iSkate125 - Third Generation Prototype

c P.J. Baum, September 8, 2003

Recently I reported on tests of my second generation 100-90-100-125mm inline skate. The result was a frame that was perfectly stable with a standard 6.5 inch mount spacing speed boot. Until January of 2004 90mm wheels are in rare supply so I ground down a couple of 100mm scooter wheels to 90mm for wheel # 2. Yak Research distributes two 125mm wheels -- red 78A hardness and blue 85A wheels. They are is stock in the US and available quickly and cheaply. They also supply 100mm wheels. The third generation skate is shown below: Each iSkate frame was machined from a solid block of alloy certified by the supplier to be stronger that 7075 aluminum. There are three cross-supports which are rather strong. The axle pads are machined and the axle holes are threaded for quick wheel change. The result is a 12.6" (front axle-to-rear axle) skate which is much stronger than the earlier prototypes, rolls even better because of the increased axle accuracy, and is easy to maintain. The height off the ground has beem held to 101mm at the rear mount for great stability with the older boots. The iSkate125 frame has been anodized in a blue color similar to the YAK hub color. And now on to bigger and even better....... ********************************************************************************* More 125mm Skate  Prototypes c P.J. Baum, April 1, 2003 As an update to the 100-90-100-125mm report above, 90mm wheels are now available from Revtek (Millennium Skates) and from Arco (Swatskates). Recently I tested a new prototype -- 110-90-110-125mm: And then I was able to fit the frame above also with wheels of diameters 100-84-107-125mm by turning down a 110mm wheel to 107mm.  This allowed me to get an accurate idea of the difference between two different "Hi-LO" ratios (125/110 and 125/100) using the same frame and boots but with just the wheels different.   The 110-90-110-125mm is a "stiffer" skate withe a higher end top speed but which needs significant force to get there.   The  100-84-107-125mm  turns more readily giving it a faster low end acceleration and a faster stroke rate so the required push force is a little lower.  So I call the 125/100 skates sprint skates and the 125/110 skate a marathon skate.  The 125/125 skate described elsewhere (125-100-100-125mm) is an even stiffer marathon skate. It is a little like a one-gear track bike compared to ordinary multi-gear bikes.   I called the skate concepts here   "Gradated Diameter Big Wheel" skates (U.S. PTO 60/551300 March 2004). And the current tests show the feasibility of "Convertible Big Wheel" skates which change from sprint skates to marathon skates with only a change of wheels.