Which Cassette will work?

If it has a SRAM cassette, you will be able to install a shimano cassette definitely, campy takes different splines.
There is one spacer required for 10 speed cassettes on a 9-speed body, just ask your LBS, it is a small metal ring.

sp103154 said:

I have an ALex (A-Class) AKX-R1 rear Hub (I guess also called free hub) with an SRAM 9 speed cassette.

Question: Can I install a 10 speed cassette and which one: SRAM, CHIMANO, IRD and, besides the new 10speed CHAIN, will I need any (SPACERS) as well?

All of the mentioned 10s cassettes should work--and for shimano you will need the spacer between the freehub body and the largest cog--I am not sure about a spacer the SRAM or IRD 10s (never used them yet).

John M said:

All of the mentioned 10s cassettes should work--and for shimano you will need the spacer between the freehub body and the largest cog--I am not sure about a spacer the SRAM or IRD 10s (never used them yet).

I have a ? about this spacer. The 9sp cassette has a total thickness of 36.5mm. The computed thickness of the 10sp is 37.15mm (.65mm diff.) Why then is a spacer required to use a 10sp cassette on a 9sp hub?

OK,I found the answer. Although it only applies to DA and Ultegra 10 cassettes.

In most cases you can use a 10 speed cassette on a 9 speed hub except in the following combinations:

- CS-7800/6600 gear combinations 11/21, 11/23, 12/21, 12/23 cannot be used on WH-6500 and WH- 7700 wheels.

- CS-7800 gear combination 11/21 cannot be used on WH-R540 wheels.

- WH-R535 wheels cannot accept any CS-7800/6600

NOTE: When installing the CS-7800/6600 on a 9 speed freehub, you must use the supplied 1mm spacer (part# Y1Z807000) behind the cassette. To space the gear properly in the frame.

Xsmoker said:

I have a ? about this spacer. The 9sp cassette has a total thickness of 36.5mm. The computed thickness of the 10sp is 37.15mm (.65mm diff.) Why then is a spacer required to use a 10sp cassette on a 9sp hub?

NOTE: When installing the CS-7800/6600 on a 9 speed freehub, you must use the supplied 1mm spacer (part# Y1Z807000) behind the cassette. To space the gear properly in the frame.

Yeah, I don't know why they have to use a spacer, must be chainline:indexing or something similar. BTW, is that a self contradiction, or a misunderstanding on my behalf (the 'I have the answer' was there so I will assume a misunderstanding)

bobbyOCR said:

BTW, is that a self contradiction, or a misunderstanding on my behalf (the 'I have the answer' was there so I will assume a misunderstanding)

Right after I posted the question I went looking for the answer. After all, I have the world at my fingertips.