Inline Skate Wheels – A Guide To Wheel Sizes And Wheel Hardness

So you need a set of inline wheels. Maybe you’ve worn yours out, maybe your skates have arrived and there’s no wheels! But which do you get? Go to any skating website and there’s hundreds of the things all different colours and sizes with weird numbers by them. What do you do? This short guide will suddenly make you a pretend-expert on skating wheels.

So, what skate wheels do you need? Rollerblade wheels vary on size (mm) and hardness (A rating). Aggressive skate wheels are small and very hard (42 – 72mm, 88 / 90A), recreational and fitness wheels are large and medium hardness (70mm – 90mm, 78 – 84A), speed skates are very large and medium hardness (90 – 100mm, 78 – 85A), and hockey skates are medium and relatively soft (72 – 80mm, 72 – 74 A).

That’s a pretty good summary actually, but a little bit of explanation is probably need. Let’s work out what those numbers mean for you…

What Wheels Do I Get For Inline Skates?

Straight off the bat, if you’re looking to simply replace your wheels with the same ones look on the wheels and see those two numbers? You want to match those two numbers. If they’ve rubbed off the wheels, the maximum size your skate frame takes should be written on the frame.

There are two main things you have to know about wheels before you choose them. And the great news is, the two features of wheels you need to know about are written right on the side of the wheel. If you’ve got a skate wheel handy, look along the side and you will see two numbers. These numbers refer to the two important features:

The size of the wheel – this is the number followed by MM (millimetres)
The “hardness of the wheel – this is the number with an A next to it

I will take these each in turn to explain why they matter to your skating, and then afterwards go into the combination of hardness and size you need for different types of skates, and different skating activities. By that point, you should know all you need to have a go at buying some new wheels. The other two points I’ll quickly mention now: the hub size (but they’re pretty much all the same nowadays), the bearings (but you’ll have these anyway and will need new wheels quicker than new bearings), and the material quality of the wheel (this is basically how much money you spend, or how great the company is). But really you just need to know the size and the hardness to make the right choice.

The Size Of The Wheel

Inline skate wheels range from 50mm to 110mm in diameter. So this is 5cm (pretty tiny) all the way up to 110mm. As you can imagine having different size wheels feels a lot different on your feet. The really big ones will have you quite high off the ground and this means you’ll have less stability. Imagine really tiny wheels versus standing on a high pole and you’ll get the idea. Your ankles have further to move and it’s a bit harder to balance.

The reason there are so many different size wheels – 55, 60, 70, 80, 90, 100, 110 (and the ones in between with 5s on the end) – is because as you change the size of the wheels they become suited for different types of skating.

The biggest difference is speed. Big wheels are faster. Now, other features like the bearings you have on your skates will also impact this, but it’s basically true all the time – the bigger the wheels, the faster you’ll go. Speed skaters have really big wheels. Often three of them to maximize the size that can fit beneath the boot, and also having three helps with maneuverability as well. Having four big wheels of the same huge size is possible, they will then extend further out the front and the back of the boot and end up meaning turning is a little more difficult. Imagine the difference between turning on a pair of big skis and your skates.

Another point: smaller wheels have less polyurethane and so wear out quicker, and larger wheels are generally more expensive.

So what size should you have?

80mm.

There, I said it. Well, the truth is these are the standard size wheels for recreational skates. These could also be used for freestyle skates which you use for slalom (which have a harder boot typically), these are not for aggressive skates (which have smaller wheels around 54mm to 72mm and sometimes only two wheels), and these not speed skates which have bigger wheels (like 110mm).

Actually, the true answer is it depends on your skates, and your skating proficiency. We can cover that in more detail below. Please don’t go out and randomly buy 80mm wheels without checking the below to check what your particular skates actually need…

The Hardness Of The Wheel

Hardness is the A number. This stands for durometer. And this ranges from 68A to 90A . The scale actually goes from 1 – 100 but that’s the range within skate wheels (the scale measures hardness of anything). You’ll want a soft wheel generally indoors, and harder wheels outdoors. Softer is slower. Harder is faster. Higher the number, harder the wheel.

So if you have a really soft wheel, it’s going to change shape when you put weight on it. Not really in the sort of way you can see, but at the micro level that’s what’s happening. As it changes shape, basically getting squashed underneath you, it puts more of its surface onto the ground increasing the friction and essentially giving you more grip. Of course with more friction and surface area, you go a bit slower too. We’re talking minute differences here but that’s what’s happening.

A harder wheel meanwhile will have less change in shape, keeping less of its surface area on the floor, providing slightly less grip, but allowing for greater speed. It will also slide more easily. If you wanted to go out and do a bunch of powerslides having a hard wheel would help.

A softer wheel also, like the difference between rock and cheese, will break away more easily, so small tiny parts you can barely see will rub away as you use it, especially over coarse ground like pavement. So having a softer wheel outside means it will not last as long. And if it’s really soft it might not last long at all. However, if you’re inside on a lovely smooth surface then having a really hard wheel is going to mean you’re going to slip all over the place and it might be difficult if you’re not a pro to skate well. So, on a surface like that a soft wheel is going to be better for you. Hockey skates have slightly softer wheels.

Also, someone who wants to do the exact same type of skating, say indoors on a lovely smooth surface all the time, for ten hours a week exactly, but they’re twice the weight of their friend who does the same skating, they’ll want a softer wheel on the scale of hardness, but probably up a hardness number up from their lighter friend. This is because obviously their weight is pushing down on the wheel as well, meaning it changes shape a tiny bit and wears out a tiny bit more.

Nothing below an 82A hardness or higher for outdoor. Below that is 80A, for indoors. For 190lb skating, skating an 82A hardness, is not the same as someone who’s 150lb. so remember that your weight does matter.

Sometimes FIRM and XFIRM are used instead of durometer. The higher the number the harder the wheel. Hard wheel is more durable and last longer but you’ll feel the bumps.

Worth noting though that hardness is not everywhere when it comes to speed, because these ratings only measure the hardness of the outer core part.

What About The Hub?

Refers to the centre part of the wheel where the bearings reside, there’s two basic sizes, there’s a microhub and a standard hub. The more current models only have standard hub, only old ones have the microhub.

When Should I Get New Wheels For My Inline Skates?

There’s only a couple of reasons really:

Wheels are worn down one side. Or they could be worn down both sides if you’ve been rotating them around.
You want to get better performance by changing the wheel size of hardness.
You want to change the colour so you look cool (technically you could have this reason too)

Different Wheels For Different Types Of Skating

Aggressive inline skating wheels

Aggressive inline skating favours control, the ability to accelerate quickly and room to grind along rails, over speed over long distances. So the wheels are small, hard, and have a flat profile much like skateboard wheels do.

These are 54mm and 59mm, but nowadays some are skating on slightly larger as well, up to 72mm in size. The hardness is always around 88a or 90a. These wheels are short, wide with a rounded profile and a solid core.

People sometimes put smaller wheels or no wheels in the middle to help them grind, but this is going to mean it’s harder to actualy skate around because you don’t have all four wheels helping you gain speed, more effort and energy on your part.

You can have really small rocker wheels which are for the inside two wheels which people sometimes have to help them grind, these can be around 45mm – 49.5 mm.

Recreational skating wheels

Recreational skates are between 70mm and 78mm wheels, and they have hardness between 60A and 80A. That’s because they’re outside and you want to go fast, but you’re not going crazy and odnt want to be so high off the ground so as to lose stability. They’re basically all purpose really.

Freestyle skate wheels

So these are the skates you can both skate around the city just like recreational, but you’ve better upgrade abilities via the frame and you can fit bigger wheels if you want, and these are the ones you see being used in slalom through those little cones. Slalom can be between 72 – 80mm, average height and rounded for manoeuvrability, whilst also maintaining grip.

Fitness skating wheels

So this is getting a bit more serious so you should be good by this point, able to deal with bigger wheels. 76 – 90mm for serious fitness skating, along with this taller height they have a slightly thinner profile and are made for more distance.

Speed skates

Now you’re getting into big territory. With between 90mm and 110mm, the smallest wheels are as big as the biggest fitness skate wheels. These are thin and more tapered for speed.

Hockey skates

72mm and 80mm, and 72A – 74A for maximum grip and maneuverability