B777-200
Maintenance Airframe; Maintenance Powerplant
Time Pressure
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
General Flight Cancelled / Delayed; General Maintenance Action
Aircraft; Procedure
Fellow mechanic was performing an ETOPS check on gate and he found the #9 tire at 20 psi. which required a tire change of #10 as well. I was asked by my lead to go assist in the tire change. I went to the tire rack and grabbed two 777 tires. I thought both were high gross weight tires. We changed the tires before the airplane was sent to the hanger because of a missing jack pad cover.
Technician reported installing an incorrect tire and wheel assembly on an in service aircraft.