Types of Ski Boot Liners
Custom ski boot liners are bought separately from the shell and customised to your foot and biomechanical requirements. Most ski boots come with an off-the-shelf liner. Sometimes they look fluffy and plush and feel nice, but the foam within them is mostly un-mouldable, does not have memory, and will pack out reasonably fast, causing discomfort and fit issues. There are a few types of ski boot liner replacement options:
Above is a cross-section of an off the shelf liner. Note the multiple layers of different foams - none of which are memory foam. They feel soft and cushy initially, but then perish and pack out fast. Off the-shelf-liners last about 5 years (due to foam breaking down from time) or 200 ski days (when they pack out).
Foam Injected Liners
A foam-injected liner is the way to go for ultimate fit and performance. Your boot fitter will select the most appropriate structural shell for you, considering any modifications your foot type may need, and then foam you while standing in the liner and shell. The foam enters the liner and fills in all the gaps and contours of your foot, making for a custom fit. This gives you the best performance because every movement you make will translate better to the ski for control and edging.
Benefits:
Ultimate control and performance.
True custom fit.
Best way to accommodate volume differences between the lower leg and foot.
Great for people with very bony feet or orthopaedic hardware (previously broken bones that have been pinned).
It will last double the lifespan of an off-the-shelf liner that normally comes with the boot, so it is worth the investment.
Lasts 400 to 500 ski days.
Considerations
Need to be foamed by an experienced boot tech: These can go awry very quickly unless done with expertise. Incorrectly foamed liners have given foam injection a bad name.
It cannot be moved from boot to boot.
It can be too precise for people wanting to walk a lot (such as ski patrollers and ski tourers).
Intuition Liners
Intuition heat mouldable liners are made from a fancy foam called Intuition foam that is completely heat mouldable to your foot.
Benefits:
Easy to remould.
Can move from boot to boot (however, does your boot shell need updating too? Is the plastic breaking down?).
They are warmer because they trap more air in the foam.
Not as restrictive in the foot moulding, so good for touring boots when doing some walking.
Mould and retain shape from memory foam.
Lasts 300 to 350 ski days.
Considerations
Intuition liners mould around your foot, and the memory foam holds that shape. However, the moulding process compresses foam and starts the wearing-out process, so they will not last as long as foam injected (but still much longer than off-the-shelf liners). They do not have a lot of foam to fill large gaps in the boots (like narrow ankles), so they can still require aftermarket padding.
Cork Liners
Also known as SvenFit or ZipFit, this comprises a self-moulding cork-composite material that continuously adjusts between the feet and the shell. The cork material is around the lower ankle and goes through to the midfoot. The forefoot and toes are neoprene, which can be chilly in very cold climates, however they now have lambswool lining here which has reduced the cold issues.
Benefits
Firm hold: Not foam, so they do not pack out like other ski boot liners.
Remouldable in different boots.
It does not ever completely set, so the liner always maintains some degree of malleability. This is great for touring or standing around in your boots (like a ski patroller or ski instructor).
Easy to mould and fit.
Considerations
Since they are a fixed volume, they often need aftermarket padding to correct the volume.
Being malleable, they will move a bit and not give the performance of a foam-injected liner.
They can be tricky to put on: Most people put the liner on their foot first, then slide into the shell (a race entry). You get used to it, but it will wear out the liner's seams much faster, and it will fall apart sooner than the advertised lifetime of the liner (about 400 to 500 ski days).
So, there you go. All custom liners last much longer than off-the-shelf liners, which pack out and wear out faster. All custom liners give a superior fit to off-the-shelf liners. You need to consider what you want from your liner, namely performance versus comfort, as there is almost always a compromise towards one or the other. Come in and chat, or just drop us an email about what you want from your skiing, your boots, and what works best for you.