8 speed with 9 derailleur?

Muddy Beast

ok well i got a new bike and its an 8 speed....when i bought the bike i also bought a new LX rear derailleur because it was on sale...what i dint relize was the derailleur was a 9 speed...and my bike is an 8 speed....and of course the guy selling me the bike dint say anything or even realize the bike was an 8 speed....so im stuck here...i figured 1 i could put the derailleur on and adjust it to make it work *if possible?* or try and return it and get an 8 speed online? basically will a 9 speed rear derailleur work just as well on an 8 speed system with out much pain and suffering?

~Scott

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ib69nu

I have a brand new Shimano LX derailluer on my 8speed. it actually depends on your shifters. Most of the time if you have shimano shifters, you will be able to run that derailluer, as long as it is adjusted.

Solanog

I had an 8spd set up in my bike, it had an Acera deraileur I upgraded to a 9spd Deore and it worked as intended, then I upgraded the rest of the drivetrain to 9spd LX (shifters, cranks, cassette, chain) and kept the same Deore rear deraileur, it works great. BTW I've been told that you can even use a 9spd chain on an 8 spd setup, better chains are available for 9 than for 8. I also am running a Shimano 600 rear deraileur on an 8spd setup on my road Bike, if somewhere in time I upgrade to 10 I'll keep this deraileur since it works very nice.

el Inglés

old STX used to be fitted as 7 or 8 and as it´s cable pull that decides how many gears and thats decided by the shifter ..........
eg , old shimano 600 being used on a MTB 9 speed .

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' too old to rock 'n' roll : too young to die '

Muddy Beast

so my LX derailleur that is intended for a 9 speed, and even says mega 9 on it will work just as well as an 8 speed LX? because the LX model i have is a 2005 and it just says for 9 speed but the 2004 LX model says that it works 7-9....i wonder if its the same for the new one but just doesnt say it? because i got a killer deal on the LX rear and and get an 8 speed for the same price just have to wait longer...and its a year older...should i stick with my 9 speed rear derailleur and put it on my 8 speed rear set up...*i have avillo speed-trigger shifters and a spram cog...*

~Scott

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Solanog

My Deore has a sticker (mega 9 or something) and it was working fine on the 8spd setup I had. The only thing that comes to my mind that will make it fail is that the 8spd chain wouldn't fit because it could be to wide but I don't think so, differences in chain width from 8 to 9 are very small.

Muddy Beast

hmm alright thanks ill try putting it on a little later...

~Scott

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moparchris

it will work, its not ideal but will still work, probably better than whatever it was that you have as original still

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GT Ruckus SS
2006 Giant Trance 1
Giant TCR Euro

Solanog

Why will the deraileur won't work ideally?

triguy98

Don't worry about it. A lot of the eight speeds still being sold now have deore 9 speed derailleurs. The shifter dictates the indexing of the RD. If you wanted to upgrade to full 9, youd have to replace the cassette and shifters. Stick with the 8 speed, as it works just fine.

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Muddy Beast

thanks...yeah i just put on the rear derailleur it shifts alot better....just havent tried it out while riding yet...just hand pedaling...but i just discovered my new rear hub is bent..so i need to take of the derailleur and bring it to supergo to get fixxed to reinstall...*incase if they dont allow tampering, they wont know the better*

~Scott

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moparchris

the 9spd derallieurs are meant to be used with the slightly thinner 9spd chains but pft, they work fine

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GT Ruckus SS
2006 Giant Trance 1
Giant TCR Euro

Muddy Beast

ughh...having trouble adjusting it just right....i can get it to shift from 8 to 4 but the other gears *1-3* it just wont shift to...i cant figure out why....

....aslo I know someone who will sell my XT rear, LX front and Deore shifters *fr and rr* for 50 bucks....there for a 9 speed system....will they all work with my 8 or should i switch the cassette too?

~Scott

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el Inglés

have you replaced the cables and outers recently ? most modern shimano shifters are really sensitive to duff cables as they use a weaker spring than the older units .
one symptom is that you can adjust for upshifts or downshifts but not both .

is the chain too long / short ? big ring - small sprocket and the pulleys should be vertically aligned .

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' too old to rock 'n' roll : too young to die '