Can you fit an expander to a 9 speed set up?

Alan P

A pal of mine has a 2010 Scott Genius with a 3 x 9 speed set up (QR9 axle) with an 11/34 cassette and wants to go for a 1x9 or even better, 1x10 set up (preferably a 32 at the front). However, does anybody know if he can fit an expander ring (40T) to a 9 speed cassette, either keeping it 9 speed (so dropping a cog somewhere) or adding to make it 10 speed?

Cheers

The Rookie

If he fits one of the expanders that is just a single sprocket, I see no major issue with it, though he'll have a bigger ratio drop (to 34) than you get with 10 speed (to 36). He may need a really thin spacer to get the gap to the first sprocket of the rest of the cassette right, but probably not, also a 9 speed mech with it's lower largest sprocket capability may suffer......really only one way to find out, but for the cost I'd go 1x10 with conventional parts first.

benpinnick

As above watch out for spacing issues. The cassette might not bind properly as 8x9spd cogs plus the 10 won't be as wide as 9x9

jimothy78

benpinnick wrote:

As above watch out for spacing issues. The cassette might not bind properly as 8x9spd cogs plus the 10 won't be as wide as 9x9

This is true, but if my maths is good, the difference between the two is only 1.11% of the total (normal) width, which equates to about 0.4mm. Unless the existing setup is running at a tiny amount of tolerance, it should be ok.

FishFish

Check the cage size too for confirmation ist can cope with the expanded caseette.

allthegearnoidea

in the last edition of Cycle mag from ctc there was a guy who exp[lained what he did to go 1x9 with a range expander cog fitted, can't remember of the top of my head which of the smaller cogs he lost(7th or 8th gear) to allow for the larger cog, sure there was a spacer mentioned too and a Longer b screw, but sadly the mag went out in the recycling last week,
i've been contemplating it somewhat,

Alan P

Ok, thanks guys. So it's a case of go for a 10spd cassette 11/36 and maybe try that first, then if that's ok then as long as the mech can be adjusted (presumably the B screw), then a 40t expander should be good too (presumably removing the 17t cog)

jimothy78

Alan P wrote:

Ok, thanks guys. So it's a case of go for a 10spd cassette 11/36 and maybe try that first,

But bear in mind that if you change the cassette to 10 speed you have to change the derailleur and shifter as well, anyway.

Alan P

Good point....I forgot about the shifter! Thanks

The Rookie

And chain of course......

Alan P

This is getting more expensive for him by the minute!

njee20

It's been said - but you know he needs a rear mech as well, worth repeating!

FishFish

..and a steeper hill of course. And a new car to get him there.

Alan P

And the list goes on....

mattrixdesign2

and a small bank loan

The Rookie

To summarise...
9-10 speed means cassette, chain, shifter and mech UNLESS you use Shimano flat bar road shifters when you can use a 9 speed mech.

rockmonkeysc

Man up and do without the range expander. With a 32t up front it shouldn't be too tough.