The steel wheels on the Datsun 240z had a Diameter of 14″, and a Bolt Pattern of 4.5″ with 4 studs / lugnuts. These wheels came from the factory and had 2 tire sizes, 165 HR 14 and 175 HR 14. Many Z cars were fitted with Aluminum Wheels at the Dealer or Aftermarket. The wheel and tires got wider over the years for more traction. The spare tire was normal size, until 1977. Nissan switched to “Space Saver” foldable spare tire, designated as C78-14 Tire with a rim size of 5J-14. This came with an air inflation canister. Below is a table of the Tire and Wheel specs of Datsun Z cars from 1970 – 1983.
Some basic tire and wheel definitions.
The first number in the tire size is the width of the tire in millimeters, 175, is a tire with a width of 175mm.
Modern tires have a second number after the width, usually separated with a slash 175/60. This is the Aspect Ratio, This number is the Ratio of the width divided by the height of the tire sidewall. As this number decreases the height of the sidewall decreases also. The HR probably stands for Highway Radial.
Bolt Pattern for a 4 lug rim is designated as 4×4.5″ ( 4x 114.3mm), The 4 is for 4 lug nuts and the linear distance refers to the distance between studs, center to center, that are next to each other.
Rim Offset is the distance the mounting hub is in relation to the center of the wheel. A 15mm positive offset means the mounting hub, where lug nuts contact, is 15mm more towards the outside of rim. Resulting in the center line of rim being moved towards the car 15mm more. Deep dish rims with a negative offset, move the center of rim away from car, causing rims to stick out wider.
Datsun 240z 260z 280z 280ZX Wheel and Tire Specs from FSM by Nissan Motor Corp.
The 1982 – 1983 Datsun 280ZX came in many different models, below is a table of there various models and Wheel and Tire specs. There were too many options to fit in the above table.