Car Tuning Car Tuning Wheel and Tire Upgrades

Question 1

What does the term 'plus sizing' refer to when upgrading wheels?

Accepted Answer

Increasing wheel diameter while keeping overall tire diameter the same

Answer

Plus sizing means fitting a larger diameter wheel with a lower-profile tire so the overall rolling diameter stays nearly identical to the stock setup.

Question 2

What does 'ET' or 'offset' indicate on a wheel specification?

Accepted Answer

The distance in millimeters from the wheel's centerline to its mounting face

Answer

Offset (ET) is the distance in mm from the wheel's hub mounting surface to its true centerline, affecting how far the wheel sits inboard or outboard.

Question 3

Which tire aspect ratio would give the shortest sidewall height on a 255mm wide tire?

Accepted Answer

255/30

Answer

A lower aspect ratio number means the sidewall height is a smaller percentage of the tread width, so 30-series gives the shortest sidewall.

Question 4

What is the primary risk of running a wheel with excessive positive offset on a front-wheel-drive car?

Accepted Answer

Increased stress on wheel bearings and inner fender rubbing

Answer

Excessive positive offset pushes the wheel inward, stressing bearings with extra leverage and risking contact between the tire and inner fender or suspension components.

Question 5

What is the purpose of hub-centric wheel rings (hub rings)?

Accepted Answer

To fill the gap between the wheel center bore and the vehicle hub for vibration-free fitment

Answer

Hub rings center the wheel precisely on the hub, eliminating vibration caused by a loose fit between aftermarket wheel bores and smaller factory hubs.

Car Tuning Practice Test

Car Tuning Practice Test

Car Tuning Car Tuning Wheel and Tire Upgrades