Bearings & Bearing/Wheel Weight

Are you thinking of purchasing bearings for your skates? Are you confused about what kind to get? Well don’t feel like you are all alone! Skaters today have the luxury (or problem) of having many bearings to choose from. You can select bearings based on size, weight, ABEC rating, manufacturer, material content, availability, wheel compatibility and price. There are so many combinations available that it is next to impossible to compare and determine which bearing is exactly right for you.

A method presented here for bearing selection is based on weight. It is a well-known fact that at the end of an inline race that the top dozen or so finishers can finish within seconds of each other. 100ths of a second can separate 1st, 2nd and 3rd place. In this situation a skater wants any ethical advantage available to him/her. If a skater has a lighter skate than the rest of the pack then he/she can direct more energy into going fast and not moving dead weight around. The issue of skate weight is equally important to the non-racer, the fitness and recreational skater. If you are on a long trail skate and have a lighter skate then you will be able to go further expending the same amount of energy.

The total weight of your skates can be broken down into three major categories – the boot, the frame and axles, and the wheels and bearings. Each category alone makes a significant contribution to the total weight of a skate. For this discussion we are going to focus only on the bearings and wheels.

Have you heard the claim yet that a 688 bearing is 60% lighter than a 608 bearing? This is a true statement but it doesn’t tell the whole story. Before we continue, here is a primer on the different bearings that are available today.

The most common bearing, the one that has been around the longest is the 608 bearing. A single 608 bearing has an outside diameter (OD) of .865”, an inside diameter (ID) of .315”, a thickness of .276” and a weight of 11 grams (gm). A 608 bearing fits only a 608 wheel and in a 608 wheel the bearing set is comprised of two bearings and one axle spacer. This bearing set weighs 25 gm. Common names for 608 bearings include Zero Drag, Speedfreak, Ninja, Bones, Boss, Yak, Twin Cam, China, etc.

The next “new” bearing to come out was the 688 bearing or mini-bearing. A single 688 bearing has an OD of .630”, an ID of .315”, a thickness of .195” and a weight of 4 gm. A 688 bearing can fit into a 608 or 688 wheel. In a 608 wheel the bearing set is comprised of two bearings, one axle spacer and two wheel sleeves. This bearing set weighs 13 gm. In a 688 wheel the bearing set is comprised of two bearings and one axle spacer. This bearing set weighs 10 gm. Common names for 688 bearings include Micro Green, Baby Bont, Zero Drag, Ninja Mini Miser, Xenan Black Magic, Twin Cam, China, etc. Comparing an individual 688 bearing at 4 gm to a 608 bearing at 11 gm results in a weight savings of 7 gm or approximately 60%. This is where the “60% lighter” claim comes from.

A more recent bearing offering is the 698 bearing. The 698 bearing is very difficult to find and indications are that it is being phased out. The 698 bearing fits only a 698 wheel. The 698 bearing has an OD of .748”, an ID of .315” and a thickness of .236”. I could not get my hands on one to weigh nor could I find a specification sheet that gives the individual bearing weight. My guess is it falls in between the 608 and 688 bearing in size and weight. Common names for 698 bearings are Dwarf and Twin Cam. Due to lack of information further discussion of the 698 bearing is dropped.

Another recent bearing offering is what I call the “S” bearing. Common names for the “S” bearing are Bont Samurai and SinSystem. A single “S” bearing has an OD of .865”, an ID of .550”, a thickness of .195” and a weight of 6 gm. The “S” bearing fits only a 608 wheel. The bearing set is comprised of two bearings, two “top hats” and one axle spacer. The bearing set weighs 17 gm.

One also must consider the weight of the wheel when trying to get the total picture. My findings indicate that a 688 wheel is heavier than a 608 wheel.

One can see that a 688 bearing set in a 608 wheel offers the greatest weight savings followed by a 688 bearing in a 688 wheel followed by a “S” bearing in a 608 wheel.

In other words, a 688 bearing set in a 608 wheel saves 12 gm per wheel as compared to a 608 wheel with a 608 bearing set. On a pair of 5-wheel skates the total weight savings is 120 gm or .26 pounds, approximately a quarter pound.

A quarter pound might not seem like much weight but it can be the difference between finishing 1st and 10th in a race or skating one more mile on your favorite trail! Always keep in mind that the weight of your skates will impact how fast or how far you can go. The weight of the bearings and wheels on your skates can make a difference and is one of three major categories that make-up the total weight of your skates.