# 9 speed shifter compatible with 8 speed drivetrain?



## Hallinator (Jun 26, 2010)

Specifically, would the new Shimano SL-M430 Alivio shifters work with my Specialized Hardrock and its 8 speed Acera RD?


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## safariofthemind (Oct 27, 2010)

Hopefully a mechanic will stop by. In the meantime, here's a link to Shimano's tech document site for you to peruse. Good luck.

http://techdocs.shimano.com


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## jeffj (Jan 13, 2004)

The spacing on an 8 speed cassette is wider between cogs than it is on a 9 speed cassette. The cassettes are the same width overall, but each gap on the 9 speed is slightly narrower, so the indexing doesn't line up.

The 8 speed rear derailleur will work on a 9 speed drivetrain just fine.

If you just get a 9 speed cassette (and chain) to go with the 9 speed shifters, you'll be fine. The cassette will fit on your wheel just fine.


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## big_papa_nuts (Mar 29, 2010)

No.


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## AndrwSwitch (Nov 8, 2007)

jeffj said:



> The 8 speed rear derailleur will work on a 9 speed drivetrain just fine.
> 
> If you just get a 9 speed cassette (and chain) to go with the 9 speed shifters, you'll be fine. The cassette will fit on your wheel just fine.


Since there seems to be some disagreement on this, I'll add my experience.

I had this setup and it worked fine for about a season. Then I fell over to the right and damaged the derailleur.


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## jeffj (Jan 13, 2004)

AndrwSwitch said:


> Since there seems to be some disagreement on this, I'll add my experience.
> 
> I had this setup and it worked fine for about a season. Then I fell over to the right and damaged the derailleur.


:thumbsup: I do not recommend falling over to the right and damaging the derailleur. . . .


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## bad mechanic (Jun 21, 2006)

AndrwSwitch said:


> Since there seems to be some disagreement on this, I'll add my experience.
> 
> I had this setup and it worked fine for about a season. Then I fell over to the right and damaged the derailleur.


Then you either didn't have the shifter or cassette you think you had. 8spd cassettes and 9spd shifter simply don't work; as jeffj said the indexing is off.

A 9 speed chain is also recommended, since the more closely spaced cogs need a narrower chain.


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## AndrwSwitch (Nov 8, 2007)

I meant I had the setup jeffj described - as in 9-speed shifter, 9-speed chain, 9-speed cassette, 8-speed rear derailleur.


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## bad mechanic (Jun 21, 2006)

AndrwSwitch said:


> I meant I had the setup jeffj described - as in 9-speed shifter, 9-speed chain, 9-speed cassette, 8-speed rear derailleur.


Gotcha, sorry. Yes, what you described works nicely.


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## Hallinator (Jun 26, 2010)

Thanks for all your help, looks like i'm sticking with my 8-speed shifters!


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## mitzikatzi (Sep 9, 2008)

If you exclude the new 10spd components.
Derailleurs are the same for 8 speed and 9 speed it is the shifter that is different they "pull" different amounts. If your current wheel has a 8 speed cassette a 9 speed cassette will fit. You will need a 9 speed chain. Change the shifter to a 9 speed one (with a 9 speed cassette fitted) and your old "8" speed derailleur will work fine. As others have said a 9 speed shifter won't work on an 8 speed cassette. 
Remember Sram and Shimano shifters and derailleurs don't mix but you can can Sram attack shifters that will work with Shimano derailleurs.


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## jrabikerepair (Dec 29, 2009)

Be careful when using an 8 speed derailleur on a 9 speed drivetrain. Make sure that your largest rear cog doesn't have more teeth than the maximum on the derailleur, or at the least a long enough cage. It is possible to use it for casual riding.

Also, when it comes to SRAM shifters, anything with a word-ish model name (i.e. MRX, Attack, etc) are compatible for Shimano derailleurs, whereas numbers and high-end letters (3.0, 5.0, X7, X9, X.O, XX) are all Sram derrs only.

Hope this clears things up.


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## rlouder (Jun 26, 2007)

jrabikerepair said:


> Be careful when using an 8 speed derailleur on a 9 speed drivetrain....


Good advice. Just because it will work, doesn't mean it's gonna be great.

You don't mention why you want to change to 9sp. The main advantage of 9sp is the availability of better components. Otherwise, there is very little difference.

Going from your stock shifters to alivio isn't much of a step up. If you change to 9sp you may want to save a bit more. For very little additional cost, some deore or lx shifters and rear der. would be a noticeable improvement (or sram x5/x7).


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## Hallinator (Jun 26, 2010)

> You don't mention why you want to change to 9sp. The main advantage of 9sp is the availability of better components.


Exactly, honestly I'm just putting some Speed Dial 7 levers on and I've got to get new shifters if I replace the integrated levers. I thought I might as well upgrade while I'm at it.


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## AndrwSwitch (Nov 8, 2007)

If you can find some NOS Deore LX or better shifters, that would be a pretty good score.

Otherwise, if you can swing it right now, why not just upgrade to 9-speed? The shifters themselves are really the most expensive part of that change, and the chain and cassette are wear parts anyway.


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## Mr.AllMountain (Dec 4, 2010)

big_papa_nuts said:


> No.


cant get more stright forward than that lol


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