Which rear mech?

blue.mouse

Newby to doing up a MTB with shimano bits and bobs and is a 24speed but the rear derailleur has just broken - it was a deore lx.

Went to order one as I fancy having a go at replacing it myself (why not it isn't an expensive bike?) but am lost as to which to buy. There seem to be about loads of different shimano deore rear derailleurs!!

As the numbers increase does that mean it is better? If so, how? Will I really notice the difference?

Anyway which would you suggest?

M592
M662 or just get a cheap tourney?

http://www.ukbikestore.co.uk/product/21 ... ormal.html

http://www.totalcycling.com/index.php/p ... ncy&id=GBP

Thanks,

Rich

blue.mouse

This is exactly why I am asking you for advice - what WOULD you suggest? I thought a 9 speed derailleur would still work on an 8 speed and am just a beginner who knows almost nothing about changing it but willing to have a go. I need to start from somewhere and will ask stupid questions but wanted to improve my own knowledge rather than take it down to Halfords/local bike store.

So thanks for the patronising tone but what would you suggest? I'm looking for help and can't seem to get any from books etc; I was hoping to get it from here, but clearly not.

Chris McG

Bigger numbers mean a better quality component...

I think that the Deore one (m591) is probably good enough... there isnt much difference between it and Deore LX

(as a rule I think that Deore is the minimum you should get)

EDIT: A 9 speed rear mech should work fine with the 8 speed system...

paulbox

blue.mouse wrote:

So thanks for the patronising tone but what would you suggest? I'm looking for help and can't seem to get any from books etc; I was hoping to get it from here, but clearly not.

Calm down mate, I re-read my post and deleted it before you posted this as I thought it made me sound like a bit of a tw@t...

I'm sure somebody will help you.

supersonic

Any 7/8/9 speed Shimano derailler will work: I'd get this -

http://www.woollyhatshop.com/Shop-By-Br ... _2585.html

rhext

I think the range goes Tourney, LX, SLX, XT, XTR. The SLX is the M662.

I replaced my LX with an SLX recently and, somewhat to my surprise, found it noticeably better. Not quite sure why, as the shifter is still the same: must have better springs or something because the shifts definitely felt slicker.

If I needed a new one I'd buy another SLX: I guess XT and XTR might be better still but the SLX is so good, I'd struggle to see how the other two could make enough of an improvement to justify the cost increase. But I'd not be tempted to save a few quid and get one of the cheaper ones because I like the feel of the SLX.

Having said that, if I were just putting together a 'cheap as possible' hack bike, the LX was decent quality and worked reliably. And I suspect the Tourney would too.

I'm pretty sure that a 9-speed SLX will work with an 8-speed shifter, but you probably ought to ring the shop to confirm first.

Stan..

supersonic wrote:

Any 7/8/9 speed Shimano derailler will work: I'd get this -

http://www.woollyhatshop.com/Shop-By-Br ... _2585.html

I put one of these on my old 7 speed for the first time a week or so ago and it seems to work fine to me. I just took the old one to the LBS and asked them to recommend something as I did not know what would work. After watching a few YouTube videos it was easy to replace and then reset the gears. I also add a new gear cable as that was trashed at the same time.

blue.mouse

Thanks for the advice - will probably go with gut instinct and buy the m591 which seems like good mid range kit.

Couple of stupid questions though:

will I need to buy a chain tool? If so any advice? Are there any tools I will need?
will I need a shimano chain? I have no idea what this one is - it says France and PG on it but can't references on net
will I need a new cable?

As you can tell I'm starting out and haven't got a lot of a. experience; b. knowledge and c. tools!

cooldad

No, you can just remove the lower jockey wheel, although a chain tool is useful.
No any 8 speed chain will be fine. Get one with a master/poerlink iff possible. But then you will need a chain tool to get the right length.
I would anyway, but only needed if the old one is finished (or has frayed ends).

rhext

Chain tool - depends on what you have fitted currently. If it's a shimano chain you will need both a tool (to break your current chain), and a new 8-speed link pin to reconnect it. Google search on the internet will help you with this.

If it's a SRAM chain, it will have a power-link, which you can use to break it without a tool and rejoin it. If it's neither, look carefully at it: if you can't find a link which is different from the rest it's a chain tool and new link pin I'm afraid.

It might be worth buying a new chain anyway: I'd recommend an SRAM 9-speed chain, which will come with a power link, making it much easier to refit. The 9-speed will be fine on your 8-speed cassette (I have a similar set up on my road bike). Unfortunately you'll still need a chain tool to break the old chain and trim the new one to size.

Get a good quality chain tool (eg Park Tools). Cheaper ones can be had, but if the pin is even slighly bent they're an absolute pig to use....

You probably won't need a new cable, but I'd strongly consider fitting one while you're at it. New cables are cheap and make a real difference to shift performance if your old one's in poor condition.

chicken_leg

Pedros do a really nice chain tool. Comes with a little clip to hold the chain together when you rejoin it, and the pin is screwed in so it won't drop out and roll down the back of your workbench like my old one did! :roll: