Electric Skateboard Basics: Bearings & Bolts
Bearings and bolts may not be as big as other components of electric skateboards, but they are essential parts that can not be neglected. Having certain comprehension of bearings and bolts is definitely helpful for you to understand how your skateboard function and how to maintain your board if there is something wrong.
When it comes to selecting skateboard bearings, choosing the best can be difficult. You may know a lot of things through marketing or shoptalk, but that can be hype or hearsay. There are so many different features that going into bearings that make one better than another. There are ABEC ratings, steel and ceramic bearings, metal shields, rubber seals, nylon retainers…All these make the whole process of choosing the best bearing really difficult! Even if you’ve got the best bearings, you have to know how to maintain them to keep them clean and continue to roll fast. So to start with, throw yourself some basic knowledge about bearings.
Skateboard bearings may be small, but they are incredibly complex. When you first see your electric skateboard, you will probably not notice the bearings at all. It isn't until you need to do maintenance on your bearings that you will have to split them open and learn about what's inside. Skateboard bearings are comprised of seven smaller parts:
1.C-ring: a C-ring holds a removable metal shield in place on the outer race.
2.Metal Shield: a little plastic part on top of the bearings that you can easily take off. It prevents dirt from getting into the ball bearings.
3.Outer race: the round metal exterior that all of the other parts fit into.
4.Inner race: the smaller metal ring that fits within the outer ring. When you slide your bearing/wheel setup onto the axles, the inner ring is what the axles fit through.
5.Steel balls: a set of 6 or 7 steel or ceramic balls that rest in the ball retainer. The balls will be traveling in between both of the inner ring and the outer ring. In order to not have the balls hit into each other, they are spaced by a retainer.
6.Ball retainer: the ball retainer holds the individual ball bearings in place, while still allowing the casing to spin around them.
7.Rubber seal: A soft rubber ring on the outside of the bearing that assists in shielding the bearing interior against dirt and debris.
Notes: The bearings of electric skateboard are all Size 608 bearing with dimensions of 22mm for outer diameter, 8mm for inner diameter, and 7mm for width. There are 8 bearings in total for a skateboard and 2 precision bearings for each wheel.
Bearings have different precision and durability. Most bearings are measured by the ABEC grade. ABEC was started by the American Bearing Manufacturer’s Association to set standards for dimensions. The ABEC rating system includes ABEC 1, ABEC 3, ABEC 5, ABEC 7 and ABEC 9. The higher the ABEC number, the more accurate the precise the bearing. But ABEC only rates tolerances, so it doesn’t rate the bearings from worst to best, it’s more of a grade or class. Well, if ABEC only measures and rates tolerances, can an ABEC 3 be better than ABEC 7? The answer is yes. ABEC does not rate speed, durability, ball sphericity, torsional loads, axial loads, surface finishes, torque, lubricants.
The ABEC ratings was initially created to shoot industrial bearings that are turning way faster than skateboard wheels. While skateboarding you apply forces in a very different way than industrial bearings. The ABEC rating does not apply to skateboarding because of the tolerances set in the ABEC scale. But that’s not to say the tolerances are not important to skateboarding. And you will notice the very specialist brands of bearings don’t even mention ABEC ratings anymore. They may have created their own skate-specific rating. So in general, the ABEC ratings will not really give you a clear indication of bearing quality.
Roughly there are two main materials that bearings can be made out of. The first one and the most classic will be steel. Most skateboard bearings are made of steel. Stainless steel bearings will not rust. With steel bearings, the overall quality of the steel, the sealing, and the interior ball bearings varies from brand to brand. You can really feel the difference when you come to a sudden stop on your board. There are also a lot of pricey bearings that will be made out ceramic. Ceramic doesn’t rust, it can withstand higher temperature. It’s lighter than steel and harder than some steel grades. Ceramic is a material that is supposed to be not stretchable. Therefore, ceramic bearings are supposed to last very long if you treat them good.
So is there an advantage to having ceramic balls over steel balls? Well, you should first know that ceramic bearings are actually hybrid bearings, meaning that the balls are ceramic, but the inner and outer races are still steel. So ceramic bearings can rust. Ceramic balls can surely withstand higher temperatures, but steel balls never get hot enough to deform or affect performance. Yes, ceramic balls are lighter than steel balls, but the weight difference is so minimal that you won’t even notice. Actually ceramic material is more brittle than steel, which means it can crack, chip and break. Ceramic balls are harder than some steel balls, but not all. In a word, ceramic balls don’t really have an advantage over steel, if any.
-Care & Cleaning
As soon as bearings are taken out of their package and put into a skateboard wheel, there are pretty much instantly susceptible to corrosion, because they are exposed to everything. So at some point in time you have to clean your bearings. Before we get into that, there is one thing you need to know is that when a bearing is not spinning very well or it’s not spinning at all, it’s best to just go ahead and replace it because no matter how much cleaning you do or how much lubricant you put in there, it won’t work to its intended optimum performance. So it’s best to just throw it away. Another thing is that when you spin your bearing and you hear a hissing sound, that does not mean that your bearings are broken. That means your bearings are dry and they will fall apart really soon because there is no lubricant in them.
Lubricants can escape out of the bearing which can ruin the bearings performance. Contaminants like dirt and moisture can find their way into a bearing because the inner bore of the inner race does not fit tight on the axle. And also very minimal amounts of lubricants or contaminants can enter or escape between the inner race and the cover. The best way to clean bearings is with a bearing cleaning kit. What you would do is to take off the shields, then put bearings in bearing cleaning kit, fill the kit up to a quarter or a third of the way with cleaner and shake it up. Take them out when you took the dirt out. And now you can oil them. Let them dry completely and put the shield back before you place them. For cleaning your bearings, stay away from extremely dangerous chemicals like acetone, mineral spirits, gasoline. Cleaners containing orange oil (an organic compound called terpene) are recommended.
Lubricating skateboard bearings can be very important, as it could enhance their performance and longevity and keeps your skateboard wheels performing in top shape. Choosing the right lubricant cannot be easy. Do remember the tips mentioned here. The type of lubricants you want to stay away from are the thick heavy ones like motor oil or grease like white lithium grease and even household oils. Those are made for big heavy moving parts and will actually slow down a bearing because they are thick. Try to find those lubricants that are made for small moving parts that need to move really fast on a regular basis. Sewing machine oil and electronic oil are fine choice. Some electronic oil comes with a hypodermic needle and that’s really handy while you’re out skateboarding. You don’t have to take off your wheel. You can just get right in between the shield and the inner race and put in a few drops of oil.
Nuts and bolts can be referred to as hardware. Hardware comes in 8 bolts and 8 nuts to hold the skateboard truck together with the deck. There are hexagonal screws and cross-head screws of different lengths and colors to allow the skater to mark the front and back of the skateboard. Skateboard bolts and nuts are specifically made to fit perfectly in the holes in your deck as well as into your trucks. When browsing through the skate shop you’ll find both countersunk and raised head bolts. For skateboarding, countersunk bolts are needed to form a smooth surface when set in the deck, so that you can stand more comfortably on the board. Raised head bolts are only suited for drop-through longboards.
Also we have self-locking nuts, which largely prevent bearings from loosening due to strong vibrations or tension. During your skating, do remember to check your nuts to make sure all nuts are still tight. Sometimes bolts may be stripped. This does happen but it’s not super common. To take off the bolts quickly and replace them with new ones, you need to go for the right screwdriver. Damage to a screw head can be caused by using the wrong size screwdriver for a different size screw head. Bolts and nuts are even smaller than bearings, but all these components are of great significance to the whole skateboard.