Multiple timeouts not working?

So I'm still enjoying to work on my fruitmachine, but the way I implement multiple timeouts don't seem to work correctly.
Basically, I've 3 LED's, or fruits - or wheels, and I stop them one by one in order of time. When I spin the wheel, I tell it when to stop spinning. It works by just setting the velocity of the wheel to 0.

Wheel.prototype.spin = function(stopt) // stopt = stoptime
{
  this.vel = (2 + Math.random() * 5) / 40; // give the wheel a velocity
  setTimeout(this.stop, stopt); // tell it when to stop
};

Then you have the stop function

Wheel.prototype.stop = function()
{
  this.vel = 0.0;
};

The spinning happens when the user clicks the button. At that time, spin is called(not Wheel.spin)

function spin()
{
  for (var i = 0; i < N_LEDS;) // loop trough all wheels, spin them
  {
    wheels[i].spin((++i * 500));
  }
  
  setTimeout(function(){
     //... other code. It checks some win conditions and lights and stuff after every wheel stopped.
  }, (N_LEDS + 2.5) * 500);

But, only the last setTimeout seems to be called.
What am I doing wrong?

Here's the full code.