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Recent content by 2SlowJoe

  1. 2SlowJoe

    LCA angle towards rear question

    mvf4sp, That is what is being discussed here. I agree with your analysis. The plan view angle of the control arm pivot axis will effect the F/A motion of the wheel center with vertical wheel travel. The SVSA concept is a visualization tool that helps a person see the motion of...
  2. 2SlowJoe

    LCA angle towards rear question

    dfoxengr, The rate of change of Side View Swing Arm Angle (SVSAA) definately is effected by the F/A path of the upper and lower ball joints. The F/A path of those joints is effected by the plan view angle of the control arm pivot axis. I did use a little symbol speak when I said SVSAA, and...
  3. 2SlowJoe

    LCA angle towards rear question

    The plan view angle of the LCA inner pivots will effect the rate of change of SVSAA. If the inner pivots were located in the same line laterally, the F/A motion of the LBJ with vertical travel would be a straight line perpendicular to the side view inclination of the inner pivot axis. By...
  4. 2SlowJoe

    Suspension Topologies for ultra luxury vehicles

    Looking to know a little more about ultra lux suspension topologies, and my usual sources (autoreverse, etc) have come up relatively dry. Does anyone here know what suspension topologies (front and rear) are used by the following manufacturers: Maybach Rolls Royce Bentley Since there are...
  5. 2SlowJoe

    Brake Mounting location

    Mounting the caliper at the front or back rather than the top or bottom can help reduce "knockback". Under cornering loads, the wheelbearing flexes which causes the rotor to be at an angle relative to the pads. This spreads the caliper. The next time the brake is applied, their is a dead...
  6. 2SlowJoe

    The SAE coordinate system

    Also forgot to mention one other thing: Primary understeer works in the linear range, and at the limit. Secondary understeer will not work at the limit. Once you write a check the tires can't cash, roll steer or compliance steer will do nothing. -Joe
  7. 2SlowJoe

    The SAE coordinate system

    I think you are getting at the difference between what Olley called “primary understeer” and “secondary understeer”. They are both understeer, but they work in different ways. Primary understeer affects not only the steering wheel angle, but also the slip angles at the tires. It is controlled...
  8. 2SlowJoe

    Question about GM "Skateboard" chassis concept

    It uses an SLA with a transverse leaf. The leaf is not used as an arm. (similar to C5 and C6 Corvette) -Joe
  9. 2SlowJoe

    Lower control arm position

    The relative angle betweeen the upper and lower control arm controls the slope of the camber curve. The relative length of the upper to lower control arm controls the curviture of the camber curve. You can have no change in camber with parallel, but not horizontal, upper and lower control arms...
  10. 2SlowJoe

    Determining ball joint rate

    The spring rate would be the wheel rate (or ball joint rate) times the linkage ratio squared. The spring load would be the wheel load - unsprung times the linkage ratio. -Joe
  11. 2SlowJoe

    Roll Steer Plot

    Another thing... If this was a front suspension things get even more complicated since the left side is linked to the right through the steering system compliance. With rack compliance, a net rack force will cause a steer effect. Anything that could put a moment about the kingpin can cause a...
  12. 2SlowJoe

    Important suspension parameters

    Ride Steer and Roll Steer Ride Camber and Roll Camber Side View Swing Arm Angle (SVSAA) Lateral Stiffness (at ground w/o tire) Fore-Aft Stiffness (at wheel center w/o tire) Lateral Force Camber Compliance Tractive Force Steer Brake Force Steer
  13. 2SlowJoe

    Roll axis inclination

    What side view roll axis inclination do you guys usually target and why? Here are some observations: The inclination of the roll axis effects the roll-yaw coupling. Having the axis inclined so that it goes up as it goes rearward causes the body to yaw out of the turn as the body rolls. The...
  14. 2SlowJoe

    Roll Steer Plot

    Many people assume that for an independent suspension, the plot of toe vs wheel center travel that results from a ride event is the same as the one that results from a roll event, or a single wheel event. This assumption assumes that the left side of the vehicle is independent of the right...

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