Changing from 8 to 9 speed

[Jimmy Doug]

Hi

Well, it's looking like I need to change my rear derailleur. Currently, I have an 8 speed with Shimano sti shifters - but looking in Wiggle's extensive catalogue, I see that there are very few 8 speed derailleurs these days; most seem to be 9 or 10-speed. So, as I've already had to spend a fortune on parts recently, is it possible to buy a 9-speed derailleur and fit it on my current configuration (ie, 8-speed cassette with 8-speed sti shifter)? I suppose it should be possible, but what about the difference in chain thickness? Also, just how reliable are 9-speeds? I read somewhere that a 9-speed chain isn't as strong as an 8-speed one; this for me is an important consideration, because I do a lot of touring in the summer, and I don't want to end up with a broken chain in the middle of nowhere.

Cheers for your help

 

[MattHB]

I have a 10 speed chain and dream of producing enough power to break it. It ain't going to happen unless you do zero maintenance and wear it out way past its tolerances in which case it's your own fault

 

[Moodyman]

Dérailleur speeds are misleading. Speeds are dictated by the shifter pull, the derailleur just does what the shifter tells it. So, a 9 speed derailleur will work with your current 8 speed set up. If you want to change everything over to 9 speed then gonna be expensive as need to change shifters, cassette and chain.

 

[Jimmy Doug]

Thanks. So what about the chain thickness? Will it fit properly on an 8-speed cassette and chainring?

 

[Peteaud]

Hi

Well, it's looking like I need to change my rear derailleur. Currently, I have an 8 speed with Shimano sti shifters - but looking in Wiggle's extensive catalogue, I see that there are very few 8 speed derailleurs these days; most seem to be 9 or 10-speed. So, as I've already had to spend a fortune on parts recently, is it possible to buy a 9-speed derailleur and fit it on my current configuration (ie, 8-speed cassette with 8-speed sti shifter)? I suppose it should be possible, but what about the difference in chain thickness? Also, just how reliable are 9-speeds? I read somewhere that a 9-speed chain isn't as strong as an 8-speed one; this for me is an important consideration, because I do a lot of touring in the summer, and I don't want to end up with a broken chain in the middle of nowhere.

Cheers for your help

Any deraileir will fit exept the newer 10 speed ones.

so for you a mountain bike rear mech, i.e deore will fit.

 

[Peteaud]

here you go :-
http://www.wiggle.co.uk/shimano-m36..._campaign=uk&gclid=CLnzrci6-7MCFcrItAod-kEAUg

 

[Moodyman]

Thanks. So what about the chain thickness? Will it fit properly on an 8-speed cassette and chainring?

Yes.

 

[Peteaud]

Ignore the chain, 8 speed cassette and 8 speed chain you already have.

You need a rear mech and if it was me i would get a new cable inner at the same time as its less hassle.

 

[Jimmy Doug]

here you go :-
http://www.wiggle.co.uk/shimano-m36..._campaign=uk&gclid=CLnzrci6-7MCFcrItAod-kEAUg

This is the one I already have. Reckon if I'm going to change, I might as well upgrade to something a little better: an XT or Deore, for example.
So, if I understand you all correctly, I just buy a 9-speed derailleur and use it with my current 8-speed chain - then, when the time comes, change chain, cassette, shifters and chain-ring at the same time? As it happens, the shifters and chain-rings do need to be changed, but it's not urgent.

 

[Peteaud]

This is the one I already have. Reckon if I'm going to change, I might as well upgrade to something a little better: an XT or Deore, for example.
So, if I understand you all correctly, I just buy a 9-speed derailleur and use it with my current 8-speed chain - then, when the time comes, change chain, cassette, shifters and chain-ring at the same time? As it happens, the shifters and chain-rings do need to be changed, but it's not urgent.

Yes.

But, the main difference between Deore, XT, XTR is marketing imho.

Deore is good enough for most but there is nothing wrong with Acera. Its a few grams heavier and not as flash but does the same thing, so i would go for that, save your money and then upgrade later.

If you do go for Deore, then Merlin have them for a good price.

http://www.merlincycles.com/bike-sh...mtb/shimano-deore-m591-9-speed-rear-mech.html

Even says 8 & 9 speed on the spec.

 

[Peteaud]

For what its worth

The shifters and cassette must be the same, i.e 8 speed, 9 speed etc.

The chain is to suit above

The rear mech only does what the shifter says in terms of pull of cable to movement.

 

[Jimmy Doug]

Thanks for all the advice, guys. This is all much clearer to me now. Thanks for the linky Pete - it's a good saving. Might even order today.

Cheers once again!

 

[P.H]

What others have said, I change back and forth between 8 & 9 on friction shifters without any problem.
Another option for a good quality mech, I can recommend the seller;
http://www.ebay.co.uk/itm/Shimano-L...sure_cycling_bikeparts_SR&hash=item484732984b

 

[Jimmy Doug]

That's interesting. Is there a difference between these two Deores, apart from the price and the colour? The one in Pete's link looks longer, or maybe that's just the photo?

 

[P.H]

That's interesting. Is there a difference between these two Deores, apart from the price and the colour? The one in Pete's link looks longer, or maybe that's just the photo?

In practice, there's probably no difference. Deore LX is Shimano's touring/trekking groupset and Deore is aimed at MTB. The list price for LX is slightly more than for Deore. They are both designed to use the same cassettes, both should give years of trouble free use, if it were me I'd choose the colour that best suited the bike, or the cheapest.