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covert a 18 speed road bike to a 20 speed.

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covert a 18 speed road bike to a 20 speed.

Old 07-05-12, 11:02 AM
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covert a 18 speed road bike to a 20 speed.

9 speed cassette. chain is worn and I need to replace that and prob the cassette. Is there a way to use the current derailure that I have or are they 9 speed or 10 speed specific? What all would I have to replace on the 18 speed to convert it to 20?
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Old 07-05-12, 11:39 AM
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Replace worn parts with fresh ones without distraction by marketing.

'Speed' is work applied by rider, you wont be faster with 1 more cog.

it will hoover up a lot more money.

I'd buy a whole new bike if you Have To have the hot new 'thneed'.
the parts needed to convert will be almost as much.
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Old 07-05-12, 11:46 AM
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You will need new 10 speed specific parts. Shifters/brifters, chain, cassette at minimum. Possibly a front derailleur, not sure if the narrower chain makes a difference between 9 and 10 speed. 10 speed specific parts are quite a bit more money than 9 speed specific parts.

Pretty cheap to do if you enjoy burning money in a fire pit with no real gain in real world feel.
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Old 07-05-12, 11:49 AM
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I agree. Trying to 'upgrade' your bike from a workable 9X2 to a workable 10X2 will cost much much more than the value of the benifit you will get. What exactly are you hopoing to accomplish with this change?

If you have a Shimano drivetrain, and you are intent on doing it, you will need 10 speed shimano road shifters, a 10 speed shimano compatible chain, and a 10 speed shimano copatible cassette. There is no need to change the derailleurs as 9 speed SHaimno derailleurs are compatible with 10 speed shimano road components.

If you go with bar-end or downtube shifters (or friction shifters) then the whole project can be done for > $200. If you want STI/Brifters, the price is much more.

If you have 9 speed Campagnolo components then I have no idea what you need.
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Old 07-05-12, 12:00 PM
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Originally Posted by DCB0
If you go with bar-end or downtube shifters (or friction shifters) then the whole project can be done for > $200. If you want STI/Brifters, the price is much more.

If you have 9 speed Campagnolo components then I have no idea what you need.
It depends. First generation (pointy hood) ergo levers must be replaced, although if you settle for escape levers that are crippled with Shimano-like one cog smaller behavior that can be done for $85 from your favorite UK retailer including a cable set. Index cams are available for second generation (round hoods) levers. 2000 and older derailleurs (conventional B-tension adjustment) must be replaced because the pull ratio changed with the move to 10 speeds. 2001 and newer 9 speed derailleurs (tension adjustment on lower pivot) are fine (they got the new pull ratio).

I wouldn't do it unless you've worn out parts like your shift levers and rear derailleur.
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Old 07-05-12, 12:12 PM
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I'd leave it. 9-speed cassettes will continue to be available for a long time.
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Old 07-05-12, 12:14 PM
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Heh, when I clicked on this thread, I figured the OP had a 3x6 bike.
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Old 07-05-12, 01:07 PM
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It would help us offer better advice if we knew what kind of shifters and derailleurs you have now and what kind you would want to use with a 10-speed rear. There may be some compatibility issues.
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Old 07-05-12, 01:52 PM
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hey thanks a lot guys. ill take your advice and just grab a new cassette and chain.

What is the best way to judge how warn a cassette is?

I know I need a new chain because my chain wear tool fits in even on the largest wear side. I have read that usually u replace the cassette and the chain at the same time because they wear together. is this correct? I have also heard people say to buy 2 chains and switch them out every month or so to get more chain life without having to switch the cassette. Is this a good idea?
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Old 07-05-12, 02:33 PM
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Originally Posted by Homebrewevolver
hey thanks a lot guys. ill take your advice and just grab a new cassette and chain.

What is the best way to judge how warn a cassette is?
When a new chain skips.

I know I need a new chain because my chain wear tool fits in even on the largest wear side.
That also includes roller diameter tolerances and wear which don't affect cassette wear like elongation does.

You're usually better off using a 15" ruler and just measuring between the same part of pins that are supposed to be 12" apart. Replace the chain when you get to 1/16" of elongation.

I have read that usually u replace the cassette and the chain at the same time because they wear together. is this correct?
No. The tiny little pins and holes they rub directly against in the thin inner chain plates generally wear much faster than the big teeth on the thick cogs where the chain rollers rotate on and off.

I think I ran 4 chains on my last cassette. I may have been able to run a new chain if I wasn't replacing a worn-out derailleur, worn-out shift lever, and moving to 10 cogs at the same time.

I have also heard people say to buy 2 chains and switch them out every month or so to get more chain life without having to switch the cassette. Is this a good idea?
Three would be better. People also have success rotating chains much less frequently, like every 2500 miles.

The idea is that you use all the chains you're ever going to with the cassette. Since you rotate between them they're all elongating at the same rate and mate about the same with the cogs. Eventually they get to the point where the change in pitch is causing significant wear on the cogs which would preclude them from mating to a new chain; although that doesn't matter since all the chains are stretched enough to mate well.

Some people scrap chains and cassette at that point and it still makes sense as an insurance policy where if something abnormal happened to chain and cassette wear you still get the full ~15,000 miles out of the cassette.

Some people keep going at that point until something else bad happens like skip.

I suspect that's not the best idea since the increased chain pitch is also likely to wear the rings which can cost more than the chains you're not buying, especially with nice Shimano or Campagnolo rings.

Last edited by Drew Eckhardt; 07-05-12 at 06:45 PM.
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