Advertise on Bikeforums.net



User Tag List

Results 1 to 8 of 8
  1. #1
    Newbie
    Join Date
    Feb 2009
    Posts
    3
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Replacing a crankset on an old Trek

    I wan to get rid of the oval crankset on my 1989 Trek. It has a 52/42 double. I'd like to go with a compact double if possible. Has anyone done this or have any suggestions. I am fine with the downtube shifters and the 7 speed cassette but I need lower gearing.

  2. #2
    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)
    Check your current cranks. They might be drilled for a granny ring. My brother had a Trek from that era with oval rings (SR Ovaltech I think) and the crank was drilled for a granny but run as a double. You might need a longer bottom bracket axle to use as a triple, though. And depending on what you run, you may need a triple specific FD and/or a long cage RD.

    Also measure the bolt hole distance. The crank is probably 130mm (~76.5mm between adjacent holes) but may be 110mm (~65mm). If 110mm, just get new rings (and adjust FD height).

    Otherwise get the compact crank of your choice and bottom bracket to match, install, adjust FD height, and go.

  3. #3
    Your mom
    Join Date
    Aug 2006
    Posts
    2,547
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    You might be able to get that 42 down to a 39 on the current crank.

  4. #4
    Team Beer Cynikal's Avatar
    Join Date
    Apr 2004
    Location
    Sacramento CA
    My Bikes
    Too Many
    Posts
    5,788
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    If its a 130 bcd crank you can go down to 38.
    I'm not one for fawning over bicycles, but I do believe that our bikes communicate with us, and what this bike is saying is, "You're an idiot." BikeSnobNYC

  5. #5
    Senior Member sunburst's Avatar
    Join Date
    Jan 2008
    Location
    NorCal - bay area
    My Bikes
    giant, trek, peugeots, friday
    Posts
    1,305
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by wazzu1991 View Post
    I wan to get rid of the oval crankset on my 1989 Trek. It has a 52/42 double. I'd like to go with a compact double if possible. Has anyone done this or have any suggestions. I am fine with the downtube shifters and the 7 speed cassette but I need lower gearing.

    I have an '86 or '87 Trek 560. This was initially a Shimano 105 equipped bike, with the Biopace double cranks. It sat idle for years. When I started riding it again I did the swap you're considering. It worked out really well, and I'm very happy with the compact. I was able to use the existing FD and RD. I went with a SRAM Rival compact with new bottom bracket on sale at Performance.

    Here's an example I just googled: http://www.amazon.com/Rival-Compact-Crankset-Bottom-Bracketdp/B0011ZGJ08

    I find the big jump in front is perfect for the local terrain with undulating hills. Here's what it looks like.


  6. #6
    Newbie
    Join Date
    Feb 2009
    Posts
    3
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Thanks for the help. Nice bike sunburst. Did you change the cassette and chain as well? If I remember right the hills around SF aren't that different from the one's I'm facing here near Seattle.

  7. #7
    Senior Member sunburst's Avatar
    Join Date
    Jan 2008
    Location
    NorCal - bay area
    My Bikes
    giant, trek, peugeots, friday
    Posts
    1,305
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by wazzu1991 View Post
    Thanks for the help. Nice bike sunburst. Did you change the cassette and chain as well? If I remember right the hills around SF aren't that different from the one's I'm facing here near Seattle.
    I already had the max freewheel I could get on it, a 28tooth. I used the same chain but removed a link or two. I actually like the compact better than the triple that came on my new bike, and I find I can climb some serious hills with the 34/28 combination (and I'm 54!).

  8. #8
    Newbie
    Join Date
    Feb 2009
    Posts
    3
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I talked to the guys at the local bike shop and we decided on a shimano r600. Should be an improvement.

Posting Permissions

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