Inline skates

The documented history of inline skates dates back to the early 18th century, when enterprising inventors sought to make boots roll on wheels to emulate the gliding of ice blades on dry land. Because these wheeled skates were modeled after ice blades, their wheels were arranged in a single line. Skates were simply assumed to have a single runner, whether it was a steel blade on an ice skate or a row of wheels on a wheeled skate. Wheeled skates The first patented wheeled skate was filed in France in 1819 by Charles-Louis Petibled. From that point forward, more patents and documented designs continued to explore wheeled alternatives to ice skates. It was the first double-row skate that allowed beginners to steer easily by simply leaning in the desired direction. Plimpton's invention sparked a rapid rise in roller skate popularity and spread across both sides of the Atlantic, creating a period of "rinkomania" during the 1860s and 1870s. His design also redefined the term "roller skate", which no longer referred to all wheeled skates but became synonymous with the "two-by-two" Plimpton style. After Plimpton The development of precision ball bearings in the mid-19th century helped make bicycles more efficient and practical. By the 1880s, Plimpton-style roller skates similarly incorporated ball bearings into their wheel assemblies, making skates roll more efficiently. At the same time, manufacturers began operating skating rinks as promotional ventures from the 1880s through the 1910s. All of these further fueled the Plimpton skate craze. While still in the shadow of 2x2 roller skates, some models began to gain popularity among ice hockey players by the 1960s and 1970s, due to their better emulation of ice blades. In particular, off-season training skates used by USSR speed skaters inspired Gordon Ware of the Chicago Roller Skate Company to develop and patent a wheeled skate, Both of these skate models became direct precursors to modern inline skates. In a related development, the ski boot manufacturer Lange introduced the first molded plastic ski boots with internal liners in the 1960s. In the 1970s, Lange entered the ice hockey market with similar plastic boots featuring hinged cuffs and achieved some success. Meanwhile, skateboarding reached new heights during the 1970s, thanks to the introduction of polyurethane wheels and their superior performance. The confluence of molded plastic boots with hinged cuffs, polyurethane wheels, Super Sport Skates, and the earlier Chicago Roller-Blade laid the foundation for the emergence of Rollerblade in the 1980s and its widespread appeal among the general public. Olson, his brother Brennan, his family, and his friends replaced the stock boots with customers' old hockey boots and swapped out the original wheels for polyurethane ones. This skate rolled faster, and remained more reliable on road surfaces. However, a patent search revealed that the Chicago Roller-Blade already covered many of these features. In 1981, Olson persuaded the Chicago Roller Skate Company to transfer the patent to him in exchange for a share of future profits. Thus began the modern history of inline skates, with Olson's company eventually becoming known as Rollerblade, Inc. by around 1988. The registered trademark "Rollerblade" became so well known that it entered common usage as a generic trademark. Around this time, the company began promoting the term "in-line skating" in an effort to prevent "rollerblading" from becoming a verb. The campaign proved effective, as media outlets, newspapers, and competitors adopted "in-line skating" as the preferred term by 1990. The phrase was soon shortened to "inline", the name by which these skates are known today. Modern inline skates became practical for mass production and appealing as a recreational activity once key technologies came together. These included polyurethane wheels, ISO 608 standard ball bearings, and molded plastic boots. These skates incorporate double ball bearings with dual-purpose axles from Chomin Harry (1925), single-piece frames from Christian Siffert (1938), adjustable wheel rockering from Gordon Ware (1966), single-unit boot/hockey frame with larger wheels from Maury Silver (1975), plus additional innovations. == Design and function ==

Components All modern inline skates share a common basic blueprint. A skate comprises a boot, worn on the foot. To the bottom of the boot is attached a frame, the most rigid part of the skate. The frame holds a number of wheels in place with wheel axles. In between a wheel and an axle are two bearings. Bearings allow a wheel to rotate freely around its axle. Finally, a rubber brake typically attaches to the frame of the right boot, on recreational skates. Heel lock Proper heel lock serves as a stable foundation for the entire foot. It allows a skater to adopt an athletic stance for skating by flexing the lower leg forward, without lifting the heel from the insole. A snug fit means reduced movement of the foot within the skate, and thus reduced opportunity for friction to cause blisters. At the same time, the whole skate becomes transfixed to the foot as an extension of it, allowing efficient strides with a faithful transfer of power from the foot to the ground. However, the term "heel lift" also colloquially describes a completely different condition: heel slippage - the lack of heel lock. In this case, the heel lifts off the insole when the skater flexes the shin forward, which can lead to inefficiencies and blisters. == Types ==

There are a variety of ways to design and make modern inline skates. Different types of inline skates reflect needs specific to different inline skating disciplines, such as recreational skating, urban skating, roller hockey, street hockey, speed skating, slalom skating, aggressive skating, and artistic inline skating. Manufacturers and resellers generally classify inline skates based on disciplines, such as aggressive skates, speed skates and hockey skates. Many in the community call aggressive skating "rollerblading" (or simply "blading"), and thus members "bladers". They are primarily produced by ice hockey manufacturers such as CCM, Bauer (Mission), True, and Marsblade. They are built to be as lightweight as economically feasible while still delivering excellent heel and ankle support, along with protection against impacts from flying pucks. Direct and immediate power transfer from foot to wheel is also essential. To achieve this, hockey boots are constructed around an unyielding wall with anatomical contours to hug the heel and both sides of the ankle. This structure is called the "quarter package", made of left and right quarter panels bolted to a rigid outsole platform. Speed skating differs from other inline disciplines in that a speed skater tilts her body trunk forward for up to 60° when racing, to reduce air resistance. A speed skater bends her knees aggressively for up to 80° in a deep-seated squatting position which requires a deep forward leaning of the shin (dorsiflexion) for proper balance. This deep squatting posture produces the most powerful push-offs, with the farthest displacement of the pushing skate. Freestyle skating requires skates that support rigorous turning and edging maneuvers, with characteristics similar to hockey skates. A rockered setup with wheels on a relatively short frame is common for freestyle skating. Urban skating, also known as "city commuting", takes the activity to the street. But the term "street skating" is already taken as a subdiscipline of aggressive skating, for grinding on street obstacles. Thus, this niche market is variously promoted as skating on paved roads or commuting to work on skates. These activities demand longer frames and larger wheels for higher cruising speed, stable tracking, and more comfortable rides on uneven surfaces, similar to speed skates for marathon events. Common wheel setups include 4x80mm, 4x90mm, 4x100mm, 3x100mm, 3x110mm, and 3x125mm. Most urban skate boots support either the 165mm or Trinity mounting standard, and can be customized with a short frame and average-sized wheels for slalom skating, or with a long frame and large wheels for long-distance road skating. Both the 165mm and Trinity mounting standards raise the heel mounting platform higher than the toe, creating a slight "heel-to-toe drop", also known as a heel raise. This drop causes the skater to lean forward by default, simulating a subtle forward flex similar in purpose to the hi-lo wheel setup used in hockey skates. Wizard skating is named after the company Wizard Skating, founded by Leon Basin in 2014. This form of skating is characterized by flowing footwork from freestyle, slalom, and figure skating, while a skater blazes through roads, rolls over curbs, skates up ramps, bashes down stairs, and parkours on walls. Leon perfected a type of "wizard" skate for this sport, featuring a long frame, large wheels, and a pre-rockered wheel setup for either 4 wheels or 5 wheels. Skaters increasingly refer to this style as "flow skating". == Boots ==

Hard boots Hard boots dominated the inline skate market in the 1980s and 1990s at the inception of modern inline skating, and traced their design back to plastic ski boots from Lange. They have an outer shell made of plastic, fiberglass, carbon fiber, or other solid materials. A removable liner in a hard boot provides a snug yet comfortable fit between a skater's foot and the hard shell. One-piece carbon boots In the 21st century, hockey skates increasingly favor "one-piece" carbon boots with a monocoque shell that were first developed in the 1990s for speed skating. These boots are unlike the three common types of inline boots: hard, soft and hybrid. The one-piece boots are built around a carbon fiber-reinforced composite shell, where the shell almost completely surrounds a foot. After eyelet holes are punched out of a shell, the shell is usable as a functional boot if laced. For instance, Easton's Synergy 1300C came out in 2005, with a unitary shell made with carbon and aramid fibers. This is widely recognized as the first retail hockey skate with a composite shell. Heat molding became possible in 2006, with the Easton Synergy 1500C. Other hockey makers, such as VH Hockey, took it one step further, creating a single, unbroken composite shell that also incorporates the "facing" portion where eyelets are located. leading to inline hockey skates such as the TF9 Roller Skate, and the TF Pro Custom Roller Skate in 2020. == Frames ==

An inline skate frame, sometimes referred to as the "chassis" in certain disciplines such as hockey, Rigidity of a frame is an important factor in choosing one. However, other considerations, including cost and weight, also influence the decision. Sometimes, a discipline's needs trump many of these factors. For instance, aggressive skaters exclusively use fiberglass-reinforced plastic frames for their superior performance and consistent friction when grinding against all types of surfaces. In addition, some skaters value comfort, which is at odds with rigid frames; increased rigidity transmits all imperfections of the road surface to the skater unattenuated, reducing comfort. Rockerable frames Wheel rockering can be achieved by using wheels of different diameters, or by using a frame with built-in support for a rockered arrangement of identical wheels. Such rockerable frames may be configured in either a flat setup for long-distance skating, or a banana-rockered setup for highly maneuverable disciplines like hockey, with sharp turns and quick footwork. Roces Impala skates brought the 165mm standard outside of speed skating in the mid-1990s, expanding it to recreational, aggressive, and slalom skating. However, softer soles in these boots may flex under load, prompting reinforcement with metal plates. This design provides a stable ride at high speeds by maintaining a relatively low center of gravity in proportion to the longer wheelbase. In 1998, Roces released the 5th Element, an aggressive skate that combined the soulplate and frame into a single flat unit with no height difference between front and rear. This flat sole improved soul grinds and influenced other skate designs. In 1999, Salomon, USD, Razors, Kizer, 7XL/Able, and Fifty/50 developed the Universal Frame System (UFS), a standardized mounting system for aggressive skates. It used a flat rectangular surface wide with two holes spaced apart, aligning with the trend of flat soulplates. Salomon's 2001 Aaron Feinberg Pro Model was the first skate to feature UFS and quickly became a popular industry standard. Unlike other mounting systems of the time, UFS eliminated built-in heel raise, positioning the heel level with the toes for the first time. However, most brands followed Salomon's lead in incorporating a thick shock absorber at the heel. This provided better impact support for hard landings from high jumps, but accidentally reintroduced a small amount of heel raise. Trinity frames The 165mm standard, originally from speed skating, has dominated since the mid-1990s, except in aggressive (UFS) and hockey (riveted) skates. But its small mount area can cause frame wobble on boots without stiff soles or reinforced platforms. In 2016, Powerslide introduced the Trinity mounting system to support modern wheel setups while addressing the limitations of the 165mm and 195mm standards. Unlike two-point systems, Trinity uses three mounts. The two front bolts are offset, placed beside the centerline to allow front wheels to sit closer to the sole. The rear mount, located under the heel, is raised by to clear the rear wheels and create a heel raise similar to the 165mm standard. The three bolts form a triangular layout measuring , , and . A Trinity frame typically has a lower front mount height than its 165mm counterpart when using the same wheel setup. This is because the front mount of a Trinity frame can be positioned significantly lower than the tops of the front wheels due to its open centerline, allowing the front of the boot to be moved as close to the ground as the front wheels allow. This lowers the skate's center of gravity, improving control and stability. Heel brakes and toe stops A heel brake is a hard rubber stopper attached to the back of the frame that lets skaters stop by lifting their toes and pressing the brake to the ground. It is especially important for beginners, offering a simple way to stop quickly and control downhill speed. Recreational and fitness skates usually include one brake, mountable on either skate, with most righthanded skaters choosing the right. Heel brakes can interfere with advanced techniques like crossover turns, which are essential in hockey and speed skating. They also hinder freestyle slalom tricks and aggressive grinds. As a result, skates made for racing, hockey, slalom, and aggressive skating typically do not include a heel brake. Some urban skates include an unattached brake, while others cannot support one at all. Many experienced skaters remove heel brakes after learning other stopping methods, such as the "T-stop", which uses friction from dragging one skate behind the other. However, these techniques wear down wheels, so some skaters prefer slalom moves and controlled turns to avoid obstacles and reduce wear. Inline figure skates are unique among inline designs in that they use a "toe stop" instead of a heel brake. Toe stops are essential for performing many artistic roller skating moves and jumps. == Wheels ==

Polyurethane wheels Modern inline wheels are made of polyurethane (also PU or urethane), a versatile elastomer that transformed skating. It can be molded into any shape and customized for color, hardness, grip, and elasticity, enabling specialized wheels for various skating disciplines. Polyurethane offers high elasticity, or wheel rebound, without compromising other properties. This rebound helps convert stride energy into acceleration, benefiting all types of inline skating. In the early 1980s, Scott Olson similarly repurposed polyurethane wheels from roller skates, shaving down tens of thousands to fit the skates sold by his company, Ole's Innovative Sports – later known as Rollerblade. The same qualities that made polyurethane wheels ideal for skateboarding, such as durability, impact resistance, and a smooth ride, also benefited inline skating. This innovation helped bring inline skating out of obscurity and transform it into a popular outdoor sport during the 1980s. The visible hub size varies with wheel dimensions and skating discipline. In small aggressive wheels, the hub is just a thin ring housing the bearings. In contrast, racing wheels from the 1990s had hubs taking up nearly half the diameter. By the 2020s, 110 to wheels feature hubs that occupy most of the wheel's diameter. A wheel's volume grows with the square of its diameter given fixed width. Large solid wheels would be too heavy for inline skating, so designers adopted stroller wheel concepts, using lightweight spoked hubs with interlock rims to hold the tire. These "spoked hubs", or "open cores", have an outer rim connected to the bearing housing by spokes. "Full hubs", or "closed cores", are solid discs with no visible separation. "Semi-open cores" fall in between, with solid discs and small hollows drilled to reduce weight. Wheel diameter and profile Inline skate wheels in the 2020s range from to in "wheel diameter", but the "wheel width" remains standardized at . "Small" wheels in aggressive skates, typically 55 to in diameter, often have a "flat" contact profile resembling a rounded rectangle like car tires. Most inline wheels are "medium-sized" with a "round" profile, since skaters often tilt their skates rather than always keeping them fully upright. Many techniques involve edging, or skating on the wheel sides, which requires a consistent contact surface at various angles. Balancing grip is essential. Too little grip causes slipping during strides, wasting energy. Too much grip creates rolling resistance, sapping speed during glides. In 1997, K2 patented a "dual durometer" wheel, later known as a "dual density" wheel, aimed at combining a smooth ride over rough terrain with the durability and speed of hard wheels. Unlike single-compound wheels, it used two polyurethane layers: a hard outer tire (70A to 100A) for wear resistance and speed, and a soft inner ring (20A to 75A) to absorb shocks and vibrations. Rolling resistance Rolling resistance (also rolling friction or drag) is a key factor limiting a skater's top speed. It opposes wheel motion and is mainly caused by elastic hysteresis. == Bearings ==

Ball bearings allow inline skate wheels to spin freely by separating the moving wheels from the non-moving structure. Similarly, TWINCAM bearings were created in the early 1990s specifically for inline skating, marketed with the slogan “Beyond ABEC”. In 1991, they introduced serviceable bearings with removable shields held in place with a C-clip, followed in 1992 by TK CLASSIC Racing Gel, a water-repellent lubricant. In 2002, they launched the ILQ-9, a 6-ball bearing, as an alternative to the standard 7-ball setup. The ILQ line later expanded to include models such as ILQ-9 Pro with rubber shields, ILQ-7 for OEM skates, ILQ-X mr2 with reduced weight, and ILQ-Midget with 11 balls. TWINCAM trademarked "ILQ" (InLine Qualified) as a proprietary rating system, and had various ILQ models rebranded and redistributed by partners such as FR Skates, K2, Rollerblade, and Powerslide/Wicked. Contamination and bearing friction Skaters lose energy not only from wheel rolling resistance but also from bearing friction, caused by internal components like balls, cage, lubricant, and seals. However, in clean, well-lubricated bearings, this friction is minimal compared to rolling resistance of polyurethane wheels. Most purpose-built bearings from reputable brands meet or exceed ABEC 3 specs, so bearing selection has little effect on performance when bearings are new. Bearing selection plays a significant role over the lifetime of bearings, however, because performance depends on how well bearings resist contamination from dirt, dust, and moisture. Even microscopic particles can damage raceways and hinder smooth rotation. Contamination is the most harmful factor; it reduces efficiency or causes bearings to seize. As skaters say, the fastest bearings in the world are simply ones that are new or freshly cleaned and lubricated. Bearing shields Inline skate bearings are protected from contamination using four main shield types: (Z) non-serviceable metal gap shields, (ZS) serviceable metal gap shields with a C-ring, (RS) serviceable rubber gap shields bonded to a metal insert, and (RSL) full-contact labyrinth rubber lip seals. Z shields: simple metal covers that snap into the outer race without touching the inner race, leaving a small non-contact gap. They create no drag but offer limited protection and cannot be removed without damage. Bearings with shields on both sides are labeled "ZZ" and are non-serviceable (e.g., Rollerblade SG). ZS shields: similar to Z shields, but feature a removable C-clip (C-ring), allowing for easy shield removal for maintenance. They are similarly non-contact and low-drag, and similarly provide minimal defense against dirt and moisture. Their main advantage is serviceability: that skaters can remove and reattach the shields without damage, enabling regular cleaning and relubrication. This design is used in TWINCAM ILQ-style bearings, with double-shielded ones often labeled "2ZS" or "ZZS". RS shields: use a nitrile rubber shield bonded to a metal insert. In skating, RS rubber shields specifically refer to the design popularized by Bones Swiss. They offer better protection than Z or ZS shields and are removable for cleaning and maintenance. Many skate brands use only one RS shield, leaving the inner side open and protected by the wheel hub, allowing easy lubrication access without even removing the shield. RSL seals: full-contact rubber seals with a labyrinth lip profile that lightly touches the inner race, blocking dirt and moisture. These are used with "thick grease" for long-lasting protection with "near-zero maintenance", but cause more "bearing drag". Though they don't spin freely when unloaded, they perform efficiently under a skater's weight, when grease is forced away from ball paths as wheels roll. Dragon Bearings produces "2RSL" models with RSL seals on both sides. == Skate tuning ==

Skate setup, customization and tuning terms vary by discipline. For instance, urban skaters refers to four larger wheels (e.g. 4x90mm) and triskates with three large wheels ( or more) as "big-wheel setups". In contrast, aggressive skaters consider anything or larger to be big-wheel. On the other hand, large wheels are standard for marathon skaters, and a triskate under is seen as small and unusual. Terms like "big-wheel" and "triskate" also imply specific frame and boot designs, as setups with wheels need stronger frames and more supportive boots to handle increased speed and leverage. A "frame assembly" refers to all skate components except the boot and wheel assemblies. For recreational skates, this includes the frame, brake, boot-mounting hardware, and axle assemblies. In aggressive skates, it may also include H-blocks and parts for grinding. Wheel rotation Inline skate wheels wear down with use and need periodic "rotation" and eventual "replacement". Front wheels and inside edges wear faster, especially on the dominant foot, thus usually the right foot for right-handed skaters. Uneven wear can distort the wheel profile, and severely worn wheels risk de-coring (disbonding from wheel hub) during use. Regular wheel rotation helps distribute wear evenly, extending lifespan of the entire set. This includes "repositioning" less-worn wheels to high-wear axles to balance diameter differences, "flipping" wheels to even out lopsided edge wear from motions such as push-offs, and "swapping" wheels between skates to address asymmetrical wear from foot dominance. In the 1980s, Rollerblade and Kryptonics developed plastic hubs with precise, rigid "bearing seats" to align bearings accurately. Each deep "bearing recess" matches the width of an ISO 608 bearing, allowing flush mounting with press-fit. This leaves a gap between two bearings mounted on a hub standardized at wide. This gap is filled by a "bearing abutment" molded into the hub to position and support the bearings. A ball bearing has two concentric races that rotate relative to each other. The outer race is secured to the hub and rotates with the wheel, while the inner race stays stationary with the axle assembly. A "spacer" matching the bearing abutment fits between the inner races. Tightening the axle bolt clamps the frame around the bearing assembly, creating a rigid structure that binds the axle, spacer, and inner races, securing them to the frame and boot. The bearing abutment and outer race of each bearing together define a "bearing plane". Both planes should be parallel and exactly apart, with the spacer and inner races meeting at these same planes. Proper "bearing alignment" means all these geometric relationships are correctly maintained. Side load support ISO 608 bearings in inline skates are deep groove ball bearings (radial ball bearings), designed primarily to handle radial loads - forces applied perpendicular to the axle from the skater's weight. These loads pass from the boot through the frame and axles to the inner races and balls, pressing against the outer races. Radial load in skating is thus colloquially known as "vertical load". Radial ball bearings are also capable of handling a certain amount of axial load from both directions. These are side forces along the axle produced by maneuvers that involve a deep edge, such as turning, crossovers, power slides, power stops, and techniques like slalom or the double push. Axial load in skating is colloquially known as "side load". Some purpose-built bearings, such as the Bones Swiss, are designed with larger internal clearance (gaps between the balls and raceways) to better accommodate side loading. This enables increased "axial play" (or axial clearance), an intentional design and not a sign of lower precision. It allows the inner race to shift laterally relative to the outer race, changing the contact angle between balls and raceways to better support axial loads without binding. Bearing preload Greater internal clearance in skate bearings helps prevent binding during side-loading maneuvers. However, it creates an uneven load distribution, with only the bottom ball and its neighbors supporting the skater's weight. These form the "load-bearing zone", while the other balls remain unloaded. As balls rotate through the bearing, they briefly enter the load-bearing zone and endure stress beyond their design limits, accelerating wear. At the top of rotation, balls lose contact due to clearance gaps, causing skidding, noise, energy loss, and more wear. Uneven surfaces add shifting forces that, combined with the clearance, cause axle vibrations and worsen bearing misalignment. Bearing preload in inline skates refers to a specific type of axial load - that from clamping the inner race against a properly sized spacer using the axle bolt, pre-tensioning the bearing balls at an oblique contact angle. This reduces or removes internal clearance, keeping all balls engaged and evenly distributing the skater's weight during wheel rotation. Spacer length Preloading is especially useful in high-speed skating, like downhill racing, where it removes clearance gaps, reduces skidding, and minimizes axle displacement. This improves wheel assembly's structural rigidity, and increases skater's stability, precision and control. By using a correctly sized spacer, the axle bolt can apply just enough tension to create a slight negative internal clearance (around ), the "optimal preload". This delivers optimal load distribution and load-carrying capacity, minimizing wear and maximizing bearing lifespan. Short spacer: Manufacturing imperfections often prevent spacers from perfectly matching the bearing abutment length. If a spacer is too short, overtightening the axle bolt beyond the optimal preload tension can create excessive negative clearance, increasing friction and drastically reducing bearing lifespan. In severe cases, it may cause the bearing balls to bind and lock the wheels. To address this, aluminum spacers are made in various lengths so skaters can match them to each wheel's exact dimensions. Loose axle: To fix over-tension from short spacers, some skaters mistakenly loosen axle bolts, thinking it relieves excess preload. While this may let wheels spin freely, it causes the spacers and inner races to rattle and skid, producing clunking sounds. The inner races are no longer clamped, leading to bearing misalignment and excessive wear from side loads. This creates cycles of over-preload and under-tension, worsening damage. Omitting spacers exacerbates the issue, potentially causing bearings to explode under strong side forces. Long spacer: If a perfect spacer isn't available, a slightly longer spacer is preferred over a shorter one, to avoid over-tension and excessive bearing wear. While a longer spacer prevents preload by not pushing outer races against bearing abutments, it still allows the inner races and spacer to be securely clamped. Without preload, however, the outer races rely solely on press-fit against the bearing recesses, which may not hold under side loads. This can cause the outer races to shift, wear the hub's bearing recess, and lead to lateral wheel movement and clicking sounds during skating. == Wheel setup ==

Wheel setup can refer to various aspects related to the selection and configuration of wheels. The total number of wheels and their diameter are often expressed in the form {number of wheels} x {wheel diameter in mm}. For instance, a common recreational skate setup is 4x80mm, which means four wheels, each with a diameter of 80 millimeters. Wheel arrangement patterns are typically named according to the profile formed by the wheels at their contact points with the ground. In a flat setup, all wheels maintain contact with the ground simultaneously. A classic rockered setup, by contrast, creates a banana-like profile along the bottom. Another example is the Ninja NN 90 frame from NN Skates, which also features a pre-rockered design. It introduces NN Skates' proprietary "V.m Rocker", short for "modified V Rocker". The 165mm and Trinity versions come with built-in forward lean. All of these "pre-rockered frames" are variations of the full rockered setup, combined with built-in forward flex. However, they are sometimes marketed using simplified illustrations that "horizon-correct" the top surface of the frame, showing the boot level and the skate pivoting primarily on the third wheel. This artificial stance is often described as a "V-shaped" wheel-contact profile, a "V rocker", or a "3rd-wheel down" configuration. In practice, however, skaters do not glide on a single wheel. Instead, they roll on two wheels at a time, such as the 2nd and 3rd, where the boot naturally tilts forward like a hi-lo setup. Some skaters therefore refer to this combination of forward pitch and rocker as the "hi-lo rocker" or "full hi-lo rocker". However, these terms can be confusing, especially since "hi-lo rocker" is also used colloquially to describe standard hi-lo setups. At present, there is no consistent term for this combination of banana rocker and forward lean in a pre-rockered frame. Anti-rocker setup The anti-rocker setup is the most widely used wheel configuration in aggressive skates. It gets its name from being the opposite of a rockered setup. In an anti-rocker configuration, the two middle wheels are raised off the ground, leaving only the front and rear wheels to make contact on flat surfaces. The middle wheels are typically spaced farther apart than in standard four-wheel setups, and are often made of harder materials with minimal grip. These hard wheels are commonly referred to as grindwheels, antirockers, or anti-rocker wheels. They are designed for one task alone: to make grinding on ledges and rails easier. Freestyle setup The freestyle setup is another wheel configuration favored by aggressive skaters. Despite the name, it is unrelated to freestyle slalom around cones or freestyle skating on flat ground free of street obstacles. This setup features only two outer wheels, with the middle portion of the frame replaced by solid material that resembles an extended H-block, optimized for grinding. Fifty-50's Balance Frame introduced a convertible design that can use either grindwheels or juice blocks in the center. When juice blocks are installed as grind blocks, they fill the space between the frame walls, extending the H-block to form a smooth, solid grinding surface. This transforms the Balance Frame from an anti-rocker setup into a freestyle setup. ==See also==