Advertise on Bikeforums.net



User Tag List

Results 1 to 7 of 7
  1. #1
    ukenut Haptown's Avatar
    Join Date
    Feb 2007
    Location
    Nashville, Tn
    My Bikes
    Cannondale F500, Mid 80's Fuji Touring Series III, 1979 Raleigh Sports 3spd, 1995 Schwinn Traveler
    Posts
    107
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Odd Brake Caliper Placement on old Trek?

    I have a friend who has an old Trek 800 series mountain bike (maybe from the '80's?) and it has a set of brake calipers on the rear wheel that are mounted under the chain-stay! Some of you have probably seen this brake design before but I never have. Does anyone have any information about this brake design? It seems a bit odd to me and my friend says that it's a pain in the neck when he rides through mud or snow - the caliper tends to collect the aforementioned like a beaver dam.
    A few chords strummed on an ukulele, enough to please a few others beside yourself, does more good in this world than the combined efforts of all the financiers and politicians that ever lived. - Frank Littig

  2. #2
    Senior Member
    Join Date
    Apr 2006
    Posts
    2,137
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    They take a special brake called a "U" brake that that is different from both cantilevers and V brakes. The bosses are in a different place. The theory with the placement was the chain stays are bigger and stronger than the seat stays. This would give you less brake flex. The problem with them is because of the location they filled up with mud and you ended up with no brakes. Roger

  3. #3
    Senior Member Grand Bois's Avatar
    Join Date
    Mar 2005
    Location
    Pinole, CA, USA
    Posts
    15,082
    Mentioned
    4 Post(s)
    Tagged
    0 Thread(s)
    Just about every mountain bike built in 1987 had them. Those bosses will also take a roller cam brake. I have a Japanese-made Peugeot with the rear brake under the chainstays. It had a Suntour roller cam, but I switched to a Capagnolo Euclid U brake. The brake won't get clogged so badly if you run a fender all the way through it.


  4. #4
    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
    6,754
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    As mentioned, they are U brakes.
    Common from about 87-89.

  5. #5
    Senior Member
    Join Date
    May 2008
    Location
    SoCal
    Posts
    1,247
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    gack....bike brakes from hell. Clog with mud....they attracted mud like Trailer parks and Tornados

  6. #6
    feros ferio John E's Avatar
    Join Date
    Jul 2000
    Location
    www.ci.encinitas.ca.us
    My Bikes
    1959 Capo; 1980 Peugeot PKN-10; 1981 Bianchi; 1988 Schwinn KOM-10;
    Posts
    14,632
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)
    My mountain bike (see signature) has an under-chainstay U-brake and a RollerCam in front. Yes, the rear brake does tend to pick up dirt, but the brakes provide me plenty of easily modulated stopping power. Yes, I would have preferred a more conventional location for the rear brake, but the system I have is not bad.
    "Early to bed, early to rise. Work like hell, and advertise." -- George Stahlman
    Capo [dschaw'-poe]: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger, S/N 42624
    Peugeot: 1970 UO-8, S/N 0010468
    Bianchi: 1981 Campione d'Italia, S/N 1.M9914
    Schwinn: 1988 Project KOM-10, S/N F804069

  7. #7
    Senior Member
    Join Date
    Nov 2004
    Posts
    9,997
    Mentioned
    4 Post(s)
    Tagged
    1 Thread(s)
    There's is another reason for the lack of flex of the U-brake. The mounting studs are are above the rim, as opposed to below it, as in cantilevers or V-brakes. With the studs farther up the stays and closer to the bridge, the stays are more resistant to outward flex in response to braking force.

    There was another advantage to the U-brake. Early ATBs had very long chainstays. By the late 1980s, these had shortened considerably and the geometry become more agressive in general. With ther shorter stays, some riders would contact the cantilvers with their heels, dislodging the yoke cable and resulting in no brake. The narrow profile of the U-brake prevented this.

    U-brakes are still common on BMX bicycles.

    My 1988 GT Karakoram had the best of both worlds. It had a rear U-brake that was mounted on the seat stays.

Posting Permissions

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