'Inline skates' (often called Rollerblades after the popular trade name) are a type of roller skate used for inline skating. Unlike quad skates, which are configured with two front and two rear wheels, inline skates have two, three, four or five wheels arranged in a single line. Some inline skates, especially those used for recreation, have a "stop" or "brake" which is used to slow down while skating; most inline skates have a heel stop rather than the toe stop, particularly indispensable for inline figure skating. The earliest roller skates were of the inline design, but these were later superseded by quad skates, the design of which made skating curved edges easier.
The modern style of inline skates were developed as a substitute for ice skates, for use by a Russian athlete training on solid ground for Olympic long track speed skating events. Life magazine published a photo of American skater Eric Heiden, training for the 1980 Olympics, using such skates on a Wisconsin road.
During the late 1980s and early 1990s, Rollerblade, Inc., a company founded by Scott and Brennan Olson in Minneapolis, Minnesota, widely promoted inline skating; they were so successful that their trademarked name Rollerblade became synonymous with inline skates.
A skate is composed of a boot, which is worn on the foot. To the boot is attached a frame, which holds the wheels in place. Bearings allow the wheels to rotate freely around an axle. Finally, the rubber brake typically attaches to the frame of the right foot.
An inline skate designed for artistic roller skating
There are different types of inline skates for different types of skating such as aggressive skating, speed skating, Inline hockey and artistic inline skating. Those differ in the boots, frames and wheels that are used.
For most skating a high boot is used, which provides more ankle support and is easier to skate in, particularly for beginners. Speed skaters often use a carbon fiber boot which provides greater support with a lower cut allowing more ankle flexion. For recreational skating a soft boot is used for greater comfort, but many other disciplines prefer a harder boot, either to protect the foot against impact or for better control of the skate. The boot may also contain shock absorbent padding for comfort.
Most aggressive skates use a hard boot or a hard/soft boot for increased support.
The frame and wheels of an inline skate.
Typical recreational skates use frames built out of high-grade polyurethane (plastic). Low-end department or toy store skate frames may be composed of other types of plastic. Speed skate frames are usually built out of carbon fibre or extruded aluminum (more expensive but more solid), magnesium, or even pressed aluminum, which is then folded into a frame (cheaper but less sturdy).
Carbon fibre frames are expensive but more flexible, making for a smoother ride at the expense of worse power transfer between the leg and the wheels. In general, carbon fibre frames weigh about 160-180 grams. Aluminum can weigh from 170 to 220 grams. Frame length ranges from around 230 mm for short-framed four wheel skates (used for example in inline hockey), up to about 325 mm for a five wheel racing frame.
Axles, bearings and spacers.
Ball bearings allow the wheels to rotate freely and smoothly. Bearings are usually rated on the ABEC scale, a measure of the manufactured precision tolerance, ranging from 1 (worst) to 11 (best) in odd numbers. The ABEC standards were originally intended for high-speed machinery, not skating applications, and do not account for the quality of steel used, which is also important. While higher rated bearings are generally better in overall quality, whether they automatically translate to more speed is questionable.
The vast majority of skate bearings on the market are produced in China, and tend to be of much lower quality and durability than bearings produced in Japan, Germany, Switzerland, Canada, or the USA. Newer bearings on the market now use ceramic ball bearings instead of steel, the merits of which have yet to be determined.
Diagram of inline skate wheels with different diameter and profile.
Wheel sizes vary depending on the skating style:
- 44-59 mm for aggressive skating.
- 68-72 mm for artistic inline skating.
- 47-80 mm for roller hockey skating.
- 72-80 mm for freestyle slalom skating.
- 72-90 mm for general recreational skating.
- 84-110 mm for speed skating.
Wheels are nowadays almost universally made of polyurethane (a kind of durable plastic). Most other plastics and rubber either wear down too quickly or have too much roll resistance. In general, the bigger the wheel, the faster the skate. However, large wheels take more energy to start rolling. Smaller wheels allow faster acceleration, maneuverability, and a lower center of gravity. Wheel hardness is measured on the A scale (see Durometer) and usually ranges between 78A-93A (higher numbers are harder). Harder wheels are faster and more durable, but soft wheels may have better grip (grip is determined by many factors, and wheel manufacture is arguably more important than durometer) and less affected by road bumps. Wheel profiles and thicknesses again vary by application. Elliptic profiles minimise friction for a faster ride; more rounded profiles have better grip and are more stable.
A brake allows the skater to stop by moving his foot. A hard rubber brake is typically attached to the heel of the frame. Learning how to use the heel brake thus is crucial for beginners.
Heel brakes can interfere with a useful technique called crossover turn, in which a skater crosses one leg over another to make a sharp turn without losing much speed; for this reason, some users prefer not to use heel brakes. Skaters in the freestyle slalom and Aggressive inline skating disciplines also tend not to use heel brakes, since they can limit the skater's ability to perform tricks effectively. Most aggressive inline skates and racing skates do not have a heel brake for extra speed and control, people wearing inline skates with no heel brake can use various other methods to stop such as the T-Stop (which consists of making on skate perpendicular to the other making a "T" shape to increase friction and slow the rider down)
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