Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 05-22-11, 05:56 PM   #1
eja_ bottecchia
Senior Member
Thread Starter
 
eja_ bottecchia's Avatar
 
Join Date: Jul 2010
Bikes:
Posts: 3,520
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Shimano Dura Ace 7700 to Dura Ace 7900 upgrade

Quick question...

I have a 2001 Litespeed Classic equipped with a full Dura Ace 7700 group. Someone has offered to sell to me, for a very good price, a full set of Dura Ace 7900 components, brake lever shifters, front and rear brakeset, front and read derailleurs and a 10 sp. casette.

My questions is this, IF I upgrade with the components listed above, do I also have to update the crankset and chain rings (I currently run 53-39 with 170 crank arms).

My friend does not have the DA 7900 crankset/chainring and I kinda prefer the look of the 7700 crankset over the 7900.

So, can I upgrade all the other components and keep the old crankset?

Thanks for any help/suggestions.

BTW, today I saw the last stage of the ToC. I was at the top of the Norwegian Grade (in Thousand Oaks). It was pretty exciting seeing these guy ride up the same hills that I ride on weekends, albeait at a far faster pace.
eja_ bottecchia is offline   Reply With Quote
Old 05-22-11, 06:44 PM   #2
volosong 
Senior Member
 
volosong's Avatar
 
Join Date: Apr 2011
Location: Antelope Valley, SoCal
Bikes:
Posts: 2,718
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Can't help you on the chain question. I'm struggling with my own chain issues.

On the ToC, how fast were they going up the Norwegian Grade? Was it a sprint for them, (since it is a relatively short climb) ... or were they struggling like we do, (because of the steepness)?
volosong is offline   Reply With Quote
Old 05-23-11, 12:38 AM   #3
oldbobcat
Senior Member
 
oldbobcat's Avatar
 
Join Date: Jul 2005
Location: Boulder County, CO
Bikes: '79 Gios, '80 Masi, '06 Felt, early '60s Frejus
Posts: 2,926
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
According to Shimano's compatibility pdf, the 7900 front derailleur requires a 7900 or 6700 crank for optimum performance, but it will also work with older 10-speed cranksets. But 9-speed cranksets/chainrings are out of the question. It also requires an asymmetrical 7901, 6701, or 5701 chain. I don't know if 7900 chainrings will bolt to your 7700 cranks, and even if they do all bets are off on shifting performance.
oldbobcat is offline   Reply With Quote
Old 05-23-11, 01:03 AM   #4
the_don
Senior Member
 
the_don's Avatar
 
Join Date: May 2008
Location: Tokyo
Bikes:
Posts: 1,917
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
If it doesn't have the cranks, then it's not a full set.

Here is some lists of compatibility from Shimano

http://www.starbike.com/images/Shima...ngeability.pdf

http://bike.shimano.com/publish/cont...ty%20Chart.pdf
the_don is offline   Reply With Quote
Old 05-23-11, 08:17 AM   #5
volosong 
Senior Member
 
volosong's Avatar
 
Join Date: Apr 2011
Location: Antelope Valley, SoCal
Bikes:
Posts: 2,718
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Quote:
Originally Posted by the_don View Post
the_don, where does the Shimano R-553, (50/39/30), crankset fit into the scheme? I'm swapping out the "no-name" stuff for Ultegra.
volosong is offline   Reply With Quote
Old 05-23-11, 08:28 AM   #6
Kimmo
bike whisperer
 
Kimmo's Avatar
 
Join Date: Dec 2009
Location: Melbourne, Oz
Bikes: copy/paste links: http://velospace.org/node/36949 http://velospace.org/node/47746 http://velospace.org/node/47747
Posts: 7,099
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Two factors relevant to a crankset's 10spd compatibility:

1. Tooth offset on the rings. NFI whether you can find ones to make it work...

2. Spider thickness. Is that the sound of a milling machine I hear...?
Kimmo is offline   Reply With Quote
Old 05-23-11, 09:41 AM   #7
liquefied
Senior Member
 
liquefied's Avatar
 
Join Date: Aug 2008
Location: San Francisco
Bikes: 1989 Team Miyata, 1989 Miyata 1400, 1989 Miyata 1400, 1986 Miyata 610, 2007 Specialized Stumpjumper Hardtail
Posts: 1,320
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Your old crankset will work fine! I ran a DA 7700 crankset on my bike with an Ultegra 6700 chain and FD, I had no problems and it shifted like a dream.
liquefied is offline   Reply With Quote
Old 05-23-11, 09:55 AM   #8
Kimmo
bike whisperer
 
Kimmo's Avatar
 
Join Date: Dec 2009
Location: Melbourne, Oz
Bikes: copy/paste links: http://velospace.org/node/36949 http://velospace.org/node/47746 http://velospace.org/node/47747
Posts: 7,099
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I suspected this may be the case. As long as the shifter has enough throw and the chain won't fit between the rings, it should work.
Kimmo is offline   Reply With Quote
Old 05-23-11, 10:51 AM   #9
operator
cab horn
 
Join Date: Jun 2004
Location: Toronto
Bikes: 1987 Bianchi Campione
Posts: 28,306
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Man, i'm really getting tired of correcting the magnitude of wrong information on this forum.

We've done this conversion, and have tested various combinations of combining 'old' 10 speed and 'new' 10 speed stuff. The bottom line is that the instant you start mixing things, with the exception of rear derailleurs, you lose performance.

Old 10s crankset on new 10s everything else? Lower performance front shifting than with new 10s cranksets. You also lose the massively stiff large ring that is featured on 7900/6700 systems.

This is what shimano refers to as 'B' compatibility. Most people have no idea how a properly setup, matched drivetrain is able to perform out of the gate. Most people wouldn't know how to setup one for max performance if they were smacked in the face with it.
operator is offline   Reply With Quote
Old 05-23-11, 10:52 AM   #10
operator
cab horn
 
Join Date: Jun 2004
Location: Toronto
Bikes: 1987 Bianchi Campione
Posts: 28,306
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Kimmo View Post
Two factors relevant to a crankset's 10spd compatibility:

1. Tooth offset on the rings. NFI whether you can find ones to make it work...

2. Spider thickness. Is that the sound of a milling machine I hear...?
Yeah, let's also ignore.

Chain design.
Large ring design, pins ramps.

The new 7900 chain is designed to pickup faster and disengage faster on the 7900 specific chain rings for example. That's why the chains are assymetrical. It makes a big performance difference. A properly setup new 10s front shifting is miles ahead of old 10s in terms of performance.

If you have no idea what you're talking about, stop talking. It's called a lie.
operator is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 03:30 AM.