When the centripetal force is greater than the frictional force, skidding occurs.
If μ is the coefficient of friction between the road and tire. then the limiting friction (frictional force) is f = μR where normal reaction R = mg
f = μ (mg)
Thus for skidding,
Centripetal force > Frictional force
mv2/r > μ (mg)
v2/rg > μ
but, v2/rg = tan θ
so, tan θ > μ
When the tangent of the angle of banking is greater than the coefficient of friction, skidding occurs.