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Discussion Starter · #1 · (Edited)
I have a Cervelo Prodigy w/ Ultegra group and want/need to convert from double to triple. What do I need to change?

On the shimano site it looks like i can convert the rear derailleur by changing the cage and spring (ss to gs). It also looks like the shifters will work as is. Shimano doesn't list it but colorado (or nashbar, i can't remember) seems to have a bottom bracket with the same model number but a few mm longer for the triple - is this needed?

So i guess it looks like i can do it with new cranks and rear cage. Anything else? Oh yeah - front derailleur too i guess.

Thanks for your help.

Jim

(BTW - have there been any spline changes from 2001 to now on the ultegra line?)
 

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triple

Complete crank-set and bottom bracket. It would be better to replace both derailleurs but you can make it work with the old rear derailleur if you stay out of the small chain ring with small side of the cassette combinations. You might even make the old front derailleur work but I would not try that. Be sure to have enough chain to wrap the big to big combination without bottoming out the rear derailleur. You may or may not need to add chain.
~Al
 

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Discussion Starter · #3 ·
Thanks Al

Al1943 said:
Complete crank-set and bottom bracket. It would be better to replace both derailleurs but you can make it work with the old rear derailleur if you stay out of the small chain ring with small side of the cassette combinations. You might even make the old front derailleur work but I would not try that. Be sure to have enough chain to wrap the big to big combination without bottoming out the rear derailleur. You may or may not need to add chain.
~Al
Thanks Al - I forgot the chain.

I will try the retrofit on the rear due to the exploded view by shimano that shows it being identical minus the changes in the cage. Now I just have to find parts and make sure I get the right bb.

Will there be any need for additional cable length in the front der. control cable?

Jim
 

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retrofit

JimGR said:
Thanks Al - I forgot the chain.

I will try the retrofit on the rear due to the exploded view by shimano that shows it being identical minus the changes in the cage.
It's really not worth the expense and effort, considering the short cage will work.Just size the chain big/big and stay out of the smaller cogs when in the granny,which there is no point to anyway.
 

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consider a 53/39/30

When it comes to triples, a 53/39/30 allows you to use the little ring less often and gives you the same gear ratios that you buddies have with their 53/39 doubles. It also provides a more uniform gearing progression with a 2-cog shift after every chainring shift.

The 53/39/30 is only available in a DuraAce level Shimano crank. FSA makes a cheaper Energy crank ($150) with a 53/39/30. The Energy crank comes in both ISIS and Shimano octalink versions. The 53/39/30 crank might require a DuraAce level front derailleur for the best shifting with Shimano STI levers.

Shimano rear derailleurs are so inexpensive that the replacement parts might cost a large portion of the cost of an entire new derailleur, so a new RD might be a better value.

Anyone selling you a new crank should have the correct BB to go with it. An Ultegra triple for instance, take a 118mm spindle length.

The idea of using the old short cage derailleur is questionable, unless you only want the triple for an occasional bailout on a hill. If you set the chain length for the big-big combo, you will only be able to use the largest two or threes cogs with the little ring and then you'll have a slack chain.

I ride in the mountains and want the full use of my cogs with the little ring. Once I'm on a mountain, I get into the little ring and stay there until I get to the top. I need more than just the last two or three cogs to avoid constant shifting between the middle and little rings.
 

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C-40 said:
The idea of using the old short cage derailleur is questionable, unless you only want the triple for an occasional bailout on a hill. If you set the chain length for the big-big combo, you will only be able to use the largest two or threes cogs with the little ring and then you'll have a slack chain.

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Not always true, and it depends on the front rings and cassette cog spread. Wrap spec is also usually conservative. I have a SC on a 52/39/ 30 with a 13 x23 rear and it will wrap all the chain even in the small/ small. A ultegra front shifter also works fine with a 39 middle ring and I believe there are pinned and ramped 39s available from Peter White Cycles. Even if the 39 is unramped, it still shifts good enough for all but the most AR.
 

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Compact Option

You might be able to save some bucks if you go with a compact crankset with chainrings in the 50/34 range. You should be able to compare the options over at Sheldon Brown's gear inch calculator. If you got an AL octalink crankset (I know FSA is supposed to have a model out in March, and there are other makers out there) you wouldn't have to change any other parts, and you'd get almost the full gear range of a triple.

JimGR said:
I have a Cervelo Prodigy w/ Ultegra group and want/need to convert from double to triple. What do I need to change?

On the shimano site it looks like i can convert the rear derailleur by changing the cage and spring (ss to gs). It also looks like the shifters will work as is. Shimano doesn't list it but colorado (or nashbar, i can't remember) seems to have a bottom bracket with the same model number but a few mm longer for the triple - is this needed?

So i guess it looks like i can do it with new cranks and rear cage. Anything else? Oh yeah - front derailleur too i guess.

Thanks for your help.

Jim

(BTW - have there been any spline changes from 2001 to now on the ultegra line?)
 

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Discussion Starter · #10 ·
C-40 said:
The idea of using the old short cage derailleur is questionable, unless you only want the triple for an occasional bailout on a hill. If you set the chain length for the big-big combo, you will only be able to use the largest two or threes cogs with the little ring and then you'll have a slack chain.
I think you're right - if nothing else, in case I were to shift accidently in the small-small direction. I'm still checkiing on parts and if I can convert for $25 or less I'm going to do it.
 
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