Why is there rust inside the wheels of a new car?

[VanGriffin]

It is normal for the steel rims inside new car tires to have surface rust, as they are made of cast iron, and this generally does not affect their normal use. Many car models use aluminum alloy to make the wheel hubs. The advantage of aluminum alloy is that it is sturdy and durable, but the downside is that it is susceptible to acid. Aluminum is easily oxidized when exposed to acid, and if placed in a strong acidic environment, aluminum alloy wheel hubs can indeed corrode. Specific details are as follows: 1. Rust condition: If the rust on the brake disc is minimal, no special treatment is needed, as the slight rust will be removed during braking while driving. If the rust is more severe, it may cause vibrations or shaking during braking, such as brake pad vibration, steering wheel vibration or shaking, or body vibration. 2. Timely maintenance: Severe rust is difficult to remove through braking, and even if the rust is removed, it may cause brake vibration due to uneven thickness of the brake disc. Therefore, it is necessary to perform maintenance on the brake disc every two months to prevent the rust from becoming too severe.

[OFinn]

When I bought my new car, I also noticed rust inside the wheels, which is quite common and nothing to worry about. The rust inside new car wheels is mainly caused by the oxidation of brake discs or related metal parts exposed to the air. During transportation and storage, cars may be parked in humid environments without anti-corrosion coatings, making iron parts prone to rust. This is not a quality issue; in fact, it indicates that the brake discs are made of cast iron, which is sturdy and durable. Once you drive and use the brakes a few times, the friction will wear off the rust. I've tried it with several new cars, and it's always been fine. If the rust is severe or there is reddish-brown rust water leaking, it might be due to improper storage, but the probability is very low. New cars undergo testing before leaving the factory, and rust does not affect braking performance. It's recommended to drive more or consult the dealer for peace of mind. In short, don’t worry too much about such minor issues.

[Rowan]

I've noticed that rust on new car wheels is quite common, mainly because the brake system design omits anti-rust coatings to save costs and improve performance. Iron components oxidize and rust when exposed to moisture in the air, such as during transportation from the factory to the dealership. This isn't a defect—light rust on brake rotors doesn't affect safety and naturally wears off after driving. From my experience, most new cars exhibit this, so no need to worry. If rust spreads significantly or worsens persistently, it might indicate overly humid parking conditions, but manufacturers have accounted for this. In short, it's normal—don't rush to repair or replace parts.

[DeVivienne]

Rust inside the wheels? I've seen many new cars like this, especially during the rainy season. The reason is simple: the brake discs aren't coated with protective paint, so they easily oxidize and rust when exposed to air. It's more common for new cars to get damp during storage. But the rust is very shallow and will wear off as soon as you start driving. Personally, I think it's completely normal and doesn't affect driving.