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Hello all,

The gear shifting on my commuter bike recently became a little random and, after checking chain wear, I realised it was time to replace it. However, the shifting is now worse than before and putting any significant load on the pedals in certain gears results in the chain slipping on the cassette (at least I think it's the cassette rather than chainrings). I've tinkered with the cable which is relatively new (8 months/2,500km) but that doesn't seem to have cured it. Is it likely to be the cassette that is worn and needs replaced or could it be something else? For reference, the cassette has never been replaced on this bike so has done 6,500km over the past 18 months including one Scottish winter. On a scale of 1 - 10 (10 being cleaning the bike after ever use and keeping it emaculate), I'd say the bike lives in a state of 5 or 6. 

Thanks in advance,

A

10 comments

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srchar [1627 posts] 1 month ago
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Yes, it is time for a new cassette. Your current one has worn with your old chain and the new chain does not mesh properly with the teeth. You will probably find that the "certain gears" where the chain slips most are your most commonly-used sprockets.

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Alessandro [185 posts] 1 month ago
1 like
srchar wrote:

Yes, it is time for a new cassette. Your current one has worn with your old chain and the new chain does not mesh properly with the teeth. You will probably find that the "certain gears" where the chain slips most are your most commonly-used sprockets.

Thanks for confirming. The slip is indeed on the more commonly used sprockets which had pushed me towards this theory prompting me to buy a new cassette last night but didn't want to waste time fitting if I was trying to fix something that's not broken. 

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bikeclips [30 posts] 1 month ago
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A word from the voice of painful experience... first ride after you change cassette and chain after a particularly worn chain, be careful standing out of the saddle and pushing hard on the pedals in-case you've also worn the chainring teeth. In that case, the new chain will no longer mesh neatly with the chainring and might slip, leaving you to plummet onto your top-tube with your most delicate parts! 

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Rose on a Rose [43 posts] 1 month ago
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bikeclips wrote:

A word from the voice of painful experience... first ride after you change cassette and chain after a particularly worn chain, be careful standing out of the saddle and pushing hard on the pedals in-case you've also worn the chainring teeth. In that case, the new chain will no longer mesh neatly with the chainring and might slip, leaving you to plummet onto your top-tube with your most delicate parts! 

Feeling your pain!
It took me a while and a twisted chain to realise that my outer chainring was overdue replacement.

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Alessandro [185 posts] 4 weeks ago
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Thanks for the tip! Changing a chain and cassette are currently within my bike maintenance skillset - how easy is it to replace worn chainrings?

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werics [11 posts] 4 weeks ago
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Alessandro wrote:

Thanks for the tip! Changing a chain and cassette are currently within my bike maintenance skillset - how easy is it to replace worn chainrings?

Ranges from easy to easier, except when it's nearly impossible. Depending on the style of bolt used, may need a chainring nut spanner (if one side has two flat notches instead of a hex head), and some cranks have to be pulled to swap the rings, though many do not. The nearly impossible comes into play if they're riveted on, which is usually only seen on very low-cost cranksets.

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Alessandro [185 posts] 4 weeks ago
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werics wrote:
Alessandro wrote:

Thanks for the tip! Changing a chain and cassette are currently within my bike maintenance skillset - how easy is it to replace worn chainrings?

Ranges from easy to easier, except when it's nearly impossible. Depending on the style of bolt used, may need a chainring nut spanner (if one side has two flat notches instead of a hex head), and some cranks have to be pulled to swap the rings, though many do not. The nearly impossible comes into play if they're riveted on, which is usually only seen on very low-cost cranksets.

I'd be replacing them on this bike:

https://www.evanscycles.com/cannondale-caad-optimo-105-disc-2017-road-bi...

My hope was that I'd be able to undo some screws, pop the old chainring over the cranks and then do the reverse with the new ring(s). 

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hawkinspeter [4258 posts] 4 weeks ago
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Alessandro wrote:
werics wrote:
Alessandro wrote:

Thanks for the tip! Changing a chain and cassette are currently within my bike maintenance skillset - how easy is it to replace worn chainrings?

Ranges from easy to easier, except when it's nearly impossible. Depending on the style of bolt used, may need a chainring nut spanner (if one side has two flat notches instead of a hex head), and some cranks have to be pulled to swap the rings, though many do not. The nearly impossible comes into play if they're riveted on, which is usually only seen on very low-cost cranksets.

I'd be replacing them on this bike:

https://www.evanscycles.com/cannondale-caad-optimo-105-disc-2017-road-bi...

My hope was that I'd be able to undo some screws, pop the old chainring over the cranks and then do the reverse with the new ring(s). 

You should be fine with that - looks like it's a FSA chainset which are easy to work on.

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Alessandro [185 posts] 4 weeks ago
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hawkinspeter wrote:
Alessandro wrote:
werics wrote:
Alessandro wrote:

Thanks for the tip! Changing a chain and cassette are currently within my bike maintenance skillset - how easy is it to replace worn chainrings?

Ranges from easy to easier, except when it's nearly impossible. Depending on the style of bolt used, may need a chainring nut spanner (if one side has two flat notches instead of a hex head), and some cranks have to be pulled to swap the rings, though many do not. The nearly impossible comes into play if they're riveted on, which is usually only seen on very low-cost cranksets.

I'd be replacing them on this bike:

https://www.evanscycles.com/cannondale-caad-optimo-105-disc-2017-road-bi...

My hope was that I'd be able to undo some screws, pop the old chainring over the cranks and then do the reverse with the new ring(s). 

You should be fine with that - looks like it's a FSA chainset which are easy to work on.

Great, thanks. I'll see how next week's commute goes with the new cassette and work out whether I need to replace the chainrings as well. 

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leaway2 [117 posts] 4 weeks ago
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Easy. Take a looks at
https://www.spacycles.co.uk/m2b0s210p0/Parts-and-Accessories/Components-...
I replaced my Cannondale synapse FSA chain ring with one of these (110 BCD IIRC) after damaging it after an unplanned dismount incident.