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shimano 9 cog on 8 drivetrain?(7 posts)

shimano 9 cog on 8 drivetrain?brownfeesh
Sep 8, 2003 8:36 AM
I have a few wheels with shimano 9cog cassetes. I'm considering buying a bike with an 8cog cassette. If I run a 9 cog cassette with an 8 speed derailer, will it work? I understand it will only be able to shift on 8 of the cogs.
hmmmmlaffeaux
Sep 8, 2003 10:26 AM
If your bike is currently a 9-speed bike, and you buy an 8 speed wheel, you'll need to buy a 9 speed cassette to put on the new wheel, and then it will work fine.

If you install a wheel with an 8-speed casette (8 and 9 speed hubs are the same) on your bike it will not shift. The width of 8 and 9 speeds casettes are the same. Your 9-sped shifters will move the rear derailer 1/9th of the distance of the full cassette with each shift, making an 8-speed casette shift very poorly.
just keep it 8atpjunkie
Sep 8, 2003 12:20 PM
8sp der on 9 speed cog no good. Just leave it. I have 1 8sp and 1 9 speed bike. I prefer the 8 actually. Like last post said 9 speed cog has diff. gaps and a narrower chain to fit. 8 is great, don't fix if it ain't broken
not true!!OffRoadTourer
Sep 11, 2003 7:55 AM
An eight speed derailler will work just fine on a nine speed cassette, the total throw for the derailler is the same for either as both cassettes are the same total width. The chain width difference will not matter because a slightly narrower chain (we're talking fractions of a mm) will still fit through the derailler. The problem is with the shifter not the derailler!

An eight speed shifter will not work with a nine speed cassette (and vice versa) as the spacing between the cogs is different and the shifter will be pulling the wrong amount of cable to move the derailler. The derailler does not determine how far it moves between shifts, that is determined by the shifter.

Whoever told you an eight speed derailler will only access eight of the nine cogs on a nine speed cassette just doesn't understand how a derailler works or the difference between eight and nine speed - plain and simple. Sorry if I sound angry but it really annoys me when people who don't really know something take a wild guess and pass it off as fact, leading to more confusion and misunderstanding.

I have to agree with atpjunkie that eight speed is better. Not because eight speeds are better than nine, but Shimano's durability appeared to become a second priority to weight and cutting edge performance when they made the move to 9 speed. Consequently the nine speed stuff seems to wear out or break more easily. If you ride 9 speed at least get a decent chain (like a Wipperman or high end Sachs/SRAM) and ditch that horrible piece of junk that Shimano try to pass off as a chain. Blah!

Angry spit over, I'll be nice now :)
not true!!atpjunkie
Sep 11, 2003 9:22 PM
My point on chain width was 8 sp chain won't work on 9 sp cassette. And a 9 sp. rear der. works on a 8 sp. cassette. I've never tried the inverse. as far as an 8 sp der. on a nine I'd defer to you as I would never attempt such nonsense.
Why do you call something that works, "nonsense"? (nm)TFerguson
Sep 12, 2003 5:55 AM
Why do you call something that works, "nonsense"? (nm)atpjunkie
Sep 12, 2003 3:03 PM
I like 8 speed for the aforementioned reasons. as a larger rider and a victim of the Shimano 9 speed chain snap I like 8. IMHO the 8 speed XT rear der. was the best ever made by Shimano. Superior to even the XTR of the same era. smooth shifts, reliable, bullet proof. I refer to it as nonsense as why would I switch to 9 if I had an 8 speed set up already. To me that is counter intuitive. Besides the 8 speed is superior in mud. 8 is great, just like chocolate cake.

Mr Luddite

oh yea and I run Campy 9 on my roadies