Skateboard bearingssize

I took it to my local mechanic because of a humming in the passenger side tire when cruising. My mechanic tells me the ball bearing is starting to become defective and suggest replacing both front ball bearings which will be $500+.

• Faster acceleration and top speed. • More precision and grip. • Insane durability. • Removable protection shields with own internal rails, which completely blocks the entry of dirt without generating any friction. • Thin nylon cage with fiberglass, made to generate the least possible friction. • All parts are produced exclusively by Minebeamitsumi. • Developed especially for Cuei Wheels.

I have a 2015 Mazda 3 that has 33,000 miles on it (bought it CPO from the dealer at 28,000 miles, only driven 5k miles personally).

Skateboard Bearingsand wheels

Plus he suggests changing the wheel's brake pad and rotor because of creeping rust, which would be $100 in parts, but labor is free because the brake/rotor will have to be removed anyway.

The new Nano Tech Skate Bearings, developed by Cuei Wheels in partnership with Minebeamitsumi, one of the largest bearing manufactures and which holds the world record (Guinness) for the smallest and most precise bearing in the world, just came to innovate and increase the quality standard of Skateboard bearings. Produced on ultra-precise machines, these bearings have a meticulous polishing process, which reaches the Nano (RA) level of smoothness on the surface of the balls and race tracks, which in itself already causes this bearing to require less torque to spin. To make this bearing even more special, we had the opportunity to try out variants such as tolerances, depth and angulation of the racetracks, different material alloys and innovative designs. What makes this bearing completely developed for skateboarding. To start we will have two designs, the Classic 608S which is the most used model in the industry today and the Race Model 1980S which obtained the highest results in laboratory and practical tests. This model has more weight on the external part of the bearings, which makes their inertia absurd, in addition to a smaller diameter on the rails which makes traveling a shorter distance for each turn of the wheels. The result is a faster bearing with a faster response.

Is it normal to have to replace both front ball bearings like this and not just the bearing on that wheel? He said it can be bad down the line if both sides' bearings aren't the same in terms of resistance. And mentioned that the rusty rottor will cause issues down the line, but I've only driven the car 5k, why would the rotor be so rusted it would need to be changed?