# Rear cassette



## ScotiaLass (2 Jun 2015)

Okay, I have replaced the chain on the MTB but now it's skipping all over the place! 
I've been told I should have replaced the rear cassette as well. What should I replace it with?

The bike has a 'Sunrace 9 speed 11-34' on it. 
I want something a bit better. Suggestions please?


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## Rickshaw Phil (2 Jun 2015)

You should be able to replace it with any Shimano compatible cassette. Shimano (obviously) or SRAM would be my choice and both companies do 11-34 9 speeds in various grades of quality depending on how much you want to spend.


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## sittingbull (2 Jun 2015)

Assuming you wish to keep the same range of gear ratios I would go for a SRAM PG-950 11-34T


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## Mo1959 (2 Jun 2015)

ScotiaLass said:


> Okay, I have replaced the chain on the MTB but now it's skipping all over the place!
> I've been told I should have replaced the rear cassette as well. What should I replace it with?
> 
> The bike has a 'Sunrace 9 speed 11-34' on it.
> I want something a bit better. Suggestions please?


Not cheap and I'm not sure whether the quality is any better than Sunrace or not? Maybe someone else can advise on that.

http://www.chainreactioncycles.com/...gclid=COjE1LTN8cUCFQHJtAod0XoAUA&gclsrc=aw.ds


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## Brandane (2 Jun 2015)

ScotiaLass said:


> Okay, I have replaced the chain on the MTB but now it's skipping all over the place!
> I've been told I should have replaced the rear cassette as well. What should I replace it with?
> 
> The bike has a 'Sunrace 9 speed 11-34' on it.
> I want something a bit better. Suggestions please?


Take yer pick! My personal preference is SRAM or Shimano. You might want to match brand with your new chain, but it's not essential. Worn cassettes with new chains doesn't work, as you found out. Neither do new cassettes with worn chains. How are your chain-rings? (They last a lot longer than chains/cassettes).

Edit .... I would go with @sittingbull 's SRAM PG950 at that discounted price.


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## Pale Rider (2 Jun 2015)

I have a Shimano SLX on one of my bikes - the £20 one in Brandane's link.

Hard to see how it's worth spending any more, but if you fancy something dearer either the £30 Shimano XT or the £30 SRAM will almost certainly be quality pieces of kit.


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## ScotiaLass (2 Jun 2015)

sittingbull said:


> Assuming you wish to keep the same range of gear ratios I would go for a SRAM PG-950 11-34T


I was just looking at that one...seems a good price.
Of course to fit myself I'm going to need the tools...does it ever end


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## sittingbull (2 Jun 2015)

Chain whip & lockring tool

The lockring tool shown above with the central locating spindle is preferred by some, including myself.

It never ends, but the tools will pay for themselves


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## Fubar (2 Jun 2015)

ScotiaLass said:


> I was just looking at that one...seems a good price.
> Of course to fit myself I'm going to need the tools...does it ever end



Might need to replace your front chainrings too...


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## ScotiaLass (2 Jun 2015)

Fubar said:


> Might need to replace your front chainrings too...


Gawd.....


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## ScotiaLass (2 Jun 2015)

Fubar said:


> Might need to replace your front chainrings too...


Are they sized like the rear (11-34) or a standard fit?


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## ScotiaLass (2 Jun 2015)

How do I know if either/both need replacing? Would a photo help?


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## sittingbull (2 Jun 2015)

I'd be surprised if your chainrings needed replacement yet (unless it's an old bike with previous wear).

I've got over 15000 miles on mine on a road bike. If you're constantly riding on gritty/gravelly trails then they may show signs of wear.

EDIT: cross-chaining (big/big or small/small wears them prematurely).


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## ScotiaLass (2 Jun 2015)

sittingbull said:


> I'd be surprised if your chainrings needed replacement yet (unless it's an old bike with previous wear).
> 
> I've got over 15000 miles on mine on a road bike. If you're constantly riding on gritty/gravelly trails then they may show signs of wear.


Yeah...gravel towpaths etc


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## ScotiaLass (2 Jun 2015)

Rear






Front


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## Fubar (2 Jun 2015)

sittingbull said:


> I'd be surprised if your chainrings needed replacement yet (unless it's an old bike with previous wear).
> 
> I've got over 15000 miles on mine on a road bike. If you're constantly riding on gritty/gravelly trails then they may show signs of wear.
> 
> EDIT: cross-chaining (big/big or small/small wears them prematurely).



I think it depends on the quality of the components, and if there is new chain/cassette it MAY show on the chainrings.


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## Fubar (2 Jun 2015)

ScotiaLass said:


> View attachment 90587
> 
> Rear
> 
> ...



Teeth do look a bit worn, difficult to tell though - no idea about sizing. Not saying they HAVE to be replaced, just something to look out for.


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## ayceejay (2 Jun 2015)

I would say that two of your front chain rings are worn but your cassette isn't although it is difficult to see the small cogs. As evidence check the different shape of the teeth in the small chain ring (which you probably don't use much with the shape of the teeth on the other rings.


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## sittingbull (2 Jun 2015)

They do look worn, particularly the big ring but having not worn any out myself I wouldn't like to comment on just how worn they are.

I think the angle of the pics could be a little deceptive, square-on is usually best.

If the new chain is slipping on the cassette then the only option is to replace the cassette and see how things are then. I'd suggest using a chain wear indicator to monitor future chain wear. I've got partially worn cassettes on which a new chain has slipped that I've had to remove. However they've worked fine once refitted after the new chain has had a few hundred miles of use.

Once the chain wear indicator (0.75%) fits into the links at 3 points around the chain then I bin the chain. This hopefully preserves the cassette, you shouldn't need a new cassette with each new chain.


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## mr messy (2 Jun 2015)

Is it skipping in all gears?


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## Pale Rider (2 Jun 2015)

Cassette looks fine to me.

Middle ring at the front is showing some typical 'shark tooth' wear.

Does the chain slip when it's on either the smallest or biggest ring?


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## sittingbull (2 Jun 2015)

I've had cassettes that have looked fine over 80-90% in comparison with a new one. The problem has been the one or two cogs that I use most.


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## Hugh Manatee (2 Jun 2015)

I've seen a lot worse; mine for example. I wait until everything is totally worn out and then replace everything. My standard test is to remove the cassette and a chainring. I then take the cassette apart and throw a selected sprocket and the chainring at a brick wall.

If they are sharp enough to stick in the wall then it is time to replace and I donate them to the local ninja training centre.

If they fall to the ground then it is back on the bike for another six months. I last did my touring MTB about 15000 ago. It'll soon be time I suspect!


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## sittingbull (2 Jun 2015)

Hugh Manatee said:


> ........ I wait until everything is totally worn out and then replace everything ........



I'm guessing this would work until the chain eventually slips or snaps.


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## Hugh Manatee (2 Jun 2015)

I have only ever snapped one chain. I was grinding up a very steep hill at Uni in the dead of night somewhat the worse for alcohol. It hurt, but luckily nobody was around to:

1 Laugh.
2 Run over my groaning remains writhing in the road.


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## ScotiaLass (2 Jun 2015)

mr messy said:


> Is it skipping in all gears?


Not all. gears 1-4 are bad....also 16-18 ish....


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## ScotiaLass (2 Jun 2015)

Pale Rider said:


> Cassette looks fine to me.
> 
> Middle ring at the front is showing some typical 'shark tooth' wear.
> 
> Does the chain slip when it's on either the smallest or biggest ring?


Small ring yes, a few gears in the middle ring but none on the big ring


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## mr messy (2 Jun 2015)

ScotiaLass said:


> Small ring yes, a few gears in the middle ring but none on the big ring


Is chain correct length for your setup?


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## ScotiaLass (2 Jun 2015)

mr messy said:


> Is chain correct length for your setup?


Yes


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## ScotiaLass (2 Jun 2015)

Well I say yes. It was as it was when I got it...


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## mr messy (2 Jun 2015)

If cassette worn it would be more big ring slippage. Is it definitely slipping as opposed to skipping between gears at back?
Is there any play in bottom bracket?


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## ayceejay (2 Jun 2015)

For some reason you are not getting my contribution Scotia Lass can you read this?


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## ScotiaLass (3 Jun 2015)

ayceejay said:


> For some reason you are not getting my contribution Scotia Lass can you read this?


Yes I can see your post


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## ScotiaLass (3 Jun 2015)

mr messy said:


> If cassette worn it would be more big ring slippage. Is it definitely slipping as opposed to skipping between gears at back?
> Is there any play in bottom bracket?


It doesn't feel like it's skipping....when you pedal it's 'lumpy' and varies between catching and not catching (so slipping). Does that make ANY sense?


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## ScotiaLass (3 Jun 2015)

I'm thinking this is beyond my capabilities right now and am going to call the LBS (where I bought it). 
I don't want to be without my MTB as I use it most of the time, but it needs sorting properly and I do have the hybrid....I just can't tear about on that they way I do on the MTB


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## Mo1959 (3 Jun 2015)

ScotiaLass said:


> I'm thinking this is beyond my capabilities right now and am going to call the LBS (where I bought it).
> I don't want to be without my MTB as I use it most of the time, but it needs sorting properly and I do have the hybrid....I just can't tear about on that they way I do on the MTB


Please don't be offended, but I don't suppose you could have threaded your new chain through the derailleur incorrectly? Just a thought.


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## mr messy (3 Jun 2015)

Sounds like slack chain since happening on smaller rings. Re check length and as @Mo1959 says routing at rear mech,also if its 'spring' taking up the slack


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## ScotiaLass (3 Jun 2015)

Mo1959 said:


> Please don't be offended, but I don't suppose you could have threaded your new chain through the derailleur incorrectly? Just a thought.


No I did check to make sure it was all the right way around...and got Mr SL to double check it.


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## ScotiaLass (11 Jun 2015)

Picked up the bike today. New rear cassette and running like a dream!


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## Motozulu (28 Jun 2015)

Happy ending!


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