Bearings are the mechanical parts that sit between the axle of the truck and the core of a wheel, facilitating spin. They are an incredibly common part in most mechanical systems, and skate bearings are nothing special compared to the more fancy bearings available in the world for other uses.
There is very little to complicate about bearings. Virtually every bearing performs exactly the same, so it’s best to buy a set that is convenient and cheap.
Bearing Spacers
The only true quality-of-life innovation in the bearing world is the built-in spacer.
If you open a pack of Bones Bearings Reds bearings, you’ll notice 8 bearings and 4 spacers. The spacer is the small metal tube that sits between two bearings inside the wheel core.
This spacer keeps the inner races aligned so that when you fully tighten your axle nut, you do not side-load the bearings. Without a spacer, tightening the nut can pinch the inner races toward each other, increasing friction and slowing your roll.
About ten years ago, Zealous Bearings popularized bearings with an extended inner race that functions as a built-in spacer. This eliminated the need for separate metal spacers. It is a genuine convenience improvement. You install the bearings, tighten the axle nut fully, and the spacing is usually automatically correct.
There is some manufacturing variance in the span between the two bearing seats inside a wheel core. This dimension is not perfectly standardized across all wheel manufacturers.
There is also manufacturing variance in the width of the extended inner race on built-in spacer bearings. Not all “integrated spacer” bearings are dimensionally identical.
Because of this, some bearing brands do not fit optimally into certain wheel cores. For example:
- Loaded Boards Jehunion V2 bearings are too short for many Powell-Peralta wheel cores.
- Zealous Green bearings tend to fit Powell-Peralta cores properly.
If the extended inner race is too short relative to the wheel’s bearing seat span, tightening the axle nut can still introduce side-load and friction. If it is too long, you may not be able to fully seat the bearings into the core. Generally though, you’ll be alright.
Whether you choose built-in spacer bearings or traditional bearings with separate spacers, you should never spend more than $30 USD on a set of skateboard bearings.
The Least-Effort, Highest-Value Bearing Method
- Buy two sets of bearings at first.
- If you skate in the wet, spin them until they’re dry when you get home.
- As your bearings get crunchy or seize, replace one bearing at a time from your spare set.
Using this method, I buy a new set of bearings once every two years or so.
Bearing Marketing is a Scam
Most bearing marketing is a total sham. Bearings are a high-margin item, so companies traditionally expend much effort convincing consumers to buy their bearings. The list is long:
- The Scam of the Free-Spin Test
- The Scam of the ABEC Rating
- The Scam of the Ceramic Bearing
- The Scam of the Naked Bearing
- The Scam of Monthly Bearing Maintenance
The Scam of the Free-Spin Test
For as long as skateboarding has existed, people have performed the same misguided ritual: mount a wheel on a bearing, give it a flick, and time the spin to “measure speed” or predict how long a setup will roll before the next push.
This test is a sham.
Skate bearings do not operate in an unloaded state. They operate under radial and axial load, subjected to rider weight, pavement vibration, and dynamic side loads while carving. A free-spin test isolates the bearing from the very forces that define its real operating conditions.
A long free-spin time is not evidence of real-world speed. It is evidence of low unloaded drag, which is largely irrelevant once the system is under load.
The Scam of the ABEC Rating
The Annular Bearing Engineering Committee (ABEC) scale is an industry standard that defines machining tolerances for ball bearings. It specifies how precisely components like the inner race, outer race, and bore are manufactured. It does not measure material quality, lubrication, seal design, durability, or impact resistance.
ABEC classes were developed for high-speed industrial applications such as electric motors and machine tools. These environments bear little resemblance to skateboarding.
Skateboard bearings experience:
- Repeated impact loading
- Significant side loading during carving and sliding
- Contamination from dust and water
- Relatively low rotational speeds
Wheel RPM in skating is modest. At these speeds, the incremental geometric precision difference between ABEC 3, 5, 7, or 9 produces no meaningful performance gain. The tolerance improvement simply does not translate into perceptible speed or roll distance under real-world riding conditions.
What matters more functionally:
- Surface finish of the raceways
- Steel quality and heat treatment
- Lubricant viscosity and consistency
- Seal type and contact pressure
- Proper spacers and axle compression
ABEC is a dimensional tolerance specification. It is not a performance rating.
Further, most commercially available skate bearings are manufactured in the same handful of large bearing factories and then private-labeled for different brands. The differentiation is typically in seals, lubricant, branding, and quality control, not in some proprietary geometry defined by an ABEC number.
The Scam of the Ceramic Bearing
Contrary to popular belief, ceramic bearings are not waterproof, and waterproofing is not why ceramic ball bearings were developed in the first place.
Ceramic-balled bearings, more precisely called hybrid ceramic bearings, exist primarily for heat and friction tolerance. Ceramic balls, commonly silicon nitride, exhibit lower thermal expansion than steel and can tolerate high temperatures without deforming. In industrial contexts such as high-speed spindles or aerospace applications, this stability under heat is valuable.
Skateboarding does not resemble those environments, as friction and heat buildup is not the limiting factor in skate bearing performance except for top speed pursuits in excess of 100 km/h.
Commercially available “ceramic bearings,” such as Bones Swiss Ceramics, are hybrid bearings. They use ceramic balls but still rely on steel inner and outer races.
If those steel races corrode, pit, or rust, the bearing will degrade regardless of what the balls are made from. The rolling interface is still steel-on-ceramic contact inside steel raceways. Rusted races mean rough rotation. Ceramic balls do not prevent that.
Commercially available “ceramic bearings” such as Bones Swiss Ceramics are still made with steel races. This means that if the inside of the steel races rust, the bearing stops rolling nicely anyway.
There are fully ceramic bearings where the races, balls, and cages are all ceramic. These are used in highly specialized industrial environments. They are:
- Extremely hard
- Extremely corrosion resistant
- Also brittle relative to steel
Brittleness makes them poorly suited for repeated impact loading, which is fundamental to skateboarding. They are not engineered or packaged for skateboard use because the failure mode under shock would be catastrophic.
The Scam of the Naked Bearing
Recently, some brands such as Bronson Speed Co. have marketed bearings that run without shields or seals. The implication is reduced drag, freer spin, and less resistance.
This framing ignores the primary function of a shield. Shields exist to prevent contamination.
Skateboarding is an abrasive environment. Pavement dust, sand, metal shavings, moisture, and fine grit are constantly present. Without a seal, debris enters the bearing immediately.
Once contamination enters the raceway, several things occur:
- Hard particles indent the steel races
- Micro-scratches form along the rolling path
- Surface finish degrades
- Lubricant becomes contaminated and abrasive
At that point, the bearing is no longer rolling on a smooth, hardened surface. It is rolling across damage it created itself. Performance declines quickly and permanently.
Removing the shield may reduce negligible seal drag in a sterile, laboratory scenario. In real-world riding, the increase in contamination overwhelms any marginal reduction in resistance.
The Scam of Monthly Bearing Maintenance
Some skaters take apart their bearings, clean them out with isopropyl alcohol, and re-grease them once a season or so to keep them reasonably upkept. This sort of cleaning does make bearings last longer.
A good, reasonably effective way of cleaning bearings is as follows:
- Insert the tip of a knife (I like a craft type knife) in between the inner race of the bearing and the shield and pry up gently. The shield should pop off with ease.
- Put your naked bearings in a wide-mouth water bottle or mason jar and cover them with 97%+ isopropyl alcohol.
- Seal the container and shake them for a good minute.
- Take them out and dry them completely. I like using canned air or an air compressor to blow them out.
- Use a grease of your choice to re-lubricate them (remember, WD-40 is not a lubricant). I like gun grease or white lithium grease (the kind made for garage door springs).
- Pop the shields back on and go skate!
You can do this too much. The most lasting legacy of longboarding will be the schitzo-paranoia of bearing cleanliness. Some folks apparently clean their bearings once a week. That is psychotic. Don’t do that.