I bought a M7040 new in 2012 with R4 tires. I never gave much thought to the tire brand Kubota would put on a new machine.
The tires are made in Czechoslovakia with the brand name Mitas.
After a couple of years, I decided to invest in TRYGG studded chains for the rear. The chains were advertised by TRYGG as needing no fitting. Cost $1,500.
When I started to install them they were too long. It took me a year with help from TRYGG, which I commend them for, to get them fixed.
In the mean time the chain on the right side came off, hooked unto the step into the cab and bent the shxt out of it,
The Tire and Rim Association publishes tires and wheel dimensional standards which all manufacturers follow.
My Mitas tires were 3" in diameter smaller than the Tire and Rim spec and that is why the chains did not fit.
Trygg convinced their distributor in Quebec Canada (Chaineselect.ca) to modify the chains to fit my undersized tires at no cost to me. I had to ship the chains to Quebec but here a friend in the trucking world helped out and the shipping was free.
I wrote to Kubota Canada but was ignored. Why a company with a great reputation would first put such tires on a new machine and second ignore the owner who is complaining. It makes no business sense that I can see.
From Tire and Rim Association:
Standard 16,9 x 28 ***8211; R4 tire is approximately 55.52 inches high.
I placed large carpenter***8217;s level (horizontal yellow tool) on top of the tire lug and measured to the ground.
52.625***8221;
Almost 3 " smaller in diameter which, using old math formulas: C= 2xpi x radius: Circumference, or length of tire chain would be
For Mitas tire: 165.25
For tire meeting spec 174.42" which is the one I received from TRYGG
In simple terms my chains were 9" too long.
My main point in all of this is to make certain your tires are made to the international spec size before ordering chains.
Dave M7040