Math me please

Discussion in 'BearClaw Corner' started by Claviger, May 13, 2018.

  1. Claviger

    ClavigerHP Junkie extraordinaire

    Messages:
    4,791
    Featured Threads:
    111
    Media:
    69
    Likes Received:
    5,601
    Trophy Points:
    823
    Location:
    Olympia Washington
    Ride:
    '14 R3R, '02 Daytona 955i
    @1olbull or others who are good at geometry (I'm terrible at it). I am trying to mentally digest some lean angle stuff. Basically, why do I have to lean so much more on my R3 for a given speed than smaller bikes. A few things are obvious
    1: Wheelbase
    2: Tire width
    3: Steering Geometry

    So from what I've read:

    1: Wheelbase, effects mostly transitional states, and has a very minor effect in steady state cornering. While the tangent drawn through the axles to center of the circle of a turn will be slightly greater on a longer wheelbase bike, the effect is small.

    2: Tire width, from what I've read, has the most effect on steady state cornering lean angle. If that's the case, then a larger tire would need to be leaned over more to track around the same radius curve as a narrower tire, however, the wider tire will simultaneously have a larger contact patch while doing so. The greater contact patch will translate to some increase in traction, providing the ability to lean even further until you touch hard parts down. Alternatively, it would allow throttling out harder and earlier than the narrow tire bike, provided, the increased speed still allows you to stay on a radius that will complete the corner.

    3: From what I've read, this has basically no effect on lean angle during steady state cornering, but instead only effects transient action.

    Putting that all together, is there a way to calculate what the theoretical (combined rider + bike) lean angle would be for a given turn if you know the geometry numbers and radius of the turn, for example the one below at 75mph?

    Highway 2 Sweeper.png
     
  2. Claviger

    ClavigerHP Junkie extraordinaire

    Messages:
    4,791
    Featured Threads:
    111
    Media:
    69
    Likes Received:
    5,601
    Trophy Points:
    823
    Location:
    Olympia Washington
    Ride:
    '14 R3R, '02 Daytona 955i
    To add to the conundrum, center of gravity.

    The CoG for the R3R seems to be incredibly low, and I’m wondering if that might be the primary contributor of the required deep angles at speed.

    If that’s correct then it would explain why hanging off the bike helps, but doesn’t contribute to the same level as doing so on a sportbike.
     
  3. BigNorm

    BigNormBoobie Inspector

    Country:
    United States
    Messages:
    2,879
    Featured Threads:
    23
    Likes Received:
    3,387
    Trophy Points:
    823
    Location:
    Minden, NV, USA
    Ride:
    2014 Rocket 3 Touring
    Norm, Steel, and Steve all have one donut. How many donuts did Norm eat?
     
    thorin, BillyIndiana, Tripps and 3 others like this.
  4. TXtriple

    TXtripleSIC VIS PACEM PARA BELLUM

    Country:
    United States
    Messages:
    49
    Featured Threads:
    1
    Likes Received:
    115
    Trophy Points:
    43
    Location:
    Central Texas Hill Country
    Ride:
    2012 Roadster 2008 Classic
    I think it has more to do with weight and center of gravity. You're fighting the centrifugal force that wants to throw the weight to the outside.
     
  5. Neville Lush

    Neville Lushwww.nevillelushracing.com

    Country:
    Australia
    Messages:
    648
    Featured Threads:
    7
    Likes Received:
    1,490
    Trophy Points:
    103
    Location:
    Victor Harbor South Australia
    Ride:
    Speed Triple 1050 Dirt Track sidecar,H2750Roadrace sidecar W800 Kawasaki
    It's because the wheelbase is longer. Just lean it until it scrapes then pick it up a touch :)
     
  6. gR3yWolf

    gR3yWolfSupercharged

    Country:
    United States
    Messages:
    229
    Featured Threads:
    3
    Media:
    2
    Likes Received:
    185
    Trophy Points:
    53
    Location:
    Johnstown, PA
    Ride:
    '07 Classic
    Interesting reading that may give insight into your question. Probably due more to rake/trail angle sport bike versus Rocket.
     
    Last edited: May 13, 2018
  7. Claviger

    ClavigerHP Junkie extraordinaire

    Messages:
    4,791
    Featured Threads:
    111
    Media:
    69
    Likes Received:
    5,601
    Trophy Points:
    823
    Location:
    Olympia Washington
    Ride:
    '14 R3R, '02 Daytona 955i
    I’m trying to figure out what to adjust/modify, to lessen required angle if possible.

    As it is, I don’t scrape pegs even on the edge of the tire as a result of the mods I’ve made.

    I’m happy with how it does, just wondering what would move it another step forward in mid corner speed. I do know I’m getting over to right around 45 degrees from video review before my internal sensors start screaming at me to stop lol.

    Guess it’s just the 65” wheel base vs a 55” on a modern super sport.l like you say Nev.
     

    Attached Files:

    Last edited: May 13, 2018
    phar2slo likes this.
  8. Claviger

    ClavigerHP Junkie extraordinaire

    Messages:
    4,791
    Featured Threads:
    111
    Media:
    69
    Likes Received:
    5,601
    Trophy Points:
    823
    Location:
    Olympia Washington
    Ride:
    '14 R3R, '02 Daytona 955i
    That’s what I thought, and it certainly helps that I’ve a lot less Trail than stock for agility but the reading I’ve been doing indicates that only effects transient movement.
     
  9. gR3yWolf

    gR3yWolfSupercharged

    Country:
    United States
    Messages:
    229
    Featured Threads:
    3
    Media:
    2
    Likes Received:
    185
    Trophy Points:
    53
    Location:
    Johnstown, PA
    Ride:
    '07 Classic
  10. Claviger

    ClavigerHP Junkie extraordinaire

    Messages:
    4,791
    Featured Threads:
    111
    Media:
    69
    Likes Received:
    5,601
    Trophy Points:
    823
    Location:
    Olympia Washington
    Ride:
    '14 R3R, '02 Daytona 955i
Loading...
  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice