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PostPosted: Thu Mar 26, 2009 5:41 pm 
Retro Guru

Joined: Tue Mar 24, 2009 6:10 pm
Posts: 939
Location: Kent,25 miles from France
OK. So I'm still living in the last century and run shimano XT 8 speed on the '97 Karakoram..............

But what if I wanted to run 9 speed or say use a 9 speed rear or front mechs. Will it work ?

I realise that 9 speed chain is only for 9 speed and vise versa. But would a new 9 speed crankset be OK with the IG70 chain and existing 8 speed cassette/rear /front mech ?

I remeber this being a big (ish) debate at the turn of the century, but in the last 9 years my memory ain't what it was.

As for why I 'd want to do it, is that the 8 speed stuff is wearing out and the 9 speed mechs and cranks are easier to get..........But flame me anyway :wink:


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PostPosted: Thu Mar 26, 2009 6:22 pm 
Old School Grand Master

Joined: Tue Oct 09, 2007 1:55 pm
Posts: 8219
Location: New Forest, UK
Shimano did a good job on compatibility and it's all interchangeable. I'm using a 2008 rear mech in a 7s system.

Occasionally you can get problems with some 9s cranksets having the chainrings a little closer together and this can cause rub. A thin washer behind the chainring cures it though.

Hey, this is retrobike. Most of us wouldn't dirty our hands with anything newfangled like 9speed anyway! It also wears out faster...

Anyway, how are your cranks wearing out? Just fit new rings.


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PostPosted: Thu Mar 26, 2009 7:31 pm 
Retro Guru

Joined: Tue Mar 24, 2009 6:10 pm
Posts: 939
Location: Kent,25 miles from France
Not sure I will be fitting anything as fancy as 9 speed just yet.Just wondered on the compatability.

Did consider changing the rings but getting shimano XT 8sd stuff seems to be getting harder,I have found a few local bike shops with it in, but they are asking 2009 prices for stuff they had for 10 years.

I guess that's why I wondered anout the 9 speed stuff fitting (just in case)

At least shimano still make the IG70 chain..........


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PostPosted: Fri Mar 27, 2009 10:22 am 
Old School Grand Master

Joined: Tue Oct 09, 2007 1:55 pm
Posts: 8219
Location: New Forest, UK
Rings are interchangeable 8 to 9.

Even cassettes have the same thickness cogs, so you can dismantle them and reuse 8s spacers. This only works on the cheaper stuff where there aren't the fancy cog carriers.


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PostPosted: Fri Mar 27, 2009 12:16 pm 
King of the Skip Monkeys
King of the Skip Monkeys
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Joined: Wed Nov 07, 2007 4:34 pm
Posts: 26174
Location: Moomin Valley
My personal findings after years of faffing:

Rear mechs: anything Shimano from about 1988 will work on a 9 spd cassette with a 9spd chain

Front mechs: tricky, different mechs require different amounts of pull from the shifter - requires 'fettling'.

Chainsets: chainline can be an issue if the wrong BB spindle lenght is used, then you can get chainline issues but thats about it. A 9 spd chain runs perfectly well on 1987 biopace rings.

Just make sure you use a 9spd chain for 9spd cassettes, then there'll be no tears.

9spd chains shift perfectly well with 6/7/8 spd cassettes.


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PostPosted: Fri Mar 27, 2009 12:34 pm 
Retro Guru

Joined: Thu Nov 01, 2007 1:36 pm
Posts: 930
Location: Sussex
I run early '90s 8-spd everything with a modern 9-spd front chainset/rings. Works great.


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PostPosted: Fri Mar 27, 2009 8:23 pm 
Retro Guru

Joined: Tue Mar 24, 2009 6:10 pm
Posts: 939
Location: Kent,25 miles from France
Thanks chaps.

I still run 8 speed XT on the Karakoram. Buts as time goes on getting XT cassettes (well 30-11's) is getting harder. IG70 chain is still easilable available, but front mechs are getting harder as are cranksets. I remember that in 1999 there wasa lot of talk about people changinging their 8sp casettes to 9 speed along with 9sp chain, shifters and cranks.Then finding that the cassettes didn't fit :cry:

One day I may have to fit a 9sp compatable crankset and or mechs. But for the time being I have just enough 8sp spares !

However, my 7 sp specialised hardrock still shifts better than any 8sp I've ever riden........... :oops:


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PostPosted: Fri Mar 27, 2009 8:41 pm 
retrobike rider
retrobike rider
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Joined: Fri Aug 08, 2008 2:36 pm
Posts: 16748
Location: Yorkshire, England
I have a SLX front chainset (mega9), XT M971 front mech (latest one mega9), XT M737 Casette (compact 8 speed 11-28 I think, first compact they did) on a M900 hub (so I must have spacered it to fit the 11 tooth) and a XT shadow rear mech. All driven with a KMC 8 speed chain and shifting with GripShift SRT-500R (8 speed and early 90's)
Work excellenty at the rear, I find increased chainrub on the front mech but probably as I'm using an 8 speed chain and I would assume they are optimised for a narrow 9 speed chain to get the best out of that, the Gripshift have intermediate steps so it's not really a problem.

For me it purly the front mech that seems to be the weekest link, as ring diameters dropped to compact dimensions they had to change it's curve. As chains narrow they have to alter the shifting plates to that thickness.


Quick look and CRC do an SRAM 11-30 8 speed cassette


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