My plan is to both groove and sipe my R-4's for better traction. This evening, I did the grooving part. 20 minutes for the first rear tire, 15 minutes for the second (since I had some practice on the first). Here are some pictures of what I did. I'm hoping this improves snow traction some.
When I get a chance I will sipe them on either side of the grooves for even better traction in hard packed snow/ice.
The theory is, the more biting edges the better the snow/ice traction.
It's snowing now, I'll see how they go in the morning!