700lbs according to my owners manual. It is called the "Cast Iron Disk option". I have them on my tractor along with fluid in the tires. The fluid in the tires adds about 250lbs per tire. I very seldom need to kick in the front wheel assist, the traction with the weight and R1's is great.
One bad point about this tractor, visibility to the leading edge of the forks is non existent, so I mounted a camera to the loader and put the monitor in front of the steering wheel. This is a real slick setup. Now I can precisely place the forks for pallet work and not pierce anything that should not be.
I like this tractor more every time I climb on it. It does not have all the bells and whistles, but that is why I bought it. It is a great utility tractor that can do some serious work.