Shimano Alivio/Deore front derailleur

[konguito]

Hi all,

I have a bicycle with a Shimano Stx rc crankset, 8 speeds and a Shimano Alivio front derailleur. I must change the Shimano Alivio and I would like to replace it by a Shimano Deore. However, the Shimano Deore is for 9 speeds (9x3) and I have been told that I shouldn´t install it as my bicycle has only 8 speeds (8x3). Is that true?.

Thanks a lot for your help

 

[bike_builder]

Originally posted by konguito
Hi all,

I have a bicycle with a Shimano Stx rc crankset, 8 speeds and a Shimano Alivio front derailleur. I must change the Shimano Alivio and I would like to replace it by a Shimano Deore. However, the Shimano Deore is for 9 speeds (9x3) and I have been told that I shouldn´t install it as my bicycle has only 8 speeds (8x3). Is that true?.

Thanks a lot for your help

Ok,

The compatibility issue is not with the 8 speeds in the back but the 3 up front. Shimano 8-speed system is designed around a 42/42/22 front chain wheel. So what that means is the front derailleur you have is set up to work best shifting a 42t to 32t jump on the chain wheel. The Deore is set up for the 9-speed system that uses a 44/32/22 front chain wheel. The Deore front derailleur is set up to shift a 44t to 32t jump on the chain wheel. You’re better off getting an Alivio replacement; the Deore would do teh job but it's not going to get you any thing in the way of better performance.