Advertise on Bikeforums.net



User Tag List

Results 1 to 9 of 9

Thread: Rake distance.

  1. #1
    Senior Member Adam G.'s Avatar
    Join Date
    Aug 2008
    Posts
    532
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Rake distance.

    When you hear someone say less rake does that mean the fork is closer to the head tube? Because the geometry on a track bike, you want the fork and wheel as close as possible the head tube for quicker reaction?

  2. #2
    Senior Member
    Join Date
    Aug 2007
    Posts
    95
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    No, it means the fork is closer to leaves raking chain stay arch bridge.

  3. #3
    Senior Member Bacchusbill's Avatar
    Join Date
    Jun 2006
    Location
    NOLA
    My Bikes
    '00 Bruce Gordon Rock and Road Tour, '01 Breezer Venturi, '97 Specialized Stumpjumper M2 Pro, '87 GT Timberland, '82 Benotto single speed, '48 Schwinn Phantom, '71 Schwinn Pea Picker, '07 BFSSFGIRO
    Posts
    173
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I'm not certain that I understand your question but look at this and ask again...
    Attached Images Attached Images
    "Get a bicycle. You will not regret it if you live." ~Mark Twain

  4. #4
    . bbattle's Avatar
    Join Date
    Aug 2005
    Location
    Huntsville, Alabama
    My Bikes
    2014 Trek Domane 5.2, 1985 Pinarello Trevisio, 1991 Colnago Master, '06 Bianchi San Jose, 1987 Moulton Fuso, '80's Gardin Shred?, '82 John Howard(Dave Tesch)
    Posts
    11,824
    Mentioned
    5 Post(s)
    Tagged
    0 Thread(s)
    Cruiser bikes will often have less rake than a track bike but it's due to their slack headtube angle. Less rake, more trail, for the same angle.

    Then there's the angle of the fork blades to the steerer crown. That angle on a straight bladed fork is often the same created by a fork with curved ends. You end up with the same rake, just different looks.

    So when looking for that ultra twitchy tarck bike, check out the headtube angle. The ultimate of course, being a unicycle.

  5. #5
    the darkness DARTHVADER's Avatar
    Join Date
    Oct 2007
    Posts
    391
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by bbattle View Post
    Cruiser bikes will often have less rake than a track bike but it's due to their slack headtube angle. Less rake, more trail, for the same angle.

    Then there's the angle of the fork blades to the steerer crown. That angle on a straight bladed fork is often the same created by a fork with curved ends. You end up with the same rake, just different looks.

    So when looking for that ultra twitchy tarck bike, check out the headtube angle. The ultimate of course, being a unicycle.
    lol. what?
    are you joking about this?

    slack head angles usually have more rake.
    help.

  6. #6
    . bbattle's Avatar
    Join Date
    Aug 2005
    Location
    Huntsville, Alabama
    My Bikes
    2014 Trek Domane 5.2, 1985 Pinarello Trevisio, 1991 Colnago Master, '06 Bianchi San Jose, 1987 Moulton Fuso, '80's Gardin Shred?, '82 John Howard(Dave Tesch)
    Posts
    11,824
    Mentioned
    5 Post(s)
    Tagged
    0 Thread(s)
    http://davesbikeblog.blogspot.com/20...le-bit-of.html

    http://davesbikeblog.blogspot.com/20...rrelly_30.html

    http://en.wikipedia.org/wiki/Bicycle...cycle_geometry

    In the top two diagrams of the wikipedia link, they have the same rake distance, but the left one has more trail due to the slack head tube angle.

    In the bottom two diagrams, the left one has less rake offset but more trail so it's more stable and easier to ride no hands. The one on the right, with more rake offset, has less trail so will be twitchier and more responsive to ride. All of the forks in these diagrams have the same angle of the fork blades to the steerer tube.


    http://www.phred.org/~josh/bike/trail.html

    "Trail is the distance the contact patch of the front tire lags behind the point where the steering axis intercepts the ground.

    Consider the casters on a shopping cart: the wheels are offset behind the vertical steering axis, and the force of the ground on the wheel tries to center the wheel on the direction of travel.

    The greater the distance between the steering axis intercept and the contact patch, the stronger the centering force becomes.

    For a given steering angle, offsetting the hub forward reduces trail, while offestting the hub backward increases trail. This may seem counterintuitive, since very stable cruiser bikes usually have more fork rake than twitchy track bikes. But the other factor at work is the angle of the steerer -- cruiser bikes have very slack head tubes, so they have more trail despite their fork rake, not because of it.
    Standard road bikes have the hub offset ahead of the steering axis. This can be done several ways:

    By bending the fork blades forward in a curve;
    By offsetting the blades ahead of the steerer tube at the fork crown;
    By offsetting the dropouts ahead of the fork blades;
    By having the blades leave the fork crown at an angle to the steering axis;
    or by any combination of these methods.
    For a given steering angle and fork offset, the trail is the same regardless of how the offset is obtained. A straight bladed fork with 45mm of rake has exactly the same trail as a curved-bladed fork of the same length with 45mm rake. All that matters here is the points at the fork crown and the dropouts, not the shape of the fork between them. "

    "He who laughs last, laughs loudest."
    Last edited by bbattle; 11-21-08 at 08:08 AM.

  7. #7
    Senior Member Adam G.'s Avatar
    Join Date
    Aug 2008
    Posts
    532
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Good looking, bbattle. Sums it up for me.

  8. #8
    the darkness DARTHVADER's Avatar
    Join Date
    Oct 2007
    Posts
    391
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by bbattle View Post
    Cruiser bikes will often have less rake than a track bike but it's due to their slack headtube angle.
    yeah, now read the stuff you bolded in post #6 and tell me what you think.
    help.

  9. #9
    . bbattle's Avatar
    Join Date
    Aug 2005
    Location
    Huntsville, Alabama
    My Bikes
    2014 Trek Domane 5.2, 1985 Pinarello Trevisio, 1991 Colnago Master, '06 Bianchi San Jose, 1987 Moulton Fuso, '80's Gardin Shred?, '82 John Howard(Dave Tesch)
    Posts
    11,824
    Mentioned
    5 Post(s)
    Tagged
    0 Thread(s)
    Gadzooks! I've pwned myself!!!



    I meant to repeat in my first post what I copied on bold on the next post. What a jackass I was.

Posting Permissions

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