Advertise on Bikeforums.net



User Tag List

Results 1 to 11 of 11
  1. #1
    Senior Member Not the Slowest's Avatar
    Join Date
    Oct 2007
    Location
    Riverdale, NY
    My Bikes
    2002 Seven Axiom
    Posts
    667
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Compatable Upgrade RD Question for my 7 speed Shimano set-up Road bike

    Hi all
    I have a 7 speed Exage RD that I would like to swap out .

    Most likely I will stay with the 7 speed set-up, maybe put on a 8-9 comaptable down the road if it fits.

    Questions:
    Can I use a 8-9 Shimano RD such as a 105 or ultegra back there with the current 7 set-up?
    Could I use a triple 8-9 RD even if I have a double in the front? My reason is that I may want to through a LARGE
    cassette in the back one day.

    Thanks
    Robert
    Not The Slowest, Never The Fastest, even Solo

  2. #2
    Elitist Troglodyte DMF's Avatar
    Join Date
    Jun 2006
    Location
    Dallas
    My Bikes
    03 Raleigh Professional (steel)
    Posts
    6,896
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    You will need a mountain bike RD with a large (I presume you mean something like a 14-34) cassette. Just about any one will do. 105 and Ultegra are road RDs and won't handle cogs that big.
    Stupidity got us into this mess - why can't it get us out?

    - Will Rogers

  3. #3
    Senior Member Not the Slowest's Avatar
    Join Date
    Oct 2007
    Location
    Riverdale, NY
    My Bikes
    2002 Seven Axiom
    Posts
    667
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by DMF View Post
    You will need a mountain bike RD with a large (I presume you mean something like a 14-34) cassette. Just about any one will do. 105 and Ultegra are road RDs and won't handle cogs that big.
    Actually I believe with a long cage RD (triple) you CAN use a 14-34 or similar. The problem is the double rd usually will not go past 28.

    My most important question is what will work on my 7 speed which in anycase is at a 11-23 now
    Robert
    Not The Slowest, Never The Fastest, even Solo

  4. #4
    Senior Member canopus's Avatar
    Join Date
    Mar 2009
    Location
    Kingwood, TX
    My Bikes
    1985 Cannondale SR300, 1985 Cannondale ST400, Gary Littlejohn Cruiser, BMX
    Posts
    1,207
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    If you are talking about friction shifting then yes, a long cage RD will work for you. If you are talking indexing then chances are good it won't work, or it won't work well, so if you want to keep the indexing I would vote to wait until you can replace everything at once with the group you want. In the case of friction, replace what you want to you hearts content.

    I am currently running the following on:
    Campagnolo Veloce front triple (30,42,52)
    Campagnolo Record Triple FD
    Campagnolo Centaur RD mid-cage
    Campagnolo friction downtube shifters
    Sunrace 7 speed - 13,15,16,18,20,22,24
    SRAM PC870 Chain
    Last edited by canopus; 12-18-09 at 11:13 AM. Reason: added info

  5. #5
    Elitist Troglodyte DMF's Avatar
    Join Date
    Jun 2006
    Location
    Dallas
    My Bikes
    03 Raleigh Professional (steel)
    Posts
    6,896
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Not the Slowest View Post
    Actually I believe with a long cage RD (triple) you CAN use a 14-34 or similar. The problem is the double rd usually will not go past 28.
    You are wrong (and so is canopus).

    Cage length has nothing to do with the size cog a RD will handle. Cog capacity is constrained by the parallelogram geometry; the cage constrains only chain wrap capacity. Shimano road RDs - of any cage length - are spec'd to handle up to 27T, but will generally handle up to 30T.

    Any RD will handle 7-speed 11-23. So what's wrong with your Exage?
    Last edited by DMF; 12-18-09 at 11:17 AM. Reason: speling
    Stupidity got us into this mess - why can't it get us out?

    - Will Rogers

  6. #6
    cycles per second Gonzo Bob's Avatar
    Join Date
    Oct 2003
    Location
    Minnesota
    My Bikes
    Vitus Aluminum, DiamondBack Apex, Softride Powerwing 700, "Generic" Ishiwata 022, Trek OCLV 110
    Posts
    1,790
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    If you want to go with a cassette larger than a 30, go with an MTB rear derailer. Road derailers are rated for only 27 or 28 (but they can often be coaxed to run OK on a 30). Earlier this year I put a Shimano Deore RD-M510 MTB "9-speed" rear derailer on my commuting/touring bike and I run 7-speed on that rig. It's been working great and it was only $22.

    Some Shimano MTB rear derailers are low-normal (Shimano calls them RapidRise). I've read they are supposed to shift better but I've never tried one. I think the Deore LX RD-M580 is low-normal.
    Last edited by Gonzo Bob; 12-18-09 at 11:57 AM.

  7. #7
    Senior Member Not the Slowest's Avatar
    Join Date
    Oct 2007
    Location
    Riverdale, NY
    My Bikes
    2002 Seven Axiom
    Posts
    667
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by DMF View Post
    You are wrong (and so is canopus).

    Cage length has nothing to do with the size cog a RD will handle. Cog capacity is constrained by the parallelogram geometry; the cage constrains only chain wrap capacity. Shimano road RDs - of any cage length - are spec'd to handle up to 27T, but will generally handle up to 30T.

    Any RD will handle 7-speed 11-23. So what's wrong with your Exage?
    One Jockey wheel is missing a tooth half of another, but shifts just fine. Its my commuter beater bike and I rather not have to walk home if possible. That said its time for a new chain and cassette. I'm planning on a 12-28 cassette so I figured I would just cover my bases now that the snow is coming and I have time to work on it ...
    Robert
    Not The Slowest, Never The Fastest, even Solo

  8. #8
    Elitist Troglodyte DMF's Avatar
    Join Date
    Jun 2006
    Location
    Dallas
    My Bikes
    03 Raleigh Professional (steel)
    Posts
    6,896
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Jockey wheels are easily replaced and inexpensive. I'm not sure what parts the Exage xxxx requires, but someone here probably does...
    Stupidity got us into this mess - why can't it get us out?

    - Will Rogers

  9. #9
    Senior Member Not the Slowest's Avatar
    Join Date
    Oct 2007
    Location
    Riverdale, NY
    My Bikes
    2002 Seven Axiom
    Posts
    667
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by DMF View Post
    Jockey wheels are easily replaced and inexpensive. I'm not sure what parts the Exage xxxx requires, but someone here probably does...
    I have had the hardest time figuring the size or finding it on theweb.
    Sometimes I have found great RD deals online that it paid to it versus new wheels.
    Robert
    Not The Slowest, Never The Fastest, even Solo

  10. #10
    Senior Member
    Join Date
    Feb 2009
    Posts
    3,974
    Mentioned
    4 Post(s)
    Tagged
    0 Thread(s)
    Put a 105 long cage in case you go for a triple. It will handle a 30t cog. Go for an LX if you think you will go as large as a 34t cog.
    If you want to replace the jockey wheels go to The Third Hand Loose Screws and get the Ultegra 8sp's and they will work.

  11. #11
    Senior Member Not the Slowest's Avatar
    Join Date
    Oct 2007
    Location
    Riverdale, NY
    My Bikes
    2002 Seven Axiom
    Posts
    667
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by davidad View Post
    Put a 105 long cage in case you go for a triple. It will handle a 30t cog. Go for an LX if you think you will go as large as a 34t cog.
    If you want to replace the jockey wheels go to The Third Hand Loose Screws and get the Ultegra 8sp's and they will work.
    Thanks I'll look for a 105 long cage, that will do the job.

    Thanks all
    Robert
    Not The Slowest, Never The Fastest, even Solo

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •