Chain Slipping

[BrynCP]

Today my chain started slipping in the 5th and 6th cog (counting from large to small) on my 10 speed 105. All others are fine. Last time this happened something went really wrong and my derailleur ripped off into the spokes.

It literally just started half way through a 35 mile ride today. There was a bad, clunky gear change sometime before it started (this wasn't my fault, e.g. a late change, but it sounded horrendous).

My chain is clean and lubricated, done 2000 miles and isn't even showing 0.75% stretch on the tool.

My cassette (105-5700) has done 10250 miles, but doesn't look worn. It's had 4 other chains, always replaced before 1% stretch. Those two cogs are probably the most used.

The cable is moving freely and clean, and the derailleur looks aligned fine.

Anything else I am missing here? I'll try re-indexing, but I don't have much hope being all the other cogs higher and lower shift fine.

 

[Kajjal]

Most likely you need a new cassette, as i am guessing from your post you are experienced at bike maintenance. Best to buy a new chain at the same time.

 

[davidphilips]

as kajjal said most likely worn cassette/chain just check derailleur top wheel for side movement before buying anything as a worn bearing in derailleur wheel/wheels can cause all sorts of less than wonderful shifting, just gently pull derailleur wheel side to side no need to remove chain if it moves side to side then it needs renewed.

 

[huwsparky]

Most likely you need a new cassette, as i am guessing from your post you are experienced at bike maintenance. Best to buy a new chain at the same time.

That's what I would do first off as well provided I couldn't see anything obviously wrong.

 

[ChrisEyles]

I'd agree the cassette is probably the culprit, 10,000 miles is a fair old distance to have put on it. Just possible you may have a stiff link in the chain making matters worse? Though I'd expect that to behave the same in all sprockets so probably not.

 

[BrynCP]

Thanks. I'll check the derailleur. It's only got 2000 miles on it so hopefully not worn!

If not, I'll go down the new cassette route. Oh joy getting that off (took me an hour last time and I didn't have to mind about wrecking any spokes through carelessness as the wheel was for the bin).

 

[Pat "5mph"]

Oh joy getting that off (took me an hour last time and I didn't have to mind about wrecking any spokes through carelessness as the wheel was for the bin).

How so?
Get a cassette tool with an incorporated handle, it's easy then, 2 minutes it's out.
If I can do it, be sure anybody can!

 

[BrynCP]

How so?
Get a cassette tool with an incorporated handle, it's easy then, 2 minutes it's out.
If I can do it, be sure anybody can!

I have a cassette tool and a separate adjustable wrench. So holding the chain whip in one hand, and trying to hold the cassette tool/wrench in the other and getting as much force as possible led to all sorts of issues - by the time I'd done that, and then fitted a gatorskin tyre, I had sore hands. I'd tried some of the tips of using the QR to keep cassette tool in place but it was either too short or didn't fit; can't remember now.

Almost as much fun as removing my bottom bracket.

 

[Ajax Bay]

Well done on getting 10,000+ miles from your cassette - much better than average, I suggest, and a credit to your cleaning and 'chainging' regime.
The 5 and 6 sprockets will be among the most used so not surprising they're the ones kicking up a fuss. New chain with the new cassette. You can put the current one back on to replace the new one, in 2500 miles, say, once it gets to 0.75% length gain and get the remainder of its life from it. Don't tighten the lockring quite so hard this time. Half a dozen clicks on it is surely sufficient, as opposed to trying for the full 40Nm.

 

[BrynCP]

Don't tighten the lockring quite so hard this time. Half a dozen clicks on it is surely sufficient, as opposed to trying for the full 40Nm.

It may be slightly easier this time as I put the cassette on last when I changed wheels, at which time it was probably at the full 40Nm as come out of the factory or shop.

 

[Pat "5mph"]

I have a cassette tool and a separate adjustable wrench. So holding the chain whip in one hand, and trying to hold the cassette tool/wrench in the other and getting as much force as possible led to all sorts of issues

Get the tool with the handle, much easier, honest!

I'd tried some of the tips of using the QR to keep cassette tool in place but it was either too short or didn't fit; can't remember now.

I have tried this also, before I bought the cassette tool with handle ... it worked no bother too

Half a dozen clicks on it is surely sufficient, as opposed to trying for the full 40Nm.

I know you are one of the most egregious bike mechanics on here but I have recently experimented with my new high value torque wrench (cannae be bothered to find the thread now) and 40Nm was 6 clicks

 

[sgl5gjr]

Cassette is fubar as others have said...... we have in the workshop the B'Twin chain whip...which is a fab bit of kit, no chain on it to slip... it fits in teeth of the smallest cog.... removal tool in the hole and undo...simple...no slipping and no problems.... also... 10k from a cassette.... you clearly don't hurt your bike...

 

[BrynCP]

Maybe it's my 106 average cadence giving the cassette an easy ride.

 

[Daddy Pig]

Do yourself a favour and get a kmc chain rather than that shimano rubbish...

 

[BrynCP]

I always fit KMC X10-93s but in this instance it was the bike shop who put the last chain on and they put a Shimano one on.