# What is a 9 / 10 speed bike?



## 6erwebb (Feb 25, 2011)

this has got to be the funniest thing Ive ever had to ask but.. I searched a bit and I think the knowledge is so common no one needs to ask. HOWEVER, I do. Ive ridden and bought bikes for years but never built one. Now Im choosing parts and Im having to decide between 9 or 10 speed stuff.

My bike has 8 speeds on the cassette and the shifter has 8 for the rear cogs and 3 positions for the crank gears. so I need a derailleur and crankset.

SO, what exactly makes up a 9 speed bike? Is it simply 9 rear gears?

Thanks for humoring me, -Webb


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## will-lee wonka (Oct 26, 2008)

yes, you are correct.


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## mimi1885 (Aug 12, 2006)

^^ what he said.
If you only have one ring in the front and 9 cog cassette in the back then you have 9 spd, if you have 3 in the front then you'd have 27 spd but almost half would be overlap, you'd get 13-15 usable gears. 

Though with 10 speed the popular set up is to go with 2 ring in the front less overlapping gears and almost the same usable gears as the tripple.


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## 6erwebb (Feb 25, 2011)

Ah, so when the designation is in question the front gears arent considered? That helps. Thank a bunch guys. I also read somewhere that the 9 speed derailleurs will work with an 8 speed as the derailleur is a "dumb" component. Just does what the shifters tell it. Is that pretty true?


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## mimi1885 (Aug 12, 2006)

Yep, you can use 9spd shifter on 8 spd drivetrain just adj the limiter screw. Same goes to the front as well.


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## 6erwebb (Feb 25, 2011)

Awesome, thanks guys.

-Webb


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## AndrwSwitch (Nov 8, 2007)

Don't buy 10-speed rear derailleurs. With both brands, they're different from the 9-speed and fewer models.


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## will-lee wonka (Oct 26, 2008)

If your current drivetrain is all 8 spd, then you can change the following items to their 9 spd counterparts without a huge amount of issue...the rear der, crankset and front der.

But you should continue to use an 8 spd chain. A 9 spd chain is narrower than an 8 spd chain, so you will experience shifting issues and premature wear as you'll be forcing a narrow 9 spd chain on wider 8 spd cogs on the cassette.

10 spd is a different animal altogether.

Hope this helps.


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## 6erwebb (Feb 25, 2011)

Yeah, I found some quick chain info and decided the 8 speed one needed to stay. I contemplated using the master link on it as well instead of buying a tool but I couldnt find one for an 8 speed chain.

Whats the difference in the 10 speed chain?


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## AndrwSwitch (Nov 8, 2007)

Meh. I've put all sorts of chains on an old 12-speed. It's fine.


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## toiyuet (Dec 23, 2011)

​


6erwebb said:


> Yeah, I found some quick chain info and decided the 8 speed one needed to stay. I contemplated using the master link on it as well instead of buying a tool but I couldnt find one for an 8 speed chain.
> 
> Whats the difference in the 10 speed chain?


I only know Shimano 10 speed chain is more narrow than 8 /9 apeed one.Some of them have different left / right side outer plate shape.


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## thomllama (Oct 3, 2007)

6erwebb said:


> Yeah, I found some quick chain info and decided the 8 speed one needed to stay. I contemplated using the master link on it as well instead of buying a tool but I couldnt find one for an 8 speed chain.
> 
> Whats the difference in the 10 speed chain?


Both Sram and KMC make master links for their 8 speed chains, Shimano is still in the stone ages and doesn't have a masterlink.

the big differences to give you an Idea of what works with what...

8 and 9 speed are basically the same, there is one less click in the shifter but other than that the hardware is the same. 8 speed standard cassette is a tad thicker at the tooth with a slightly wider chain which allows them to use cheaper materials. The 9 speed is a tad thinner. You can use a 9 speed chain on an eight speed drive but you have to adj everything super perfect or as stated above it'll wear really fast and be noisy as hell. To switch from an 8 to a 9 seed you'll need a cassette, shifter and chain that is 9 speed specific. the cranks and front derailleur don't change.

10 speed is different. the cassette's rings are closer together, thus the chain is narrower. but the big diff is the travel of the rear derailleur cage. The parallelogram is slightly different as the cassette has a steeper angle for the cage to move and keep the upper cog within a proper distance to each cassette ring. Plus the shifter is different obviously as it needs 10 clicks/locations and each is a tad less travel than the 9.

this image kinda shows the diff.. look at the red line. There is actually more to it than just that, but this is the main reason a 10 speed derailleur wont work on a 9 speed drivetrain...


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## zebrahum (Jun 29, 2005)

6erwebb said:


> Yeah, I found some quick chain info and decided the 8 speed one needed to stay. I contemplated using the master link on it as well instead of buying a tool but I couldnt find one for an 8 speed chain.
> 
> Whats the difference in the 10 speed chain?


A 10 speed chain is very narrow and shouldn't be used with 8 speed rings and cassettes.

Remember that even if you buy an 8 spd chain with a master link, you still need a chain tool to break the chain to the proper length. Chains are sold to fit the majority of bikes so they're almost always longer than you need them to be. If you run the chain too long, you will have shifting issues or the bike might not even be able to pedal with all the slack.

edit: the Sram PC 890 is a good 8 spd chain with a master link.


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## 6erwebb (Feb 25, 2011)

Ah, sounds like I made the right choice buying the tool then.


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