Tires Changing Rear Tire Width

[beenthere]

How much difference is not known, but it would be fact that there is a difference. The slope you are on will account for the difference, as well as the depressions the wheel on the lower side drops into, and the humps/stumps/rocks the wheel on the upper side goes over.
Knowing in the seat of your pants when you are unstable doesn't have a number. Likely one is safe beyond that feeling of "unsafe". It is known as the pucker factor.

Good on the tire swap. You picked up a lot of extra width. Now keep an eye out for brush tearing up the inderside of the tractor. There are some wires and hoses, etc. underside that are vulnerable. Just don't drive into brush and back out. Ugly things can happen.

 

[dfkrug]

Is there much difference in stablility?

My first Kubota was the size of the L3010, and it also arrived with the
AG tires at the narrowest position. I found a great increase in stability
going to the widest setting. If you have AGs and slopes, you should do
this ASAP. Just the rear tires, however, as the tilting front axle does
not benefit from wider wheel spacing (and the OM says not to).