code:
var FR_wheel_ID;
var FL_wheel_ID;
var RL_wheel_ID;
var RR_wheel_ID;

action FR_tyre
{
my.shadow=on;

phent_settype(my, PH_RIGID, PH_SPHERE);
phent_setgroup(my,2);
phent_setmass(my, 5, PH_SPHERE);
phent_setfriction(my, 70);
phent_setelasticity(my, 50, 10);
phent_setdamping(my, 20, 20 );

FR_wheel_ID=phcon_add(PH_WHEEL,my,p_player);
phcon_setparams1(FR_wheel_ID, my.x, vector(0,0,1),vector(0,1,0));
phcon_setparams2(FR_wheel_ID, vector(35,-35,0),vector(-360,360,0),vector(0.9,0.001,0));
}

action FL_tyre
{
my.shadow=on;
my.pan=180;

phent_settype(my, PH_RIGID, PH_SPHERE);
phent_setgroup(my,2);
phent_setmass(my, 5, PH_SPHERE);
phent_setfriction(my, 70);
phent_setelasticity(my, 50, 10);
phent_setdamping(my, 20, 20 );

FL_wheel_ID=phcon_add(PH_WHEEL,my,p_player);
phcon_setparams1(FL_wheel_ID, my.x, vector(0,0,1),vector(0,1,0));
phcon_setparams2(FL_wheel_ID, vector(35,-35,0),vector(-360,360,0),vector(0.9,0.001,0));
}

action RL_tyre
{
my.shadow=on;
my.pan=180;

phent_settype(my, PH_RIGID, PH_SPHERE);
phent_setgroup(my,2);
phent_setmass(my, 5, PH_SPHERE);
phent_setfriction(my, 70);
phent_setelasticity(my, 50, 10);
phent_setdamping(my, 20, 20 );

RL_wheel_ID=phcon_add(PH_WHEEL,my,p_player);
phcon_setparams1(RL_wheel_ID, my.x, vector(0,0,1),vector(0,1,0));
phcon_setparams2(RL_wheel_ID, vector(0,0,0),vector(-360,360,0),vector(0.9,0.001,0));
}

action RR_tyre
{
my.shadow=on;

phent_settype(my, PH_RIGID, PH_SPHERE);
phent_setgroup(my,2);
phent_setmass(my, 5, PH_SPHERE);
phent_setfriction(my, 70);
phent_setelasticity(my, 50, 10);
phent_setdamping(my, 20, 20 );

RR_wheel_ID=phcon_add(PH_WHEEL,my,p_player);
phcon_setparams1(RR_wheel_ID, my.x, vector(0,0,1),vector(0,1,0));
phcon_setparams2(RR_wheel_ID, vector(0,0,0),vector(-360,360,0),vector(0.9,0.001,0));
}

action car
{
p_player=my;
wait(1);
my.shadow=on;
my.material=mat_metal;

phent_settype(my,PH_RIGID,PH_BOX);
phent_setgroup(my,2);
phent_setmass(my,40,PH_BOX);
phent_setfriction(my,50);
phent_setelasticity(my,50,10);
phent_setdamping(my,20,20);

vec_for_vertex(temp,my,306);
ent_create(mdl_tyre,temp,FR_tyre);

vec_for_vertex(temp,my,36);
ent_create(mdl_tyre,temp,FL_tyre);

vec_for_vertex(temp,my,5);
ent_create(mdl_tyre,temp,RL_tyre);

vec_for_vertex(temp,my,304);
ent_create(mdl_tyre,temp,RR_tyre);
}

why does my car explode when this code runs? first i create the car and the car creates it's tyres then. after reading the manual i came to the conclusion that this would be the way to do it...

and what do the spring damper constants exactly do?