As someone that just went from a utility tractor (NH WM55) with R1s to a compact (Kubota L6060HSTC) with R4s in the past two months I can tell you my opinion thus far.
I haven’t picked up any super heavy loads with my R4s yet other than buckets of rain soaked mud earlier this week, but I have not noticed any bulging like I would with the R1 tires I had on my last tractor. When lifting to loader max on my last tractor, which was about 1400# with my clamp on forks, the front tires would bulge bad. I filled them to max air to be able to lift heavy loads. I had the same issue in my tractor before that as it had R1s as well but was smaller with much less lift. I would say likely if you got better R1s they might not bulge as bad.
I can’t speak to stability much because I haven’t had my R4s on the hillside yet due to the mud and snow this year. But the stiffer tire feels more stable on the inclines I have had it on. It doesn’t bounce as much on uneven ground. It also rides much smoother on hard ground like the road and my driveway.
Snow traction the R4s have been much better than I would have guessed. I have yet to have an issue on my driveway clearing snow and it’s rather steep. My R1s I got to where I did not trust them on my driveway because sometimes it would lose traction on icy spots.
Mud traction on the R4 tires is pathetic compared to the R1s. It’s like nascar tire spinning on ice. As others mentioned the bucket is a necessity to move the tractor when finding yourself in that condition. The R1 tires had their issues with mud too, I’ve gotten in positions where I could not push into dirt/mud to lift it or unable to pull the box blade forward. However, they would always go without help in the thickest mud. The R4 tires don’t steer well in the mud, and the R1 tires did not usually have that issue.
Damage to my yard during soft winter conditions of the thaw season still happens with the R4 tires. The ruts are not quite as deep and the water does not pool in the ruts allowing the water to drain better from them. Damage to my gravel driveway is far less with the R4 tires versus my previous R1 tires especially when turning in a tight radius.
I got the R4 tires based on my usage and damage to my yard and driveway. I hope I don’t regret it when mowing on the hillside.
I never had issues with punctures on my last R1s. We had a house built and they were very careless with nails along with other materials. Plus I did a lot of brush clearing in wooded areas and took out a couple barb wire fence lines. Now my smaller tractor before I did manage to get a hole in one of the fronts and I discovered it already had a tube. I just put another one in it.
If you want maximum traction on dirt and mud no doubt get the R1 tires, especially for ground moving implements. If you’re lifting and doing more construction oriented things, or lots of snow removal, then R4s.
Also, I have always had my rear tires loaded. My last tractor also had the fronts loaded which I think helped for turning.
Matt
Ps: This is what I was into earlier this week preparing for the flooding we are getting now. I used the loader to make that big pile after I reduced the elevation to promote drainage in this area until I can fix the mess come dry weather. The mud was about 6-8” deep, just below the top of my mud boots in some places.
