Technician reported installing an incorrect tire and wheel assembly on an in service aircraft.

Attributes
ACN	1692139
Time
Date	201910
Environment
Light	Night
Aircraft 1
Make Model Name	B777-200
Operating Under FAR Part	Part 121
Flight Phase	Parked
Flight Plan	IFR
Component
Aircraft Component	Main Gear Wheel
Person 1
Function	Technician
Qualification	Maintenance Airframe Maintenance Powerplant
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Maintenance Deviation - Procedural Published Material / Policy

Narrative:

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.

Original NASA ASRS Text

Title: Technician reported installing an incorrect tire and wheel assembly on an in service aircraft.

Narrative: 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.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.