Can I use a Shimano Alivio 7 speed shifter with Shimano Deore 9 speed drivetrain? Basically the bike originally came with everything being set up for 7 speed. Somebody switched out my tire/rim and left a 9 speed tire/rim as a replacement. I'm hoping to find the cheapest way to correct this? Also my chain was originally for a 7 speed, does it matter now that there is a 9 speed drivetrain? Do I need to replace it? Thank you to anyone that can offer some info on this and point me in the right direction.

  • 1
    someone stole your 7 speed wheel and left behind a 9 speed wheel? I'd check that over VERY carefully before using it. Also ask-around and see if someone else had the opposite happen. A swap-back would be no-cost.
    – Criggie
    Commented Oct 6, 2022 at 18:38

1 Answer 1


The cheapest way would probably be to remove the 9 speed cassette from the wheel and replace it with a 7 speed cassette (of the same ratios you previously had) and the appropriate spacer (4.5mm thick, the spacer goes on the freehub first, followed by the 7 speed cassette). This is likely the cheapest approach.

A Bike Exchange question from years back can offer insight:

7-speed MTB cassette on 8/9-speed wheel hub, where does spacer go?

Reason: to convert to 9 speed, you would need a different front shifter if it is index shifting. You would also need a new chain because a 9-speed chain is narrower than a 7-speed chain. You may even need to change out your rear derailleur if it does not have the range to handle the 9-speed cassette you have.

You also did not mention the state of the 9-speed cassette you have. If it is worn, then you would be replacing that as well to go 9-speed.

Note that your rear wheel can natively accommodate 8, 9, and 10 speed cassettes, and some 11 speed cassettes if they are large enough (a 34 tooth [or larger] largest cog in the Shimano realm) without the need for spacers (the exception being 10-speed road cassettes, which use a 1.0mm spacer to fit an 8/9/10 freehub but would still fit).

  • Additionally, if the 7- speed front shifter is indexed it is unlikely to shift a narrower 9 speed chain consistently. The upshift/downshift side plates are too far apart to work in both directions. I have squeezed the plates together with pliers as a hack, and the results were still marginal.
    – mikes
    Commented Oct 6, 2022 at 20:12

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.