PM File troubleshooting

Bill Malicoat

On a dirt mod I have been working on I have a strange issue. The car should have many inches of travel, but even with feet of travel programed in the hdv (rebound) the LF tire comes off the ground with only a few inches of travel onto the RR. This is an oval track so the LF comes off first. Does anyone have any idea why the suspension will not let the rebound of the shock go to its full programmed value?

[BODY]
name=driver_head mass=(7) inertia=(0.035,0.035,0.035)
pos=(0.0,0.0,0.0) ori=(0.0,0.0,0.0)

[BODY]
name=fuel_tank mass=(1) inertia=(1.0,1.0,1.0)
pos=(0.0,0.0,0.0) ori=(0.0,0.0,0.0)

[BODY]
name=body mass=(0) inertia=(0,0,0)
pos=(0,0,0) ori=(0,0,0)

[BODY]
name=fr_wheel mass=(15) inertia=(0.65025608,0.364928,0.364928)
pos=(-0.71,0,-1.1)

[BODY]
name=fl_wheel mass=(15) inertia=(0.65025608,0.364928,0.364928)
pos=(0.71,0,-1.1)

[BODY]
name=rr_wheel mass=(30) inertia=(1.28861415,0.93792,0.93792)
pos=(-0.71,0,1.1)

[BODY]
name=rl_wheel mass=(30) inertia=(1.28861415,0.93792,0.93792)
pos=(0.71,0,1.1)

[BODY]
name=fl_spindle mass=(10.0) inertia=(0.0275,0.0260,0.0245)
pos=(0.6385,0,-1.05) ori=(0.0,0.0,0.0)

[BODY]
name=fr_spindle mass=(10.0) inertia=(0.0275,0.0260,0.0245)
pos=(-0.6385,0,-1.05) ori=(0.0,0.0,0.0)

[JOINT&HINGE]
posbody=fl_wheel negbody=fl_spindle pos=fl_wheel axis=(-1.00,0.0,0.0)

[JOINT&HINGE]
posbody=fr_wheel negbody=fr_spindle pos=fr_wheel axis=(1.00,0.0,0.0)

//Front-Left
[BAR]
name=fl_fore_upper posbody=body negbody=fl_spindle pos=(0, 0.1, -0.8) neg=(0.7, 0, -1.1)

[BAR]
posbody=body negbody=fl_spindle pos=(0, 0.1, -1.1) neg=(0.7, 0, -1.1)

[BAR]
posbody=body negbody=fl_spindle pos=(0, -0.242, -1.1) neg=(0.7, -0.342, -1.1)

[BAR]
name=fl_fore_lower posbody=body negbody=fl_spindle pos=(0, -0.242, -0.8) neg=(0.7, -0.342, -1.1)

//Front-Right
[BAR]
name=fr_fore_upper posbody=body negbody=fr_spindle pos=(0, 0.0, -0.8) neg=(-0.7, 0, -1.1)

[BAR]
posbody=body negbody=fr_spindle pos=(0, 0.1, -1.1) neg=(-0.7, 0, -1.1)

[BAR]
posbody=body negbody=fr_spindle pos=(0, -0.242, -1.1) neg=(-0.7, -0.342, -1.1)

[BAR]
name=fr_fore_lower posbody=body negbody=fr_spindle pos=(0, -0.242, -0.8) neg=(-0.7, -0.342, -1.1)

//Front-Left steering
[BAR]
name=fl_steering posbody=body negbody=fl_spindle pos=(0, 0.1, -0.95) neg=(0.67, 0, -0.95)

//Front-Right steering
[BAR]
name=fr_steering posbody=body negbody=fr_spindle pos=(0, 0.1, -0.95) neg=(-0.67, 0, -0.95)

[BODY]
name=rl_spindle mass=(10.0) inertia=(0.0275,0.0260,0.0245)
pos=(0.61,0,1.1) ori=(0.0,0.0,0.0)

[BODY]
name=rr_spindle mass=(10.0) inertia=(0.0275,0.0260,0.0245)
pos=(-0.61,0,1.1) ori=(0.0,0.0,0.0)

[JOINT&HINGE]
posbody=rl_wheel negbody=rl_spindle pos=rl_wheel axis=(-1.00,0.0,0.0)

[JOINT&HINGE]
posbody=rr_wheel negbody=rr_spindle pos=rr_wheel axis=(1.00,0.0,0.0)

//Rear-Left
[BAR]
posbody=body negbody=rl_spindle pos=(0, 0.1, 0.8) neg=(0.7, 0, 1.1)

[BAR]
posbody=body negbody=rl_spindle pos=(0, 0.1, 1.1) neg=(0.7, 0, 1.1)

[BAR]
posbody=body negbody=rl_spindle pos=(0, -0.32, 1.1) neg=(0.7, -0.42, 1.1)

[BAR]
posbody=body negbody=rl_spindle pos=(0, -0.32, 0.8) neg=(0.7, -0.42, 1.1)

[BAR]
posbody=body negbody=rl_spindle pos=(0, 0.1, 1.2) neg=(0.7, 0, 1.2)

//Rear-Right
[BAR]
posbody=body negbody=rr_spindle pos=(0, 0.1, 0.8) neg=(-0.7, 0, 1.1)

[BAR]
posbody=body negbody=rr_spindle pos=(0, 0.1, 1.1) neg=(-0.7, 0, 1.1)

[BAR]
posbody=body negbody=rr_spindle pos=(0, -0.32, 1.1) neg=(-0.7, -0.42, 1.1)

[BAR]
posbody=body negbody=rr_spindle pos=(0, -0.32, 0.8) neg=(-0.7, -0.42, 1.1)

[BAR]
posbody=body negbody=rr_spindle pos=(0, 0.1, 1.2) neg=(-0.7, 0, 1.2)
 
Make sure springs are soft enough to allow this displacement when load is cancelled out. Also if the car has a front anti-sway bar, the outer wheel will limit the rebound travel of the inner while cornering.
 
Disable anti-roll bars and see if something changed. There are also pushrod coordinates in hdv file. I have no idea what they are for (coilover substitute?) but maybe their length is also a limiting factor?
 
I changed the pushrod lengths and angles with no change, and disabled anti roll bars and still no change.
 
Try halving the suspension travel in the hdv. I am 110% convinced that rFactor doubles the suspension travel in game. With the long suspension travel you're after you might be hitting some kind of maximum limit.
 
Last edited:
I have had the rebound value for the LF from -0.1 to -.5 it does not matter what I do so far. I have moved the shocks in, out, new angles, longer and shorter A arms. Just about everything I can think of and the LF only travels about an inch in rebound then comes off the track
 
Are the two lines below from your susp file correct? .......... as the left and right side don't match (2nd number in both lines).
I'm gonna guess that your tires lift as a result of the suspension binding-up as it rises.


//Front-Left
[BAR]
name=fl_fore_upper posbody=body negbody=fl_spindle pos=(0, 0.1, -0.8) neg=(0.7, 0, -1.1)

.
.
.
.

//Front-Right
[BAR]
name=fr_fore_upper posbody=body negbody=fr_spindle pos=(0, 0.0, -0.8) neg=(-0.7, 0, -1.1)


Are the tires meant to go straight up and down, rather than gain camber as the suspension compresses??
 
That is a typo, they should be the same. I did catch that while messing with the file some more. Yes there should not be any camber gain, in reality the car I am trying to simulate has a solid beam front axle, and I cannot model that in rfactor. Another issue is getting the roll center high enough with the double wishbone style suspension, but I am trying to work around that.
 
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