There is one mistake quad skaters make more than any other when buying bearings, and it costs them a delivery and a fortnight of waiting. They order a set of 608 bearings because that is what every skate shop sells and every article talks about, the box arrives, and the bearings will not go onto the axle. The reason is simple. Many quad setups run 627 axles, not 608, and although the two bearings look almost identical in a photograph, they are not interchangeable.
This guide is written for quad skaters. It explains exactly what separates a 627 from a 608, how to check which one your skates need before you spend anything, how many bearings a quad setup actually takes, and how the two 627 options in the Power Bearings range compare so you can pick the right one for your skating. If you skate quads and you have ever squinted at a bearing wondering why it will not seat, this is the article for you.
Why quad skaters have to check first
Almost all inline speed skates use the 608 bearing, and because inline dominates the speed skating conversation, 608 has become the default assumption everywhere. Quad skating sits outside that default. A great many quad setups, including quad speed and quad long distance skates, are built around a 627 axle instead. That single difference means a large share of the bearings marketed to speed skaters simply will not fit a quad skate.
None of this is a problem once you know about it. It only becomes a problem when a skater assumes that a bearing is a bearing. Check your axle size once, write it down, and you will never order the wrong set again.
The one number that matters, the bore
The bore is the hole in the middle of the bearing, the part that slides onto the axle. That is where 627 and 608 differ. A 627 bearing measures 7mm bore by 22mm outer diameter by 7mm wide. The common 608 differs by having an 8mm bore. That one millimetre is the whole story. A 627 will not slide onto an 8mm axle, and a 608 will rattle loosely on a 7mm one.
Because the outside of the two bearings is so similar, you cannot reliably tell them apart by eye across a table. The names give it away, and so does the axle, which is why measuring or checking your frame specification is the only dependable method.
Only the bore changes. That single millimetre decides whether the bearing fits your axle at all.
How many bearings a quad setup needs
Once you have the right size, the next question is quantity, and quad skaters sometimes order half of what they need. Every wheel takes two bearings, one on each side, so the wheel spins evenly on the axle. A quad skate carries four wheels, which means eight bearings per skate. A pair of skates therefore needs sixteen bearings in total.
Two bearings per wheel, four wheels per skate, two skates. Sixteen is the number to order.
The steel option, Power Bearings 627 ABEC 11
The Power Bearings 627 ABEC 11 is the steel choice for skaters on 627 axles and a favourite for quad skating. It sits at the precision end of the steel range, pairing an ABEC 11 rating with P6 turning precision for a smooth, efficient roll.
The details matter more than the headline number. A thermoformed nylon cage holds each ball accurately in the raceway, which improves how the bearing performs and extends its working life. Double lumen contact seals on polished rims give an almost frictionless shield against dust and contamination, so the bearing keeps running clean and fast as conditions change through a session. For most quad skaters, from club level through to serious training, this is a thoroughly capable bearing.
The ceramic option, Swiss Ceramic 627
The Power Bearings Swiss Ceramic 627 is the quad version of the top tier Swiss Ceramic, built for quad speed skating and quad long distance racing. It uses a high grade Si3N4 hybrid ceramic ball. According to the manufacturer, the ceramic is around 50 percent lighter than steel yet 40 percent more robust, runs up to 100,000 rpm under load, and saves 0.8 to 1.0 watts per bearing against typical precision steel. Across sixteen bearings over a long race, that saving adds up.
It shares the same careful construction, with a nylon thermo molded cage positioning each ball and double lumen seals on polished rims shielding against dust and water. The Si3N4 is cryogenically treated at minus 300 degrees Fahrenheit to refine its structure for efficiency and durability. If you race quads over distance and want every advantage available, this is the bearing built for it.
Both are 627, so both fit a quad axle. The choice is about how hard and how far you race.
What ABEC actually tells you
ABEC ratings cause a lot of confusion, so it is worth being clear. ABEC measures manufacturing tolerance, so a higher number means the bearing was made to tighter tolerances. What it does not do is describe everything that decides how a bearing feels underfoot. Cage design, seal quality, ball material and how well the bearing is maintained all matter alongside the rating. That is why the 627 ABEC 11 lists its P6 precision, nylon cage and sealing rather than leaning on the ABEC number alone. Treat ABEC as one useful piece of information, not the whole verdict.
Fitting and looking after them
Once you have the right size and quantity, the rest is straightforward. Seat two bearings into each wheel with a spacer between them, slide the wheel onto the axle and tighten so the wheel spins freely without side to side play. Overtightening is the most common setup error and will slow you down more than any rating will speed you up.
Maintenance keeps a good bearing good. Sealed bearings resist dust and water well, but no seal is permanent, and grit that gets past will grind away your roll. Clean them when they start sounding dry or feeling slow, and re oil them with a light, clean oil such as Speedslick Pro Bearing Oil. Ceramic handles heat and water better than steel, but it still needs clean oil to run at its best.
Which one should you buy
If you skate quads regularly, train at club level and want a precise, well sealed bearing that will last, the steel 627 ABEC 11 is the sensible pick. If you race quads, especially over long distance, and you want the lightest, most efficient option available on a 627 axle, the Swiss Ceramic 627 is built for exactly that. Both fit the same axle, so the decision is purely about how hard you push them.
If it turns out your skates are on 608 rather than 627, you are not stuck. The same Swiss Ceramic is made in a 608 version, and you can see every option side by side in the speed bearings collection.
Frequently asked questions
How do I check whether my skates use 627 or 608?
Look at the axle diameter or your frame and plate specification. A 627 axle is 7mm and a 608 axle is 8mm. If you have an old bearing to hand, the size is usually printed on it. If you are still unsure, message us before ordering.
Can I make a 608 bearing fit a 627 axle?
No. A 608 has an 8mm bore and will sit loose on a 7mm axle, which is unsafe and will damage the bearing. Always match the bearing to the axle rather than trying to adapt it.
How many bearings do I need for my quads?
Sixteen for a standard pair of four wheel skates, since each wheel takes two bearings and each skate has four wheels.
Do ceramic bearings need oiling?
Yes. Ceramic copes with heat and water better than steel, but it still needs clean, light oil to run at its best. Do not assume ceramic means maintenance free.
Is a higher ABEC number always faster?
Not on its own. ABEC describes manufacturing tolerance, not real world speed. Seals, cage design, ball material, lubrication and how clean you keep the bearing all affect how fast you actually roll.
