2300 cassette + rear derailleur replacement

[steve451]

Hello, wondered if I could get some advice
I wanted to turn my specialized tricross into a weekend (rear panniers only) touring bike.
I wanted to lower the gearing - currently it has an sram 11-28 8 speed cassette and a Shimano 2300 RD.
I have an hg 11-32 8 speed cassette I would like to use , does anyone know a suitable
rear derailleur , I can use - cheapest possible ? The 2300 RD seems a bit short to accomodate the 32T

I read the Sheldon Brown gearing pages but still cannot work out what RD i need ( thicko! )

cheers steve


tricross
Chainset:Shimano 2300
Chainrings:52/42/30 tooth chainrings
Shifters:Shimano 2300 Sti
Chain KMC Z-51
Rear Derailleur Shimano 2300

 

[steve451]

Maybe I am just asking what STI compatible derailleur can I run a 32T cassette with ?

 

[RecordAceFromNew]

According to RD2300's spec it would be breaching both max cog size (32 against 26) and wrap capacity (52-30+32-11=43 against 35). Nevertheless since you have already got it and since there is a chance it might still work so you might want to try, this is an excellent guide.

If not or if you can't be bothered you should get a Shimano mtb rear mech, The only other rules you must stick to is it should be an SGS version (i.e. not the GS variant) and it must not be for 10 speed. There are lots of choices.

Assuming the current chain length is perfect you will also need a longer chain with a pair of extra links.

 

[TheDoctor]

Another option is to fit a smaller inner ring.
You can get down to a 24T inner ring, and that'll give you a gear for going up cliffs.

 

[steve451]

Many thanks for the replies,

I had thought that the mtb RD could not be used with STI shifters, think i will go with the Deore 9 speed.
I had no idea that I could use the mtb style RD with the STI shifters. I find the Shimano compatibility thing quite confusing.
Do not think I will go for 24T inner ring as size difference might be tricky (52 out - 24 in) ? and may end up needing new FD. (Although this could be a good idea for my hybrid)
Also if Deore RD does not work can always stick it on my old hybrid.

Did have a look at it and there just wasn't the clearance between RD and cassette unless pulled
unfeasible far back.

 

[TheDoctor]

If it helps, I've just-this-second finished fitting a 11-32T cassette to my road bike. There's some interference between the jockey wheel and the 32T sprocket, but it's usable. I'd try your original rear mech and see how you get on.
As far as Shimano indexing goes, Shimano rear mechs all have the same cable pull, so 8/9 speed Deore will work fine with STIs.
It's front mechs that are different. And DynaSys (10 speed MTB) rear mechs are different as well.

 

[Nebulous]

I have one of these. It comes with Shimano 2300 shifters and an Acera rear mech. It changes pretty well.

 

[Peteaud]

11-34 cassette, Deore mech and new chain is the best answer.

Available from merlin cycles.

 

[steve451]

Well finally got round to it , went for Alivio M410 7/8 speed (£19 from CRC - Deore was £30) Quality wise I think it lies between Acera and Deore.
It tuned in easy, have only ridden round the block but seems absolutely fine with the 11-32 cassette and new chain, Tempted to get that 34 cassette later in the month, once again thanks .