Skateboarding Articles
All About Skateboard Wheels & Bearings » Selecting the right skateboard wheels (size & durometer) and bearings
Skateboard Wheels
There are three components to choosing the right wheel.
- Size: wheel height measured in millimeters (mm).
- Width: there is no measured unit - inspect visually.
- Durometer: hardness of the urathane.
Like all skateboard parts, wheels come in all sizes. An interesting attribute to wheels is durometer. This is a measurement of the hardness of the wheel. Wheels are now (thankfully) made of urathane (not clay) that can come in varying hardness. A simple test of durometer is to push your thumbnail into the edge of a wheel. Now try with a different wheel. Notice a difference?
Maybe you didn't notice a difference. Next check the durometer printed on the wheel - see if they are different or not. The durometer value has the letter "a" after it. The larger the number, the harder the wheel.
It's worth mentioning that it is best to have a matching set of wheels on your board. This means all four wheels are matched in size (mm) and durometer (a). Sure some muscle cars have larger wheels on the rear axle, but skateboards don't really benefit from that sort of touch either functionally or visually. It will look dumb and serves no purpose.
Next lets look at wheel sizes and how to choose the right size for your style of riding and the terrain you expect to hit. Today, small wheels are the rage (I don't get it and personally hate small wheels) around 52mm. If you are at a skate park, these will suit you well and do the trick. I prefer a larger wheel closer to 56mm for park riding.
Street Skating
Small wheels can be used for street skating, particularly if you are doing technical tricks. Having the deck lower to the ground - via smaller wheels - can assist with some tricks. Durometers between 95a and 101a are best for street. However, if you want to travel from spot to spot on your board, you may want a larger wheel to absorb cracks in pavement and other small obstacles you may encounter.
Ramp Skating
When riding ramps, I prefer a 58 or 60mm wheel and a somewhat wider wheel. Granted I'm not into doing technical tricks (favored by smaller wheels), but I find a 60mm wheel very good for general purpose riding of a variety of surfaces from street to ramp.
Downhill Skating
If your gig is shooting down a steep hill on a longboard, you'll likely want a nice big, soft wheel. Something that will easily absorb a pebble rather than sending you flying onto your butt. Sizes from 60mm - 65mm and a durometer of 80a - 90a will work best.
Skateboard Bearings
If you bought a set of wheels and mounted them on your trucks without bearings an odd expression should cross your face sometime during assembly. They don't fit very tightly, do they? You need bearings.
in the 70's bearing were loose - when you removed a wheel all the bearings spilled out in your lap. Not a good thing. Fortunately, bearings are now enclosed in a lubricated metal houseing that contains them and keeps a lot more grime and dirt from getting in contact with them.
Additionally, there is a ratings system called ABEC (Annular Bearing Engineers Committee). With a name like that, do you think these guys spend a lot (or any) time skating? Exactly. This is why a little bit of knowledge can be a dangerous thing. The ABEC rating system helps establish dimensions, tolerances, geometry, and noise standards for bearings in an attempt to aid industrial bearing manufacturers and users in the production, comparison and selection of bearings for general applications - nothing specific to skateboarding.
The ABEC rating system includes grades 1,3,5,7, and 9. The higher the ABEC rating, the tighter the tolerances are, making the bearing a more precision part. Sounds good, right? It's not that this system is flawed, but it only measures bearings as hunks of metal, indifferent to many factors that make a bearing good for a skate wheel. Since every bearing is used in a different manner and environment, bearings should be redesigned or customized for special uses, like skateboarding.
All in all, bearings are a fairly generic component to many different industrial enterprises with varying needs in a bearing. Skateboarding is only one of many applications for bearings and probably fairly low in the scheme of bearing manufacturing. For example, components put into a race car are not likely found in your garden-variety Chevy. The point is that skateboarding has different demands on bearings.
High precision and small tolerances are required for bearings to function at very high RPM (Revolutions Per Minute), that must spin at 20,000 to 30,000 RPM. At that speed, an ABEC - 7 or 9 bearing rating may be appropriate. However, a skateboard with 54mm wheels turning 20,000 RPM will be traveling about 127 MPH! Since most skating is done under 30 MPH, the realistic maximum RPM your skate bearings will see is about 4700 RPM and probably 90% of skating occurs under 2000 RPM. So, very high precision is not required at skating speeds.
The dimentions and tolerances controlled by the ABEC standards include the diameters and widths of the raceways, their shapes to some extent and the smoothness of the running surfaces. The system ignores side loading, impact resistance, materials selection and grade, appropriateness of lubrication, ball retainer type, grade of ball, the clearance between the balls and the races, installation requirements, and the need for maintenance and cleaning. All these bearing design requirements are very important to the performance of your skate bearing, even though the ABEC rating says nothing about them.
Skaters know that there can be large differences between bearings that have the identical ABEC rating. Sometimes you'll notice that a bearing with a high ABEC rating performs worse than one of a lower rating. Pretty odd - until you realize ABEC wasn't conjured for the sake of skateboarding.
The bottom line is don't spend more money on a higher ABEC rating just because someone told you bigger is better. That rule mainly applies to pornography - a trade few of us will experience outside of the occaisional DVD rental. The best advice is to try different bearings and see which ones perform best for YOU. Only you will suffer from bad bearings, not the idiot friend who said ABEC 7 rules.
Some information was taken from the Bones Bearings site. What the hell - they're the best!
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