For clarity for others, it's not a case of 770kg x 4.
They need to be rated to support half of the permitted maximum axle weight each. In the case of the T28, that's 1600kg for the front axle and 1550kg for the rear. The greater of the two is 1600kg, so each wheel need a minimum rating of 800kg. I was been generous with my previous comment.
You may think that if you don't carry a full load, then that's OK, but should you be involved in a bump and the vehicle in inspected, that's when the shit will hit the fan.
Ignorance is no excuse. If you are driving a commercial vehicle, you really ought to know the rules.