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Old 12-30-04, 07:34 AM   #1
starcon77
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Dura Ace triple to double change over

I have a 2004 Dura Ace triple set-up and want to convert over to a double.

I know that the bottom bracket must be changed since it is longer that the one for the double. However, what other parts must be replaced:

Part Replacement
1) Shifter/brake pods - I am not sure
2) Cranks/Chain Rings - I think that they are the same except for the middle ring which accepts the bolt on for the third chain ring.
3) Bottom Bracket - Must be replaced
4) Front Derailleur - I am not sure
5) Rear Derailleur - I think they are the same
6) Cassette - Same

Thanks for your help and if you see something I missed please let me know.
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Old 12-30-04, 08:24 AM   #2
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Quote:
Originally Posted by starcon77
I have a 2004 Dura Ace triple set-up and want to convert over to a double.

I know that the bottom bracket must be changed since it is longer that the one for the double. However, what other parts must be replaced:

Part Replacement
1) Shifter/brake pods - I am not sure
2) Cranks/Chain Rings - I think that they are the same except for the middle ring which accepts the bolt on for the third chain ring.
3) Bottom Bracket - Must be replaced
4) Front Derailleur - I am not sure
5) Rear Derailleur - I think they are the same
6) Cassette - Same

Thanks for your help and if you see something I missed please let me know.
The shifters will shift a double. You cannot use a regular 130 bcd small ring to replace the DA triple middle ring,as the crank arms are machined differently. You need a new crank. You need a matchng BB for new crank. Or, you could just keep the crank, remove the granny ring and use a 109.5 octalink BB.Your triple derailers will work with a double, but a double FD will work better. I'd just save some money and simply block the shift to the granny ring with the limit screw.
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Old 12-30-04, 09:21 AM   #3
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Quote:
Originally Posted by starcon77
I have a 2004 Dura Ace triple set-up and want to convert over to a double.

I know that the bottom bracket must be changed since it is longer that the one for the double. However, what other parts must be replaced:

Part Replacement
1) Shifter/brake pods - I am not sure
2) Cranks/Chain Rings - I think that they are the same except for the middle ring which accepts the bolt on for the third chain ring.
3) Bottom Bracket - Must be replaced
4) Front Derailleur - I am not sure
5) Rear Derailleur - I think they are the same
6) Cassette - Same

Thanks for your help and if you see something I missed please let me know.
I'm just purely curious...why?

The benifits of a double are better shifting due to a shorter chain, shorter rear derailleur cage, and cleaner shifting in the front due to a purpose built front derailleur. It seems to me that you would have to replace just about everything to get all the the benifits of going to a double, otherwise, you've just got a triple, with the disadvantages of a triple, only you dont have the ability to bail out if the hill gets too steep. seems silly to me.

I wasnt aware that you could use the triple STIs for a double on dura ace. I thought that was only ultegra and lower? I suppose its like using a 7 speed cassette on an 8-speed system--the 8th click is held back by the limit screw? Interesting.
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Old 12-30-04, 09:30 AM   #4
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Originally Posted by Phatman
I'm just purely curious...why?

The benifits of a double are better shifting due to a shorter chain, shorter rear derailleur cage, and cleaner shifting in the front due to a purpose built front derailleur. It seems to me that you would have to replace just about everything to get all the the benifits of going to a double, otherwise, you've just got a triple, with the disadvantages of a triple, only you dont have the ability to bail out if the hill gets too steep. seems silly to me.

I wasnt aware that you could use the triple STIs for a double on dura ace. I thought that was only ultegra and lower? I suppose its like using a 7 speed cassette on an 8-speed system--the 8th click is held back by the limit screw? Interesting.
A double does NOT use a shorter chain. A da triple shifter will obviously shift a double. And yeah, you only use the granny and middle ring shifter positions and the shift to the non existant big ring IS blocked by the limit screw, just like when using an ultegra, 105, or tiagra shifter with a triple. You couldn't tell the difference betwen a long and short cage RD.
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Old 12-30-04, 12:18 PM   #5
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Once you remove the granny, you will find that unexpected 18% grade on your route. Is this a weight thing? Are you riding it, or weighing it?
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Old 12-30-04, 12:39 PM   #6
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Quote:
Originally Posted by starcon77
I have a 2004 Dura Ace triple set-up and want to convert over to a double.

I know that the bottom bracket must be changed since it is longer that the one for the double. However, what other parts must be replaced:

Part Replacement
1) Shifter/brake pods - I am not sure
2) Cranks/Chain Rings - I think that they are the same except for the middle ring which accepts the bolt on for the third chain ring.
3) Bottom Bracket - Must be replaced
4) Front Derailleur - I am not sure
5) Rear Derailleur - I think they are the same
6) Cassette - Same

Thanks for your help and if you see something I missed please let me know.

How much are you selling your old crank for?
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Old 12-30-04, 02:08 PM   #7
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This is so true... now people are talking like they like a triple...

I have a double with a granny gear triple like the dura ace. Due to this I run a smaller (11-23) cassette vs the 12-25 or 12-27 you run with a double. I rarely have to drop to the granny gear even with the 11-23. You should only do this if you have not used the granny gear or else it does not make since...
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Old 12-30-04, 05:39 PM   #8
starcon77
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Thanks for your help. I think what I have in mind will now work.

Steve
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Old 12-30-04, 05:47 PM   #9
starcon77
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I have a 2004 LOOK 386i, after 7,000+ miles this year the cassette and chain rings have some teeth that have a ridge on the face that drives the chain. I posted a picture of the cassette on the road cycling forum with another question. The large chain ring I think has a slight wobble (even after retightening) since the chain scrapes the FD at a certain point in the 360 degree rotation and the chain coming off the middle chain ring sometimes scrapes the inside of the large chain ring. Probably as a result of 1,000 miles on Skyline Drive Mountains and a Bike Tour in the Rockies.

I am going to replace the two larger chain rings and cassette. I also bought a set of Look carbon crank arms. However, the arms will not accept the middle ring with the extra attachment for the small chain ring bolt on. As a result, I am looking at replacing the parts and convert to double to use these arms. Looks like I could always switch back if needed.

Weight is not an issue, the bike is just under 17 pounds (posted pictures under the road cycling what kind of bike do you have? and if I really worried about moving weight I would lose about 5 pounds its cheaper and better for you.
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