Consider a man riding a bicycle on a horizontal road around a circle.

The situation is as simple as one imagine.

If we need to find the angle which the inclined bicycle makes with the horizontal ground, we consider the torque.

But why can't we take the point of contact of the bicycle and the ground into account?

Error yields showing that there's always a net torque by the weight to rotate the bicycle.

Anyone helps? please

Can you restate the question? I don't understand what the difficulty is. The torque is measured with respect to the contact point, since that's the point of rotation.