I can’t exactly answer your question, however mine has R4s. R4s are wider than R1. R1s have a deeper tread but I don’t believe the tire is as wide. Just received the machine in spring. I have no experience with this machine in snow. However in far NE corner of Ohio so far it has been great even in muddy conditions. It will make a mess but will go through much mucky stuff that my other (b2650) would struggle with. It’s really impressive. The wider tire in my opinion have quite a bit more traction laterally vs vertically. For garden with a tiller it’s fine…generally use fine, with a heavy use of the loader it’s awesome.