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8/9 spd. compatability questions.(7 posts)

8/9 spd. compatability questions.latinist
May 8, 2003 10:37 AM
I'm thinking about building up a cx bike using as many of the spare parts I've got lying around. I don't have a ton of $$ to work with so I'd really like to make this work.

I've got a M750 9spd XT rear derailleur which I'm planning on using with an 8spd cassette and prob. a 105 STI lever. This is a single ring setup, too. Should this work Ok? I know I could make the jump to 9spd, but I really want to use the parts I've got. Plus I think 1x8 Frankenbikes are cool as hell.

Any input greatly appreciated, and I'm sorry if this has been answered over and over before.
re: 8/9 spd. compatability questions.latinist
May 8, 2003 10:44 AM
More info:

I recently posted on here saying that I was selling a frame and keeping the parts for the cx build. Well, someone made me a great offer on my Bianchi, so we're going from scratch sort of.

I'll be doing the build on a Salsa Las Cruces frame.
Assuming that the 105 STI you're using is 8spThe Walrus
May 8, 2003 2:15 PM
there won't be a problem. Indexing is in the shifter; the derailleur doesn't care how many cogs there are. My first 'crosser ('99 VooDoo Wazoo) came to me with 8sp 105 STI, 8sp XTR cassette and a 9sp XT mech. Worked flawlessly....
Assuming that the 105 STI you're using is 8spatpjunkie
May 8, 2003 5:01 PM
as long as shifter is 8 you are fine. run 9sp rear der. w/ 8 speed shifters on my MTB. may switch 9 spd cxer to 8 as other cx bike is 8 already. plus I like the 11-30 cassette. Can't get that in 9.
Why not just use a 11-34? Same cogs as 8sp 11-30...TFerguson
May 9, 2003 9:04 AM
plus one extra. I suppose you could even set the derailleur stop to make the 34 unusable.

Why not just use a 11-34? Same cogs as 8sp 11-30...atpjunkie
May 9, 2003 2:48 PM
34 requires longer chain which increases chance of slap drop chain syndrome. Don't need a gear that big for cx, would rather have tighter chainline. I know 12-27 is standard but I'm a Clydesdale and could use a slightly bigger cog. You wouldn't believe how tough it is being over 200. Anyhow I digress, 34 makes too long of a chain and I hate dropping chains. Besides why is it that Shimano 9 goes from 12-27 (Ultegra) to 11-32 or 11-34 (MTB) that's a 5 tooth jump with nothing in between. Campy makes a 13-29, why can't the mighty S? besides I like 8 speed better, I can (and have) break 9 speed chains.
re: 8/9 spd. compatability questions.latinist
May 9, 2003 4:50 AM
Thanks, I'm sure I'll be bugging you again soon.