For its new 2010 freeride skates, the NRK and the NRK Road, Fila reused a whole bunch of features from existing skates, but introduced one never seen before on freeride skates : Low Profile frames which fit 80mm wheels but have a height of 35mm vs. the usual 40mm. This is a feature Fila is very proud of having patented with the 195mm mount spacing of speed skates.
Low Profile frames have the advantage of lowering the gravity centre of the skates, improving balance when tilting the skates sideways. But for 165mm mount spacing, they also have the disadvantage of not fitting on most skates. Not without modifications to the shells. And longer frames to fit larger wheels like 84mm or 90mm won’t be possible to produce as Low Profile with the 165mm mount spacing, since the front mounting bolt would be in the way of the second wheel.
The 165mm mount spacing of these frames is the most commonly used on non-speed and non-aggressive skates (where the most common are 195mm mount spacing and UFS respectively), but their Low Profile means that the second wheel requires a 5mm space above it, which very few skate shells provide so close to the mounting bolt.
These pictures show a modified 2004 Rollerblade Twister Plus, where the shell’s plastic has been cut out where required to make space for the second wheel. Other skates can be modified in the same way, though some will be hard to modify, such as the Seba skates with aluminium mounting plates in the shell.
As of mid-2010, these frames aren’t available separately. You can find full details about these frames on Wikinline.