I have just had installed 4 winter snow tires and new BMW alloy wheels. I notice that the wheel weights are installed on the outside of the wheel where they can be seen. My summer BMW wheels are weighted on the inside and therefore cannot be seen. Is there a reason why the winter wheels have the weights on the inside? Thanks fellas.

It's just a coincidence, depends on the tires really.

I would say the company that mounted the tires just didn't put the weights on the back side. There is no difference in the function. They just look better hidden.