Is It Right The Bigger The Modified Wheel, The Better?

1, Wheel size has a matching upper limit
There are two types of wheel hub enlargement: simply increasing the diameter of the wheel hub and replacing the flat tire at the same time. The original factory wheel set has a set of balance standards, and exceeding the reasonable range will comprehensively degrade the vehicle's performance.
Original factory standard matching logic
Wheel hub diameter ↑ → tire flatness ratio ↓ (thinning of tire wall), ensuring that the outer diameter of the tire remains almost unchanged, which is a legal and non damaging upgrade for the car;
If the wheel hub is simply enlarged without reducing the tire wall, the outer diameter of the tire will increase, which will directly lead to a series of problems.

2, The disadvantage of blindly increasing the size of the wheel

1)The handling and driving experience have significantly decreased
The tire wall becomes thinner, the buffering stroke is extremely small, and there is severe shaking when passing speed bumps and potholes, without any shock absorption;
The tire sidewall is weak, and bumps and potholes are prone to bulges and blowouts, resulting in extremely high maintenance costs;
The grip area increases, low-speed turning becomes heavier, and it is difficult to turn in place.
2) Acceleration and fuel consumption decrease
The weight of the large wheel hub and wide tire is greater (especially for poor quality cast large wheel hubs), and the quality under the spring has skyrocketed:
Slow starting acceleration and sluggish power;
Rolling resistance has increased, and urban fuel consumption has generally increased by 0.5-2L/100km;
The braking distance increases, the braking burden increases, and the brake pads wear out faster.
3) Damage to the chassis and transmission system
Excessive outer diameter of tire:
When turning or passing through potholes, the tire rubs against the wheel arch and lining;
Changing the speedometer reading, the mileage and speed display are inaccurate;
Increasing the load on the half shaft, bearings, and suspension can lead to abnormal noise and accelerated aging;
Extreme large size will wear down the rubber sleeves of the shock absorber tower top and lower swing arm.
4) Annual inspection and road compliance issues
In most regions, annual inspections require tire outer diameter errors to be within ± 3%, and wheel hub sizes exceeding the original factory specifications cannot pass the annual inspection normally. There is also a risk of punishment if inspected on the road.
5) Safety hazards
Large flat tires have poor heat dissipation and are more prone to tire blowouts at high temperatures and speeds; The large wheel hub has a high rotational inertia, making it more difficult to control the vehicle in the event of a sudden tire blowout.
3, What size is suitable? Security upgrade standards
Conservative and prudent plan (preferred for household commuting)
Wheel hub diameter+1 inch, synchronously reducing tire flatness ratio to ensure almost constant outer diameter.
Example: Original factory 17 inch → upgraded 18 inch, daily comfort, minimal fuel consumption changes, and basically no pressure during annual inspections.
Advanced modification (posture/mild performance)
Wheel hub diameter+2 inches, must be paired with low flat tires, while adjusting suspension suspension and lining, suitable for frequent running on flat roads, not recommended for home commuting.
Not recommended
+3 inch and above oversized wheels, only suitable for static display in exhibition halls, completely impractical for daily commuting.
4, Addendum: Two key points that are more important than size

Unsprung mass
Under the same size, lightweight forged wheels are better than heavy cast wheels, even if the size is slightly larger, it has less burden on power and suspension; Poor quality large cast wheels are the worst choice.
ET value, hole spacing, center circle
No matter how attractive the size is, if the ET is not correct, it will rub against the brakes and wheel arches, and if the center hole is not matched, it will shake at high speed. These parameters have a greater impact on safety than just size alone.