Advertise on Bikeforums.net



User Tag List

Results 1 to 18 of 18
  1. #1
    Senior Member
    Join Date
    Jul 2005
    Posts
    274
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    What would a compatable replacement be for this mid 1990's crank?

    I have a Miyata hybrid c. mid 1990's that probably needs a new crank as it seems pretty warped. All 3 chainrings wobble by the same amount which tells me the crank is warped. The axle is fine. Back in the old days, a hammer would do the trick but this is an aluminum crank.

    Current Crank:

    Exage 300 LX
    (Shimano FC M300)

    with

    Shimano Biopace SG chainrings 28/38/48.

    I've looked at the compatability chart, and the cranks with the same axle dimension requirements don't seem to be available in the main stream retail places I've looked.

    What's current and compatible?
    Last edited by Raleigh71; 02-06-12 at 11:03 AM.

  2. #2
    I let the dogs out AlphaDogg's Avatar
    Join Date
    Apr 2011
    Location
    Denver, CO
    Posts
    1,889
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Biopace chainrings will "wobble" vertically. If you are seeing a vertical wobble, then you don't need a new crank. If you are seeing a lateral wobble, you will.
    http://i736.photobucket.com/albums/x...6at14619PM.jpg
    Quote Originally Posted by rangerdavid View Post
    intellect? we don't need so stinking intellect. this is the 41.
    Quote Originally Posted by eric01 View Post
    And this is why I don't ride aluminum frames... they will explode if I look at it wrong.

  3. #3
    Senior Member
    Join Date
    Jul 2005
    Posts
    274
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Yeah, this is a lateral wobble. Makes the derailleur setting very, very tricky.

  4. #4
    I let the dogs out AlphaDogg's Avatar
    Join Date
    Apr 2011
    Location
    Denver, CO
    Posts
    1,889
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Raleigh71 View Post
    Yeah, this is a lateral wobble. Makes the derailleur setting very, very tricky.
    Are you sure? What part of the derailleur setting is difficult? Height? Or limit screws?
    http://i736.photobucket.com/albums/x...6at14619PM.jpg
    Quote Originally Posted by rangerdavid View Post
    intellect? we don't need so stinking intellect. this is the 41.
    Quote Originally Posted by eric01 View Post
    And this is why I don't ride aluminum frames... they will explode if I look at it wrong.

  5. #5
    Senior Member
    Join Date
    Jul 2005
    Posts
    274
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    The chainring wobbles back and forth so it hits one side or the other of the derailleur cage. If I set it right for the large chainring, then one of the others rubs or vice versa.

  6. #6
    I let the dogs out AlphaDogg's Avatar
    Join Date
    Apr 2011
    Location
    Denver, CO
    Posts
    1,889
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Raleigh71 View Post
    The chainring wobbles back and forth so it hits one side or the other of the derailleur cage. If I set it right for the large chainring, then one of the others rubs or vice versa.
    Well, first of all, the derailleur cage should be positioned 2-3mm above the big chainring... Your description is not making much sense...
    http://i736.photobucket.com/albums/x...6at14619PM.jpg
    Quote Originally Posted by rangerdavid View Post
    intellect? we don't need so stinking intellect. this is the 41.
    Quote Originally Posted by eric01 View Post
    And this is why I don't ride aluminum frames... they will explode if I look at it wrong.

  7. #7
    Senior Member
    Join Date
    Jul 2005
    Posts
    274
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    The front derailleur cage is situated right where it should be on the seat tube, right above the largest chainring.

    When I spin the crank the chainring hits either one side of the derailleur cage or the other it's so warped. If I get it juuuuusssssttt right smack dab in the middle for the largest chainring so it doesn't hit one side of the chainring or the other then the other chainrings hit. Comprendez?

  8. #8
    Bianchi Goddess Bianchigirll's Avatar
    Join Date
    Apr 2009
    Location
    Camp Hill, PA
    My Bikes
    Too many to list here check my signature.
    Posts
    19,027
    Mentioned
    5 Post(s)
    Tagged
    1 Thread(s)
    so if your standing looking down from the top the rings move from side to side as you rotate the cranks right?

    you need to change the bottom bracket too but if your current rings are 28/38/48 most any of the modern compact cranksets should work


    The rings should appear oval rather than round that is what Biopace is all about, check this out http://www.sheldonbrown.com/biopace.html
    Bianchis '87 Sport SX, '90 Proto (2), '91 Boarala 'cross, '93 Project 3, '88 Trofeo, '86 Volpe, '89 Axis, '79 Mixte, '99 Mega Pro XL Ti, '97 Ti Megatube, , '90 something Vento 603,

    Others but still loved,; '80 RIGI, '80 Batavus Professional, '87 Cornelo, '86 Bertoni (sold), '09 Motobecane SS, '98 Hetchins M.O., '09 K2 Mainframe, '89 Trek 2000, '?? Jane Doe (still on the drawing board), '90ish Haro Escape

  9. #9
    Constant tinkerer FastJake's Avatar
    Join Date
    May 2010
    Location
    Madison, Wisconsin
    Posts
    6,029
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Bianchigirll View Post
    so if your standing looking down from the top the rings move from side to side as you rotate the cranks right?
    +1 Lots of confusion on this thread... but I'm pretty sure this is what the OP meant.

    I don't wish to go searching for your crankset, but one important consideration is chainline. Old crankset arms (pre 1990s) were relatively flat. Then in the early 90s MTB chainstays got fatter, bottom bracket spindles got narrower, and the MTB cranksets as a result had/have arms that are "bent." If you try putting an 'old' crankset on a newer MTB you have to use a super long spindle so the arms don't hit the chainstays and as a result the rings are moved very far out and the chainline gets all screwed up. AFAIK, road cranks never went through this transition.

    So if you can't find out what chainline you have/need, it might be worthwhile posting a picture of your current crankset so we can at least try to point you in the right direction. Or take the bike to your LBS. Do you want another triple? Compact double?
    Why "derailer" is the correct way to spell the gear-change mechanism: sheldonbrown.com/derailer.html

  10. #10
    Senior Member Bill Kapaun's Avatar
    Join Date
    Feb 2007
    Location
    Mid Willamette Valley, Orygun
    My Bikes
    86 RockHopper,2008 Specialized Globe. Both upgraded to 9 speeds.
    Posts
    6,519
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Are these bolted or riveted chain rings?

    IF bolted, maybe they aren't seated correctly?

  11. #11
    Senior Member
    Join Date
    Jul 2005
    Posts
    274
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    These are bolted. I'm sure it seated on the square axle shaft.

    Thanks for the info!

  12. #12
    Senior Member Bill Kapaun's Avatar
    Join Date
    Feb 2007
    Location
    Mid Willamette Valley, Orygun
    My Bikes
    86 RockHopper,2008 Specialized Globe. Both upgraded to 9 speeds.
    Posts
    6,519
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    I'm not talking about the axle!
    The "spider" has "ledges" that the ring sits on.
    If there is crud under there for some unbeknown reason, the rings won't be seated flat.

    IF the rings are actually bent, you could spend a bit of time with a hammer and a couple blocks of wood and probably straighten them out.
    You can also lay them on a flat surface and see where the problem actually is and WHERE to tap them.

  13. #13
    Lover of Old Chrome Moly Myosmith's Avatar
    Join Date
    May 2011
    Location
    NW Minnesota
    Posts
    2,537
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Alivio 48/36/26 should fit nicely and comes in several crank lengths. It should make a good crankset for a hybrid and you can get them with or without a lexan chainguard. I've got one on my light touring bike (a 1990 Trek 700) and have been very happy with the performance.
    Lead, follow or get out of the way

  14. #14
    Senior Member
    Join Date
    Jul 2005
    Posts
    274
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Excellent info. Thanks!

    This is just the sort of information I was looking for.

    Another question arises: My spindle length is 122.5 according to the specs, (I haven't measured it) and this crank takes a 113 mm spindle:

    http://www.ebay.com/itm/Alivio-M430-...item3cc0be528d

    Do I need to mess with the bottom bracket? The crank axle ('spindle') is in good shape.

  15. #15
    Bianchi Goddess Bianchigirll's Avatar
    Join Date
    Apr 2009
    Location
    Camp Hill, PA
    My Bikes
    Too many to list here check my signature.
    Posts
    19,027
    Mentioned
    5 Post(s)
    Tagged
    1 Thread(s)
    YES you do. Check FastJake's info in post #9

    Modern cranks are flatter than cranks for when your bike was made so as you see the spindle is much shorter. if you BB has not been serviced since new it is high time to show it some love anyway.

    Did you try removing the crank from the bike and taking off the rings then placing the 'spider' on a flat surface and make sure it is warped? It is doubtful but is possible the issue is the BB or the spindle itself.
    Bianchis '87 Sport SX, '90 Proto (2), '91 Boarala 'cross, '93 Project 3, '88 Trofeo, '86 Volpe, '89 Axis, '79 Mixte, '99 Mega Pro XL Ti, '97 Ti Megatube, , '90 something Vento 603,

    Others but still loved,; '80 RIGI, '80 Batavus Professional, '87 Cornelo, '86 Bertoni (sold), '09 Motobecane SS, '98 Hetchins M.O., '09 K2 Mainframe, '89 Trek 2000, '?? Jane Doe (still on the drawing board), '90ish Haro Escape

  16. #16
    Collector of Useless Info
    Join Date
    Aug 2009
    Posts
    1,186
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)
    Might not need a new BB. I'd try it with the 122.5- it would only put the chainline out an extra 4.5 mm. If the derailleur reaches, then it's all good. If not, then you can buy a shorter BB.

  17. #17
    Constant tinkerer FastJake's Avatar
    Join Date
    May 2010
    Location
    Madison, Wisconsin
    Posts
    6,029
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Raleigh71 View Post
    Do I need to mess with the bottom bracket? The crank axle ('spindle') is in good shape.
    Yes, I'm pretty sure you will. But you can try it first. I have an 'old' crank on a 'new' MTB and I had to use a super long 123mm spindle (old one was 115 I think) to make it clear the chainstays. The chainline is so bad that I cannot use the middle ring with the biggest cog, it actually derails off onto the granny. If you're ok with bad chainline it will probably work, but the best thing to do is to get the correct spindle.

    Also, your crank arms will be much further out than necessary giving you a bad Q-factor or "tread."
    Why "derailer" is the correct way to spell the gear-change mechanism: sheldonbrown.com/derailer.html

  18. #18
    Senior Member
    Join Date
    Jun 2007
    Posts
    1,288
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I would get a new, correct length bottom bracket. IMO the possible aggravation of having remove and install twice outweighs the possible savings of a $20 bb.

Posting Permissions

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