14 CFR § 27.733

Each landing gear wheel must have a tire—

That is a proper fit on the rim of the wheel; and

Of the proper rating.

The maximum static load rating of each tire must equal or exceed the static ground reaction obtained at its wheel, assuming—

The design maximum weight; and

The most unfavorable center of gravity.

Each tire installed on a retractable landing gear system must, at the maximum size of the tire type expected in service, have a clearance to surrounding structure and systems that is adequate to prevent contact between the tire and any part of the structure or systems.