The first inline skates made were introduced to the world by hockey players Scott and Brennan Olson from Minneapolis in the 1980's. The idea came when trying to find ways to practice hockey in the off-months of summer and lead to the creation of Rollerblade, Inc by Scott who still holds 16 patents on the design. But since the inception, how have inline skates made today innovated in production?
Components of Inline Skates
Modern skates are constructed of three manufactured parts: the boot shell, the truck and the wheels. As the name suggests, the boot shell houses the padding and is integral to the comfort of the skater. The truck works as a chassis to fuse the shell to the wheels and so requires a strong but light material. The wheels' durability is a massive factor in the speed of the skates; hard wheels maintain shape and therefore don't waste as much energy in movement as old, beaten up wheels.
What material is used is entirely dependent on what the skates are to be used for. For the purpose of this How It's Made, we'll be looking at Aggressive inline skates made today. Recreational skates tend to be of simpler design and based purely for comfort, however because aggressive inline is an extreme sport it's important that it provides protection for the user. Boot shells are either entirely hard boots or hard/soft boots for added comfort. It's really up to the skater to decide if they want to forsake protection for extra comfort, they may not need it. A hard boot typically begins as a polyurethane mould. The mould is designed by a team working off sketches to create a 3D CAD model, going through stages of prototypes before mass production. Manufacturers spend a great deal of focus on making sure the aesthetics are perfect as the target audience tend to be young adults. More often than not the boot shell mould is comprised of several pieces of PU, that when hardened and constructed allow for greater flexibility. As this is occurring, the liner is being hand made by stitching absorbent foam to leather in the exact shape of the inside of the boot. This layers another degree of protection along with adding to the comfort of the design.
Truck and the Soul Plate
Where the wheels are fixed is the truck or chassis. The hard plastic on the flat of the boot is the soul plate. One reason these are two separate components to the aggressive skate is because the truck's design incorporates the H-Block. The H-Block is the arched gap between the 2nd and 3rd wheel that allows for grinding. As it's a high impact zone on the skates it needs to be sturdy but replaceable for when it finally has taken too much of a beating without the owner having to replace the entire boot.
Thankfully, most modern skates have adopted the UFS (Universal Frame System) meaning that any brand chassis can connect with any other boot, passing the savings on to the skater. The creation of this chassis is a deceptively simple process that requires enormous force. An aluminium foil, to the manufacturer's specification of thickness, is placed into a pressing machine. The pressing machine then applies enough force to manipulate the shape of the foil into the frame. Once set this is anodized to resist corrosion and finally housed in a polyurethan case which would continue the aesthetic design of the boot.
For the entire process the wheels are the most fundamentally important and so, as expected, are treated with such reverence. The boot provides a service of protection, comfort and aesthetics but the wheels are really where it's at. Once a suitable design is in place a mould is created with an aluminium block. The block becomes a negative, rendered using an Electrical Discharge Machine (EDM) that forces through the metal and is capable of the most intricate designs however it takes around 40 hours for every 12mm carved.
As the mould is readying, the raw material for the core (polymers or fibreglass) is passed through a dryer to remove any moisture. This process is integral to the longevity of the wheels and is the last step before injection into the final shape. The mould is fixed to the injecting machine, which is heated to 230C and evenly distributed. The raw material is then injected through a tiny point under 2200 bars of pressure and held into place with a closing pressure of 50 tons. After setting the wheel cores are placed in casts, where the over-core of PU is poured in and sealed. In this tank the wheel takes on it's final shape. After only a few minutes the casts can come off, but the wheels are far from the necessary hardness. This is achieved through cooling for 24 hours and the placing in the oven for another 72 before a final cooling.
Lastly the custom designs are applied to the wheels via pad printing. Ink is added to finely engraved cliche plates and pressed to the wheel. Each cliche plate is so finely designed that only a single ink colour may be used, so multiple coloured designs require a plate for each colour. The wheels are fixed to the frame, the frame to the soul plate which is attached to the boot and that is a complete custom designed aggressive inline ready for packaging and delivery. Perhaps you may be interested in checking out our other blog posts like the health benefits of skateboarding or our article on triatholons vs. start ups.