Editing Inline skates (section)

=== Polyurethane wheels ===

{{multiple image
 | direction = horizontal
 | total_width = 380
 | image1 = USSR inline skate-from 1962-by alextreme-wheels.jpg
 | image2 = Official Roller Derby Skates-w Clay composition wheels-single view four wheels A-IMG 6452-bg-FRD.png
 | footer = Composition wheels: inline (1962) & quad (1970s)
}}

Modern inline wheels are made of [[polyurethane]], a material that revolutionized skating. Before the widespread adoption polyurethane, roller skates and skateboards used composition wheels made from clay or rubber mixed with sawdust and other fibers. These composition wheels were prone to swelling from moisture and could shatter on impact, contributing to a decline in skateboarding by the late 1960s.<ref name=Shevelson-golden-days-of-skating/><ref name="hickok-sports-history-roller-skating-1-development">{{cite web
|url=http://hickoksports.com/history/rollerskate01.shtml
|title=Roller Skating 1: Development of the Skate
|website=Hickok Sports - Sports History
|url-status=dead
|archive-url=https://web.archive.org/web/20100401173914/http://hickoksports.com:80/history/rollerskate01.shtml
|archive-date=2010-04-01
|access-date=2025-03-08
}}</ref><ref name="raybestos-composition-wheel-patent-1953">{{Cite patent
|country=US
|number=2664317
|fdate=1951-04-11
|pubdate=1953-12-29
|gdate=1953-12-29
|title=Composition roller skate wheel
|inventor1-first=Glynn
|inventor1-last=Thomas
|inventor2-first=John W
|inventor2-last=Cleever
|assign1=Raybestos Manhattan Inc
}}</ref><ref name="vegter-everthing-about-wheels"/>{{efn-ua|1=Roller Derby made clay composition wheels in the 1960s for their "sidewalk surfboards" (skateboards).<ref>{{cite web
|url=https://www.museumofplay.org/blog/sidewalk-surfing-the-gnarly-history-of-skateboarding-part-i-1940s-to-1972/
|title=Sidewalk Surfing: The Gnarly History of Skateboarding Part I (1940s to 1972)
|date=2018-06-07
|first1=Tara
|last1=Winner
|website=The Strong - National Museum of Play
|url-status=live
|archive-url=https://web.archive.org/web/20250316165159/https://www.museumofplay.org/blog/sidewalk-surfing-the-gnarly-history-of-skateboarding-part-i-1940s-to-1972/
|archive-date=2025-03-16
|access-date=2025-03-16
}}</ref><ref>{{cite web
|url=https://overplywood.wordpress.com/2013/02/28/mains-skateboard-collection-and-the-paul-conibear-ramprocker/
|title=Main’s skateboard collection and the Paul Conibear Ramprocker.
|date=2013-02-28
|website=Overplywood - The History of Skateboarding in Swansea
|url-status=live
|archive-url=https://web.archive.org/web/20250316163226/https://overplywood.wordpress.com/2013/02/28/mains-skateboard-collection-and-the-paul-conibear-ramprocker/
|archive-date=2025-03-16
|access-date=2025-03-16
}}</ref> The same wheels were used in their Royal Sidewalk line of roller skates as late as 1974 ([https://web.archive.org/web/20220422040717/https://metvcdn.metv.com/56GtX-1443477523-blog-18.jpg archived catalog page]). By 1978, however, the same Royal Sidewalk line adopted polyurethane wheels under the brand Fireball ([https://web.archive.org/web/20250316181818/https://christmas.musetechnical.com/ShowCatalogPage/1978-Sears-Christmas-Book/0436 archived catalog page]). See archived entry and images of this Etsy listing showing a pair of Royal Sidewalk skates with these clay wheels: [https://web.archive.org/web/20250316163216/https://www.etsy.com/listing/1067326122/vintage-blue-the-royal-official-roller?show_sold_out_detail=1&ref=nla_listing_details listing page], [https://web.archive.org/web/20250316163350/https://i.etsystatic.com/7671864/r/il/548df3/3363673243/il_1588xN.3363673243_kaxv.jpg image 1], and [https://web.archive.org/web/20250316163606/https://i.etsystatic.com/7671864/r/il/bf1893/3315980316/il_1588xN.3315980316_2mbv.jpg image 2].}}

{{multiple image
 | direction = horizontal
 | image1 = First Rollerblade brand inline skates with round heel brake-from early 1980s-IMG 5980-Rockerable Frame view-FRD.png
 | image2 = Kryptonics Classic skateboard polyurethane wheel glowing against sunset.jpg
 | width1 = 180
 | width2 = 180
 | footer = Urethane wheels: inline (1980s) & skateboard (2010)
}}

In the early 1970s, roller skaters experimented with polyurethane wheels, but they proved too grippy and slow for roller rinks with wooden floors, where composition wheels performed better. However, by the mid-1970s, skateboarders repurposed polyurethane wheels from roller skates, shaving them down to fit skateboards. These wheels excelled on streets and urban terrain, offering greater durability and impact resistance compared to their predecessors. Their elasticity provided a smoother ride over rough surfaces, helping to spark a resurgence in skateboarding after its late-1960s slump.<ref>{{cite web
|url=https://www.chicagoskates.com/pages/timeline
|title=Chicago Skates Timeline
|website=Chicago Skates (Chicago Roller Skates)
|url-status=live
|archive-url=https://web.archive.org/web/20240916084705/https://www.chicagoskates.com/pages/timeline
|archive-date=2024-09-16
|access-date=2025-03-08
}}</ref><ref name="washingtonpost-reinvention-of-wheel-2004"/><ref name="custompolyurethane-polyurethane-skateboard-wheels">{{cite web
|url=https://custompolyurethane.co.uk/blog/polyurethane-skateboard-wheels/
|title=Are Polyurethane Skateboard Wheels Good?
|date=2022-08-24
|website=Custom Moulded Polyurethane
|url-status=live
|archive-url=https://web.archive.org/web/20250308182122/https://custompolyurethane.co.uk/blog/polyurethane-skateboard-wheels/
|archive-date=2025-03-08
|access-date=2025-03-08
}}</ref>

{{multiple image
 | direction = horizontal
 | total_width = 340
 | image1 = Aggressive Inline Skate-Gawds-Symetrics-Dead Wheels-Bottom view-by IG Simply Vic-bg rotated.png
 | image2 = Powerslide Reign Ares hybrid skates-on Ego SL frame and Trident 100mm wheels-side-view-IMG 4721-bg-FRD.png
 | caption1 = Small & hard wheels 
 | caption2 = large & soft wheels 
}}

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.<ref name="bernstein-minnesota-hockey-inline"/><ref name="MIA-olson-inventive-impulse"/><ref name=Shevelson-golden-days-of-skating/><ref name="le-roller-en-ligne-on-inline-wheels"/>

What truly set [[polyurethane]] (or urethane) apart from previous wheel materials was its versatility. As an [[elastomer]], it could be molded into any shape and formulated to achieve a wide range of properties including color, hardness, grippiness and rebound. This adaptability allowed for the development of specialized wheels for different inline skating disciplines, from large, hard wheels with pointed bullet profiles for outdoor racing to small, soft wheels with rounded profiles for indoor hockey.<ref>{{cite web
|url=https://gallaghercorp.com/urethane-vs-polyurethane/
|title=Urethane vs. Polyurethane
|website=Gallagher Corporation
|others=quote: "when discussing industrial applications, urethane and polyurethane are essentially the same material. The terms are used interchangeably, and there is no functional difference between them."
|url-status=live
|archive-url=https://web.archive.org/web/20250309011902/https://gallaghercorp.com/urethane-vs-polyurethane/
|archive-date=2025-03-09
|access-date=2025-03-09
}}</ref><ref name="le-roller-en-ligne-on-inline-wheels"/><ref name="powell-svensson-inline-skating"/>{{rp|20–26}}{{efn-ua|name=ricardo-lino-with-tony-gabriel-tour-wheel-factory-notes|Ricardo Lino toured the factory floor of Aend Industries, a polyurethane wheel factory, with co-owner Tony Gabriel. Discussions cover all aspects of wheel-making, including history of the company, co-ownership with Neil Piper, machines bought from Tom Peterson, brands they OEM for, injection molding of hubs (cores), trimming of hubs, polyurethane coloring, urethane bonding, dual-density urethane, hardness vs grippiness, hardness vs profile, heating of urethane before pouring, casting urethane into molds, baking after casting, cutting/shaving wheels to final profile, quality control, washing, printing, and packaging.<ref name="ricardo-lino-with-tony-gabriel-tour-wheel-factory">{{cite web
|url=https://www.youtube.com/watch?v=GW8Hfj6TRDk
|first1=Ricardo
|last1=Lino
|title=This Factory Makes the Best Wheels for Inline & Quad Skating, Skateboarding & Scooters
|date=2022-06-23
|others=See video transcript for a tour of factory floor and discussions on all aspects of wheel-making.
|website=youtube.com
|language=en
|format=video
}}</ref>}}

{{multiple image
 | total_width = 300
 | direction = horizontal
 | image1 = Skate - Flickr - digicla.jpg
 | image2 = Amsterdam - Vondelpark - 1466.jpg
 | image3 = Ricossa Alice (Style Slalom) - cropped.jpg
 | footer = Rebound improves performance
}}

Another remarkable aspect of a polyurethane compound is that it can be formulated to achieve high [[Elasticity (physics)|elasticity]], regardless of the desired values for other properties such as hardness. In material science, this elasticity is often measured with the [[Bayshore Resilience]] test. In the inline skating industry, it is referred to as '''wheel rebound'''. A wheel with high rebound efficiently converts energy from a skater's stride into acceleration, while a wheel with low rebound dissipates much of that energy, leaving little to propel the skater forward. High-rebound wheels are beneficial across all inline skating disciplines, enhancing performance and efficiency.<ref name="gallaghercorp-polyurethane-resilience-elasticity-rebound">{{cite web
|url=https://gallaghercorp.com/white-papers-polyurethane-resilience/
|title=Polyurethane-Resilience
|website=Gallagher Corporation
|url-status=live
|archive-url=https://web.archive.org/web/20240803071827/https://gallaghercorp.com/white-papers-polyurethane-resilience/
|archive-date=2024-08-03
|access-date=2025-03-08
}}</ref>{{efn-ua|name=gallaghercorp-rebound-is-not-hardness|1=See table in the Gallagher article showing polyurethane compounds with varying hardness from 60A to 95A and varying rebound values (Bayshore Resilience) from 25% to 60%, with no correlations. A [https://www.youtube.com/watch?v=mjV1l7kt2JI YouTube video] ([https://web.archive.org/web/20250224181501/https://www.youtube.com/watch?v=mjV1l7kt2JI archived]) from the article demonstrates "polyurethane resilience" tests (yet another name for Bayshore Resilience) showing two balls with the same hardness, but opposite rebound values. At 0:41, an inline skate wheel with high rebound was shown bouncing off the floor.<ref name="gallaghercorp-polyurethane-resilience-elasticity-rebound"/>}}<ref name="powell-svensson-inline-skating"/>{{rp|24–26}}