It is the question we answer more than any other on WhatsApp, and it is the one nobody writes about because it sounds too simple. How many bearings do I need? How many wheels come in a set? Do I need spacers, and if so how many? Is a set of eight wheels enough for a three wheel frame? Why does my friend's quad setup need a different bearing size? The questions sound basic, but get one of them wrong and you either end up with a box of parts that will not build a skate, or a second order and another week of waiting before you can roll.
This guide lays out the counting for every common speed skating layout, explains the sizes that trip people up, and shows you how a set of wheels, a set of bearings and a frame fit together into a complete pair. Every number in it comes from the product listings on our own store, so what you read here matches what arrives in the box.
The rule that everything else follows from
Every wheel needs two bearings, one on each side of the hub, with a spacer between them on the axle. That is the whole rule. Once you know how many wheels a pair of frames carries, you know everything else. Count the wheels, double it for bearings, and match it for spacers.
Where people go wrong is in the second step, which is how bearings and wheels are actually sold. Inline race wheels are sold in sets of eight, because a pair of four wheel frames carries eight wheels. Bearings from the Power Bearings range are listed as sixteen for a standard pair of four wheel skates, because eight wheels need sixteen bearings. Neither of those numbers is a coincidence, and neither of them changes just because you moved to a three wheel frame or a quad skate. So the honest answer to "how many do I need" always starts with "what are you building".
Every wheel in every layout is built like this. Count the wheels and the rest of the shopping list writes itself.
Counting by frame layout
Four wheel inline frames
This is the standard, and it is why the sets are sized the way they are. A pair of four wheel frames such as the LiveLica Aerolite 4x110 carries eight wheels. That is one set of eight wheels, sixteen bearings, and eight spacers. The Aerolite frames ship with axles and spacers in the box along with an Allen key, so for a pair of Aerolites the list is exactly one wheel set and one bearing set, nothing else. The same counting applies to the Aerolite 4x90 and 4x100, and to the Hi Lo 3x110 plus 1x100, which is still a four wheel frame even though the wheel sizes differ.
Three wheel inline frames
Here is where the first surprise lands. A pair of three wheel frames such as the LiveLica Aerolite 3x125 carries six wheels, not eight. So you need six wheels, twelve bearings and six spacers. Wheels are still sold in sets of eight and bearings as a set of sixteen for a pair, which means a triskate build leaves you with two spare wheels and four spare bearings from a standard purchase. That is not wasted money. Keep the spare wheels as a matched pair for when one wheel wears or cracks, and keep the spare bearings clean and oiled in a small tin for the day one seizes at a race. One important note: the Aerolite 3x125 takes 125mm wheels, and you should confirm the diameter your frame is built for before ordering any wheel set, because a 110mm set will not give you the rollout the frame was designed around.
Quad skates
A quad skate has two axles and four wheels per boot, so a pair carries eight wheels, the same as a four wheel inline pair. Sixteen bearings again. The difference with quads is not the count, it is the size, which we cover next, and it matters enough that skaters who get it wrong have to send a whole set back.
The counts are simple once you know the layout. The trap for triskate owners is spares, and the trap for quad skaters is bearing size.
608 or 627: the size question that sends sets back
Almost every inline speed skate runs a 608 bearing. In the Power Bearings range that is an 8mm bore, 22mm outer diameter and 7mm width, sold as the 608RS sealed version. The Power Bearings Super is a good example, an ABEC 9 precision steel bearing in the 608 size that the listing describes as the all rounder of the range for training all week and racing at the weekend. The Aerolite frames are all built for 608 bearings, and the JUNK and MPC wheels we stock are all designed around them.
Quad skates, and a small number of inline frames, use a 627 bearing instead. It has the same 22mm outer diameter and 7mm width, but the bore is 7mm rather than 8mm. Those two bearings look identical in a photo and they will not fit each other's axles. A 608 will not go onto a 7mm axle at all, and a 627 on an 8mm axle is simply impossible. If your skate runs 627, you want something like the Power Bearings 627 ABEC 11, which is built specifically for quad setups and 627 axle frames with a thermoformed nylon cage and double lumen contact seals.
How to tell which you have
Pull a wheel and look at the axle. If you have a vernier or even a decent ruler, measure the axle diameter. Eight millimetres is 608, seven millimetres is 627. If you cannot measure it, look at a bearing that is already in the wheel, because the size is usually stamped on the shield. If you still are not sure, send us a photo of the axle next to a ruler and we will confirm before you order. That one message has saved a lot of skaters a return shipment.
The outer ring is identical, which is why people buy the wrong one. Measure the axle, not the bearing.
Spacers and axles: what comes in the box and what does not
Spacers are the part most likely to be forgotten, because on a working skate you never see them. All six LiveLica Aerolite frames list spacers and axles as included along with the Allen key, so if you are buying a frame from us you do not need to buy spacers separately. If you are building onto a frame you already own, check that you have one spacer per wheel and that none are damaged, because a crushed or missing spacer lets the axle side load the bearings and that is one of the quickest ways to make a fast set of bearings feel slow.
Wheels do not include bearings or spacers. The JUNK Voodoo XFirm listing says it plainly: the wheels are sold on their own as a set of eight, and you will also need sixteen 608 bearings and spacers. That is true across the JUNK and MPC race wheels we stock. A wheel set is a wheel set, nothing more, and that is deliberate, because racers swap wheel compounds far more often than they swap bearings and do not want to pay for bearings every time.
The one product that breaks the rule
The Power Bearings Speed Minimizer is the exception worth knowing about. It is not a standard bearing set at all but a mini bearing racing system, and it comes as a matched unit with its own aluminium axles, one piece outer aluminium adaptors and in line spacers designed for the mini bearings. The adaptors are what let the smaller bearing sit in a standard wheel hub. So if you are building with the Speed Minimizer, you are not using the axles and spacers from your frame, and the counting for a four wheel pair is still sixteen bearings but the hardware around them is all supplied in the system. It is the flagship of the range and the listing is honest that it is not a sensible first upgrade, so most skaters reading this guide should build with a standard 608 set and be done.
Building a complete pair from scratch
Put it all together and the shopping list for the common builds looks like this.
- Four wheel inline pair on Aerolite frames: one frame pair, one set of eight wheels in the diameter the frame is built for, one set of sixteen 608 bearings. Spacers and axles come with the frame.
- Three wheel inline pair on the Aerolite 3x125: one frame pair, six 125mm wheels (a set of eight leaves two spares), one set of sixteen 608 bearings with four spares. Spacers and axles come with the frame.
- Quad pair: eight wheels, sixteen bearings in whichever size your axles take, which for most quads means 627. Check the axle before ordering anything.
- Any build using the Speed Minimizer: the system supplies its own axles, adaptors and spacers, so buy the wheels and the system and nothing else.
For the bearings themselves, the whole range sits in the speed bearings collection. For a first race set the listings point most new racers to Power Bearings Red as the entry into the range and Super as the improved version with ABEC 9 and higher turning precision, and the guide to the full Power Bearings range compares every set if you want to go deeper than that.
Why spares are worth planning for
Bearings and wheels do not fail on a schedule. A bearing picks up grit at an outdoor session and starts to grind. A wheel takes a chunk out of the urethane on a kerb. When that happens the night before a race, the difference between a good weekend and a wasted entry fee is whether you have a spare in the bag. Triskate owners get their spares free with a standard purchase, as explained above. Four wheel and quad skaters have to plan for them. Two spare bearings and one spare wheel of the same compound and diameter is a sensible minimum, and if you skate outdoors in Indian conditions where dust gets into everything, make it four bearings. Our guide to race day setup covers the full bag checklist.
Frequently asked questions
How many bearings do I need for a pair of inline speed skates?
Sixteen for a pair of four wheel skates, twelve for a pair of three wheel skates. Two per wheel, always.
Do wheels come with bearings?
No. JUNK and MPC race wheels are sold as a set of eight wheels only. Bearings and spacers are separate, and spacers are included with the LiveLica Aerolite frames.
I have a three wheel frame. Should I buy a set of eight wheels?
Yes, because that is how race wheels are sold, and the two extra wheels are your spares. Make sure the diameter matches your frame, which for the Aerolite 3x125 means 125mm.
What size bearing do quad skates use?
Most quads use 627, which has a 7mm bore, rather than the 8mm bore 608 used on nearly all inline speed skates. Measure the axle before you order.
Can I mix a 608 and a 627 in the same skate?
No. The bore size has to match the axle, and a skate has one axle size. Choose the bearing that fits your axle and buy the whole set in that size.
Do I need to buy spacers with a new frame?
Not with an Aerolite. All six frames in the line include spacers, axles and an Allen key in the box. With another brand of frame, check the listing or count what you have before ordering wheels.
The short version
Two bearings per wheel and one spacer between them. Eight wheels and sixteen bearings for a four wheel or quad pair, six wheels and twelve bearings for a triskate pair. Wheels come in sets of eight and never include bearings. Aerolite frames include spacers and axles. Inline uses 608, quads usually use 627, and you tell them apart by measuring the axle, not by looking at the bearing. Get those five facts right and your first order builds a complete pair of skates with no second shipment.
