@toffeez
The Rejected Take-Off test is performed at MDTOW. For example, the A380-800 RTO was performed at a weight of 575 tons, even though the highest MTOW (WV002) at the time was 569t. Airbus has subsequently issued WV006 (573t) and WV008 (575t). If Airbus wishes to offer a higher MTOW than 575t, they will need to add the four additional main wheel braking units and perform a new RTO test.
Tire size and loading determines how much weight the undercarriage can support. Tire size and loading also affect pavement loading which determines how much weight an airport facility (runway, taxiway, ramp, bridge, gate, etc.) can support. When the 777-300ER first started operations at Paris-Orly, the pavement loading was so high that it damaged parts of the airport and additional structural reinforcement was necessary.