Materials / Fit
ZipFit has gone through a few different design iterations over the last few decades, from gel to foam to cork. The current cork design used in all models is a patented mold of a compound called OneMinuteFit (OMFit), a mixture of granulated cork and a ceramic binding adhesive. The compound is fluid at room temperature, but still stiff enough to give you excellent hold and responsiveness in the boot. The compound will mold over time as your boot or foot changes, resulting in a permanent, comfortable, high-performance fit.
The OMFit actually expands slightly (10%) when heated compared to normal cork or foam injections. This in turn provides you with a very tight fit while skiing. This also results in a liner that never “packs out.” People are rumored to have skied 800-1,000 days on one set of liners with no problems. Racers typically go through two or three shells before the liners wear out.
The claim by ZipFit is as follows: “The OMFit is the most resilient, supportive, protective, shock absorbing, heat exchange and insulative material ever devised for boots.” And although I can only compare to my collection of stock liners, I can’t argue with any of these claims at this point.
Initial Fitting / Break-In Process
The initial fitting of the ZipFits was very simple. At The Boot Doctors, we heated up the liner and shell. I put the liner on my foot, slipped into the shell, buckled the boot to medium tightness, and walked out the door to go ski. The liners have the option of injecting additional cork if needed after the initial fit, but my last time in the shop was when I walked out after heating—they fit that good from day one.
That being said, ZipFit claims the liner takes a few days to break in, so expect a very (emphasis on very) tight fit for a day or two. This was true with my experience. My first two days were basically: ski a run, head into the lodge to get out of my boots as quickly as possible, let my feet breathe, repeat.
But following these two break-in days, I have yet to take these boots off again while skiing. And the performance, as mentioned, has greatly improved over my stock liners. I believe this is for two specific reasons:
Precision Fit, Increased Performance
First, the plastic molded asymmetrical tongue with the same OMFit cork as the heel pockets. The fit and responsiveness of this tongue was much improved over the stock Lange liner, with consistent contact from top to bottom on my shin. The ability to drive the liner into the boot shell and get everything that shell was designed for both back into your leg and into the ski is what a liner is designed to do. And the ZipFit does.
Second, the tight fit from heel all the way up to the top of the calf allows full transfer of any movement directly into the boot shell, therefore giving you the instant ability to move the ski how you’d like. Whether it is driving the tip with the fore-aft movement of the shell or the angulation to the side, the initiation is instantaneous and precise when needed. There is no lag or movement, it is quick and precise.
Even four months later, I was still amazed at how tight these are everywhere. Not just no heel movement, or good fit around the calf, or a good toe box—the ZipFits improved the fit from the toe to the top of the calf and everywhere in between. And this is how you end up with a very high-performing liner.