ok now panic

Yip, I'm panicing away.

Arrrrrrrrrrrrrrrrrggggggggggggggggggggggggggggggggggggggghhhhhhhhhhhhhhhhhhhhhhhhh

sorry

Not your fault & I already knew that already too so you aren't even the bearer of bad news.  But, still, arrrggggghhh

[cc93]

oh dear 

well, if the frames a write-off anyway you won't lose anything by carefully trying to bend it back?

It might work

[Nienke]

Ergh. Well we'll have a look later to make sure I'm not making things up and it's definitely bent. I do also think the hanger looks detachable (Adam has been looking at a same brand bike but maybe it's slightly different?) so we'll have to have a look to see if I'm making that up as well.

Then we panic. 

[Jurek]

A frame will not be made of mixed metals ie Steel and Aluminium - it'll be one or the other.
Any old magnet will tell you which material it is.
G'luck.
*looks around for fingers-crossed smiley*

[αdαmsκι]

A frame will not be made of mixed metals ie Steel and Aluminium - it'll be one or the other.
Any old magnet will tell you which material it is.
G'luck.
*looks around for fingers-crossed smiley*

I know the main triangle is frame is made of Al & so the hanger will be Al too.  Drat.

[Polar Bear]

What bike is it please? 

[Nienke]

A specialized sirrus. I think it's about 6 or 7 years old.

I found a bike bit on the Edinburgh bicycle cooperative website that suggests it's a gear hanger for an '01 or '02 sirrus, and looks remarkably like the bit that's on my bike, so there is some hope.

[Wendy]

Ooh, I'm sure my sirrus had a gear hanger.  Fingers crossed for you, Nienke.

[Polar Bear]

I'm pretty certain that a Specialized will have a removable mech hanger.  

Linky

And another...

Fingers crossed for you too  

[Nienke]

Yay! 

We removed the hanger from the bike and it is indeed removable as well as bent. We're off to get a new one and then fingers crossed that I'll be back on the bike later this evening!

[GruB]

Yay, we love a happy ending. 

[Polar Bear]

Get a spare...