How to tell what 's...
 

[Closed] How to tell what 'speed' rear mech is?

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Afternoon all.

I'm in the process of replacing chain/cassette on my bike. It's a bit of a 'Trigger's Broom' as over the years it's had all kinds of bits put on and taken away, basically a mountain bike on slicks used for bombing around the city/light touring. The chain/cassette I'm replacing are eight speed. It occurred to me that I may as well upgrade to ten speed.

Apparently, the chainrings don't matter so much, but I realise I'll need a new shifter as the present one (Deore) is eight clicks. But I'm hoping to get away with using my current mech's. Dunno what the front one is, but the rear mech is a Shimano Deore XT. Are rear mechs speed specific? it's been ran for ages as an eight speed, but that's no reason to believe the mech is 'eight speed' because the parts have been added randomly over the years: mate gives me his old wheel, chuck it on complete with whatever cassette it had with it etc... you get the vibe.

So, I'm hoping to get a Deore ten speed chain, and this beast of a cassette (Shimano Deore ten speed, 11-42)

Will it work?


 
Posted : 04/03/2018 5:52 pm
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What model is it? There should be a number on it, starting M7...

Also, what length this cage? Long medium or short?


 
Posted : 04/03/2018 6:26 pm
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Shimano changed the cable pull ratio for 10 speed.

You'll need a new rear mech to go with the new shifter.


 
Posted : 04/03/2018 6:37 pm
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All shimano mechs have same cable pull ratio up to 9 speed. After that it changed. So if you have a 10 speed cassette then you'll need a 10 speed dynashift mech and shifter. Unless you use 10 speed road shifters in which case you wil need either a 9 speed mtb mech or a 10 speed or less road mech.

Hope that's clear!


 
Posted : 04/03/2018 6:43 pm
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Hmm, ok. That's a shame. Couldn't see a model number on it. Will have another look tomorrow, though I'd guess it's long cage. So, I'm stuck with eight or nine speed without a new rear mech. Got it. Thanks chaps/chapesses.


 
Posted : 04/03/2018 6:59 pm
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9 speed Shimano should be branded ‘Mega 9’ and 10speed should be branded ‘Dynasys’.

As above, pull ratios changed at 10speed, you’ll be looking to change the RD as well as the shifter.  Unless you have a stash of 10speed cassettes or are using second hand items then it does beg the question why not make it one louder?


 
Posted : 04/03/2018 7:09 pm
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Yes, looks like it'll be easier to go nine speed. Thanks.


 
Posted : 04/03/2018 9:13 pm
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you can get 10sp flat bar road shifters that'd work with that mech, I think (they ceratinly work with an old XTR one that I'm using).  SOmetimes you can get the shifters nice & cheap too

(would prob need a roadlink or similar to get the mech to work with a big cassette though)


 
Posted : 04/03/2018 9:34 pm