The wheels of roller skates usually include three types, namely PVC plastic wheels, PU polyurethane wheels and rubber wheels.
PVC plastic wheels have high hardness, no shock absorption and grip, and poor damage resistance; PU polyurethane wheels have good heat resistance and wear resistance, and at the same time have good elasticity, most roller skates for women use PU wheels; rubber wheels have high elasticity , cushioning and shock absorption, and comfort is also better, but compared with the other two types of wheels, the rubber wheel has a shorter life and will change due to changes in environmental conditions.
The size and hardness of the wheel will be actively marked on the wheels of regular roller skates. The size is generally expressed in millimeters (mm), and the hardness is generally expressed by the capital letter “A”. The larger the number, the larger the wheel, and the higher the hardness.
Generally speaking, the size and hardness of the wheels of leisure roller skates are 72~76mm and 78A~80A respectively; the size of the wheels of speed skating shoes is mostly 80mm, and the hardness is generally 78A~85A; the size of the wheels of extreme roller skates is generally small wheels below 65mm, The hardness is 88A~100A.
Bearings are metal objects placed in the middle of a roller skate wheel to help help the wheel turn. A bearing should be placed on both sides of each wheel, separated by a sleeve in the middle. Generally, single-row shoes use plastic sleeves, and more advanced ones will use metal sleeves. Metal sleeves have less friction and can give the bearings maximum continuous rotation. capacity, so the wheels can turn to higher speeds.
Good bearings should be delicate and delicate in workmanship and look very smooth. Both bearing caps should be marked with the brand name and the words “608ZZABEC-X”, which is the 608 bearing currently used in single-row roller skates, of which 60 means the outer bearing of the bearing. The circumference of the ring is 60mm, 8 is the inner ring diameter of 8mm, Z is the meaning of the metal dust cover, ZZ is the metal dust cover on both sides, ABEC is the seven-ball specification bearing tolerance grade (grades 1, 3, 5, 7), the general casual single row roller skates mostly use ABEC3~5 grade general bearings.
In addition, ILQ is the tolerance grade of six-ball specification bearings (grades 7 and 9), and there is another SG grade bearing, SG-7.SG-9, which is patented by Rollerblade. Generally, the higher the rear parameters of the same brand bearing, the better the bearing precision, but the bearings of different brands and different tolerance standards generally cannot be compared horizontally.