Will a 9 speed fron...
 

[Closed] Will a 9 speed front mech work with 8 speed drive chain?

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Am having trouble sorting out a mates bike.

Not sure if it's possible to avoid the chain catching the mech as it's a tad wider?

The chain will clear granny and 1st and big ring and 8th but when I try middle and 1st or 8th it'll only clear on 8th gear. If I reduce cable tension to clear 1st gear it throws out clearance in big ring and 8th.

I tried setting the mech with 3mm clearance from top of big chainring to start with and have had to move it higher up the seat tube a few times at the moment the clearance is around 8mm.

Think I remember reading that you need to set the mech higher but not too sure.

TIA

Andy


 
Posted : 06/12/2011 7:46 pm
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Anyone>


 
Posted : 06/12/2011 11:24 pm
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I have this setup on 3 bikes, all work fine. Well, I never use the extremes on the middle ring - I didn't think they were valid combinations for the reasons you specify.


 
Posted : 06/12/2011 11:27 pm
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Oh right it can be done then!
I thought in middle ring you should be able use all the gears?
Did you have to set the mech high as well?

Cheers


 
Posted : 07/12/2011 4:43 pm
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It can be done, but you will either catch the chain on the largest or smallest sprocket.
9-speed mech has a narrower cage than an 8-speed.
11/128" versus 12/128" chains.

Want the solution?

Use a 9-speed chain.

KMC guarantee it will work, and I have this working on a couple of 8-speed set-ups to verify the claim.

PaulD


 
Posted : 07/12/2011 5:11 pm
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Cheers Paul I'll suggest that to him, which KMC chain and where's the cheapest place for them?


 
Posted : 07/12/2011 7:54 pm
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i'm using 10 speed road mechs on a 8spd road drivetrain all works fine,
i'm really good at keeping a good chainline though which probably helps

9 speed will be fine


 
Posted : 07/12/2011 8:49 pm
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Cheers for that colande.

Would a sram 9 speed chain work as well as a KMC, think I've got a spare one he could try.


 
Posted : 07/12/2011 10:56 pm
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Mine works fine but you need a 9 speed shifter as with the 8 speed it used to rub.


 
Posted : 07/12/2011 11:50 pm
 GW
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you're only talking 0.15mm width difference at either extreme between 8 and 9 speed chains.
been using 8 speed chains with 9 speed front mechs for years and years with zero rub at the mech cage.

zippykona - cranks' chainring tab spacing hasn't changed (ie. any decent front shifter will be fine).


 
Posted : 07/12/2011 11:58 pm
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Since KMC guarantee their 9-speed chains to work with an 8-speed drive train, I have used other makes (YBN hollowpin from XC Racer and a SRAM PC991) successfully on 8-speed XTR cassettes with M960 rear mechs and a mix of 8 and 9-speed front mechs and 9-speed Shimano shifters.

All OK.

PaulD


 
Posted : 08/12/2011 12:24 pm
 GW
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8 speed chains are almost half the price of 9


 
Posted : 08/12/2011 2:10 pm
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Thanks again.

I cant get it to run clear of 1st and 8th in middle ring with the 8speed chain so I'll try it with the 9 speed chain, the only doubt is how worn his drive chain is and if a new chain (8 or 9 speeed) will run ok.
If that doesn't work then he can take it to the LBS or we'll try an 8 speed front mech!!

Thanks for help


 
Posted : 08/12/2011 3:36 pm