Interesting, how some of these older threads get bumped back to the top for reasons I can't spot...
The problem at hand isn't with that truck, or its brakes, or its tires. The problem is with the tiles - they were never laid correctly in the first place, or they would not have begin breaking.
Tiles for an application like this need to be (1) laid over a thick concrete floor with a very uniform, level top surface specially finished for floor tiles. (2) heavy red clay body for compression resistance. (3) bedded fully in a full-buttered coat of thinset mortar with absolutely no air gaps anywhere, pressed firmly into the mortar bed. (4) grouted well. If any of those four isn't true, those tiles will crack. If all four are true, you can nearly drive a battle tank across that floor without breaking tiles.
But... I doubt very much that the company will have much interest in relaying that floor, am I right? Such is life. In the long run, it'd save them more money to do the job right - now - than have to deal with this issue appearing again and again. It WILL reappear. Next time it may be a little lightweight vehicle that cracks a tile. It MAY be a heavy person - 830kgs over three tires is less than 300kgs per tire, and a very heavy man tipping up on his toes or his heels can exert more pointed floor pressure than that truck can. Pretty close - your hard tires' footprints are very narrow.
What can you do to improve things? Your only option, really, since you're forbidden to use wood (I'd recommend wide planks instead of plywood) will be to make those tires as fat and soft and pillowy as you can, mostly fat. You're going to want to make the tires' footprints as large as possible, so the vehicle's weight is spread over as wide an area as possible. That implies soft tires to make each footprint large & square, and that softness will also take some of the abruptness out of braking & accelerating. Can you at least double the rear tires? It'll make steering worse, since dragging two tires around in a tight circle presents a lot of extra shear stress, but in straight runs it'll spread out that load.
Larger DIAMETER tires would actually help as much as FATTER tires would... but it doesn't look like there's any room on that truck for larger diameters.