There is not a straight forward answer to whether or not you can take the fork off your mountain bike (MTB) and put it on your skibike, or simply swap the existing fork out with something else.  Regardless of what you are wanting to do, there are several factors that need to be addressed:

  1.  The biggest factor is steer tube length.  We cut our steer tubes considerably longer than that of your average MTB for two reasons:  A) the head tube on our bikes are longer than on most MTB, and B) we like to leave an average of 2-2.5″ (50-63mm) so that you can fine tune the height of the handlebar with spacers.  The cut length of our steer tubes will vary depending on the size and model of frame, the headset being used and the type of handlebar being used.  For example, a medium Recon with a Cane Creek headset and BMX handlebar will be cut to roughly 8.75″ long whereas a large Launch with a Zitto headset and DJ handlebar will be roughly 9.75″ long.  The shortest allowable steer tube length for a medium Recon would be 8″, which would allow for a single 5mm (just under 1/4″) spacer above and a single 5mm spacer below the steer tube.
  2. Wheel size is the next factor.  The wheel size MUST be 27.5″.  Our bikes are designed to work with only 27.5″ and anything else will throw off the geometry.
  3. Travel.  Each of our models is designed to work with a range of travel and, like the wheel size, anything outside of that travel range will throw off the geometry.  The Recon range is 150-180mm; the Launch range is 150-203mm; the Sortie range is 150-160mm.
  4. Axle size.  You need to make sure that the axle size of the fork you want to use is the same as the one you are currently using.  Why is this important?  The axle caps on the knucklehead (the big block looking thing that attaches the fork to the adapter/ski) is specific for the fork currently on your bike.  For example, if your current fork has a 15 x 110 axle and the fork you want to use has a 20 x 110 axle, you will need to purchase and swap out the axle caps.
  5. Lower leg diameter.  This only applies if you have the new front retention system; if you have the old bungee strap style you can disregard this section.  If you look at the lower legs of your fork, you will notice there is a metal clamp (band) that goes around it with a black pad that sits between the band and the leg.  There are four combinations of clamp and pad size.  For example, if the current fork is a Marzocchi Bomber Z2 and you want to upgrade to a Fox 36, you will need to purchase a different size clamp.  If you have the Z2 and upgrade to a Fox 38, you will need both a new clamp and pad.