Bicycle Mechanics - Sram 8speed shifter compatibility

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doco
05-13-08, 04:24 PM
I want to double check with you guys before I guy this

I have a Sram 8 speed shifter that works with ESP 1:1

I have a rear hub, with 8 speed cassette

I can get a good deal on a Sram 9 speed rear deralleur that will work with ESP 1:1

can I do this this? I think it will work

and if I have this right, it will work because the rear mech limiting screws up/down can be adjusted to the 8 speed cassette

and a 9 speed derailleur will work with a 7.8.9 shifters

am I right on this??

Bill Kapaun
05-13-08, 04:34 PM
The cog spacing is different between 8 & 9 speed cassettes. 9 speed has narrower spacing so that you can fit the extra cog on the SAME Free Hub.
doco
05-13-08, 04:42 PM
yes, the hub can take either a 8 or 9 speed casstte,

what i need to know will the rear 9 speed derailleur work with a 8 speed shifter?

Bill Kapaun
05-13-08, 05:04 PM
Your 9 speed shifters will NOT shift the 8 speed cassette properly!
A 9 speed shifter has a different amount of cable travel than an 8 speed shifter, per shift.
7 shifts for X distance on an 8
8 shifts for the SAME distance on a 9.

The DER doesn't care. It only moves the amount determined by the shifter.
Retro Grouch
05-13-08, 05:07 PM
yes, the hub can take either a 8 or 9 speed casstte,

what i need to know will the rear 9 speed derailleur work with a 8 speed shifter?

Without a doubt it will work.

Think of it this way. A rear derailleur guides the chain by the middle of the chain. It doesn't care if the outside of the chain is a little wider or a little narrower.
doco
05-13-08, 05:15 PM
Without a doubt it will work.

Think of it this way. A rear derailleur guides the chain by the middle of the chain. It doesn't care if the outside of the chain is a little wider or a little narrower.

Thanks, that is what I thought .. you can have a front 7-8-9 and a rear 9 and any combo will work

you can also have a for example 8speed front shifter and a 7 speed rear derailleur

that is what the limiting screws are for...


thanks again, slowly getting it
doco
05-13-08, 05:23 PM
Your 9 speed shifters will NOT shift the 8 speed cassette properly!
A 9 speed shifter has a different amount of cable travel than an 8 speed shifter, per shift.
7 shifts for X distance on an 8
8 shifts for the SAME distance on a 9.

The DER doesn't care. It only moves the amount determined by the shifter.


Bill, I am confused, I have 8 speed shifters (not 9 speed)

so as above post, my 8 speed shifter will work with the 9 speed REAR
Bill Kapaun
05-13-08, 08:31 PM
OK, I missed what you were saying.
The DER should work fine.
The shifters have to match the cassette.
7-7, 8-8, 9-9
doco
05-13-08, 10:04 PM
ahhh that's better :) not confused anymore..thank you Bill


I have an 8speed 11-32 cassette on a shimano hub, 8speed shifter on handlebar and the 9speed rear derailleur I am going to buy
DieselDan
05-14-08, 06:09 AM
Your shifter and cassette must match.
Matt Gaunt
05-14-08, 06:34 AM
OP: essentially, ignore all the posts apart from Retro Grouch's for the most simple answer (which is correct as usual).