Tech Talk: Inline Skate Wheels and Bearings Explained

K2 Alexis Boa Inline Skate

The best part of skating is the speed. Unless it's also the places you get to go while skating. Or maybe it's the exercise. Okay, so there's lots of things to love about skating, but if your gear isn't right, you're going to have a hard time getting to whatever it is you love about skating.

Probably the most important thing to get right is the stuff that gets you rolling - wheels and bearings. While these are the physically smallest parts of a skate, they're without a doubt the most important, because without them your skate is just an uncomfortable shoe.

How to Find Your Ideal Inline Skate Wheel

Wheels are what make an inline skate an inline skate, so don't you think you should pay attention to them? Whether you're picking replacement wheels for a beloved old favorite pair of skates, or shopping for new skates, understanding wheels will help you understand how a skate will perform.

Or to put it another way, they'll help you pick the option that best matches what you want to do. Size Wheel size is one of the easiest things to determine about a skate because oftentimes it's in the name.

The Rollerblade Macroblade 110 3WD Inline Skate? It's on 110s. And the K2 VO2 90 Pro is on 90s. Simple. Even if a skate isn't named for its wheel size, it's almost always written on the side of the wheel, which is good to know when it's time to get replacement wheels.

But does size matter? Absolutely it does! Wheel size affects two factors; how your skate gets and maintains speed, and how your skate handles rough terrain. The most significant impact is on speed, so we'll start there.

Rollerblade Inline Skates in the Mountain

Wheel Size and Speed

Generally speaking, a smaller wheel accelerates faster, simply there is less mass to get rolling so it takes less energy to spin. This is why smaller wheels are ideal for young or inexperienced skaters or anyone who is looking for a quick-handling skate for tight environments. At the other end of the spectrum larger wheels weigh more so they take longer to get up to speed, but that extra mass helps them hold speed better and reach higher top speeds overall.

On top of that, larger wheels will also have a smoothing effect when you have to skate across a rough surface, or even deal with loose debris on your path. Which isn't to say that smaller wheels can't handle difficult terrain, rather than larger wheels allow you to safely and confidently skate at speed without worrying that a textured curb cut is going to throw you off your feet.

What Is The Durometer?

The other important spec to understand with your wheels is the hardness, which is expressed through a durometer rating. The synthetic materials used to make skate wheels are tested for durability and stiffness. This doesn't mean there aren't quality wheels with a low durometer rating, instead think of them as being designed for a specific purpose.

For example, a low durometer wheel like the 80a durometer rated ones on the K2 Raider Boa® Pro Inline Skate offer excellent traction because the wheel is better able to stick to the surface you're skating on. This not only makes it easier to accelerate but also to turn or stop. This is very important, considering the Raider Boa® is a child's skate. Softer wheels also act as a sort of built-in suspension, allowing the wheel to flex on rough surfaces for a smoother ride.

At the other end of the spectrum, high-durometer wheels like the 92 rated ones found on the Rollerblade NJ Pro offer more efficient skating, improved wear resistance, and a more forgiving grip that's perfect for the freestyle skating these skates are built for.

And in between you have something like the K2 Mod 25, who's massive 125mm wheels are rated at 85 on the durometer scale. This is because high-performance skates like this need a balance of grip and high-speed efficiency.

A Bearing’s Impact

It really is surprising how something as small and seemingly simple as a set of bearings can make such a huge difference in how a skate feels. That's because they're actually complex pieces of technology, bringing several precision-engineered components together to help your wheels spin freely.

Rollerblade Bearing Diagram

While there are significant differences in bearings, they all use the same fundamental parts. The ball bearings themselves, or conic or cylindrical bearings for high-end bearing sets, rest between the inner and outer races, which together make up the whole load-bearing structure of the bearing. On one side a retainer helps keep the balls evenly distributed for balanced performance, and on the other side a rubber or plastic shield makes it harder (but not impossible!) for water and debris to get in and damage your bearings.

And of course, there's oil inside your bearings as well, helping all the pieces move freely around each other without unwanted friction that would not only slow you down but also damage your skates or wheels.

But despite this similarity, there is a significant difference in how a bearing will perform, and that difference comes from two main characteristics- Material Races, retainers, and shields are all made from the same basic materials across all bearings. They're mainly steel, with some plastic thrown in especially for shields. So, when we talk about bearing material, we're really talking about the balls themselves.

Steel is the most common, due to the simplicity and efficiency of making them. Most skates use steel bearings, and they are long-lasting and reliable with minimal maintenance.

But for the ultimate in performance, many skaters look to ceramic bearings for an extra edge. Despite the reputation dishes and bowls have for being fragile, ceramic bearings are actually quite strong, and offer a smoother (and therefore faster) ride than their steel counterparts.

Understanding Bearing Ratings

Replacing Wheels and Bearings on Inline Skates

This part can get confusing, because unlike many other sports or even other parts of inline skating, there is no universally agreed-upon rating system for bearings. What is agreed upon is what the ratings means: a higher-rated bearing is built to a more precise standard, meaning they will roll smoother and last longer, improving your efficiency while skating.

Bearings from the company known as TWINCAM use their proprietary ILQ (InLine Qualified) rating system. ILQ uses a simple number scale (9 being the highest) to indicate the level of precision each bearing is built with, giving you the ability to compare ILQ-rated bearings against one another.

But the most common rating system is ABEC. Standing for "Annular Bearing Engineering Committee", ABEC is a standard maintained by the American Bearing Manufacturers Association, an industry group that includes inline skate. So, while the ABEC system isn't inline skate-specific, it is a universal standard. This means regardless of the brand you can compare ABEC 5 with ABEC 7 bearings, and know with confidence that the ABEC 7 bearings are more precise, and therefore faster and smoother.

Of course, this is only part of the consideration that goes into picking replacement wheels for your skates. And if you're shopping for completely new skates, there's a whole lot more we can talk about. But don't worry, Peter Glenn will always be here to help you find the answers to the gear questions you're asking.