If you opt for a “trim to fit” skin system, dialing in the width and length can help you gain sufficient grip while maximizing glide and minimizing weight.
Sizing Skins
Let’s try to keep this simple. There are a few things to consider when sizing a skin. The two main dimensions to consider are length and width. Of course, you could go the easy route, which many folks do, and purchase pre-cut skins for your ski.
That strategy isn’t so handy when, for example, you prefer a specific skin brand/model that doesn’t come pre-cut. You can build a skin from scratch by purchasing a length of skin off the roll and the appropriate tip/tail attachment system. We do this regularly for skimo race skins or efficiency mods. Last season, we highlighted Ski Trab’s tip hardware—it’s a sweet upgrade for those seeking a ski-mo-inspired tip-rip system for their larger skins/skis.
However, if we’re not opting for a pre-cut skin, we often choose skins in the “trim to fit” category. This means the skin comes in a fixed length. Still, we can adjust the tail attachment to be shorter or longer to dial in the fit. The “trim to fit” applies because you’ll be trimming excess skin material down the length of the ski to accommodate the ski’s varying widths.
Skin Width
When the skin arrives, you’ll likely see the skin material extend beyond the ski edges. (The skin is wider than your ski, particularly underfoot. Your job is to trim each side along the ski edge and expose the edge. How wide should you order your “trim to fit” skin? We’re here to help with that question.
Many of us use the Pomoca FreePro 2.0 skin. It comes in two widths, 140mm and 123mm. Let’s take an Atomic Backland 107’s specs, 137mm-107mm-124mm [182cm length]. This is not the widest of skis; it’s also not skinny. Further, the rocker is ample in the tip but not too aggressive. The thing to consider is that modern rockered tips and tails don’t offer much grip while skinning. Therefore, having the skin material cover the tip zone/ski shovel edge to edge is not critical. If more than a few millimeters of the base is exposed in the tip/shovel zone (from edge to edge), that’s OK. Be more concerned about ample skin coverage underfoot and the 15cm fore and aft of the binding mount zone. We’d opt for the 123mm width “trim to fit” kit in the case of Backland 107. (The 123mm width is a match for the tail, which gives you an indication that you’ll get plenty of coverage where it counts.) If the ski were wider underfoot and in the shovel, we’d likely opt for the 140mm width kit.
Skin Length
Let’s continue to use Pomoca’s sizing model as a base.
XL: 185 – 200cm
L: 175 – 190cm
M: 165 – 180cm
S: 155 – 170cm
XS: 145 – 160cm
It is nice to have some latitude to dial in the fit. This means that if you are in a 175-177cm length ski and opt for the large skin, you’ll likely be cutting the excess tail off (the rubber part of the tail attachment kit). Further, the skin/plush will run nearly to the end of the ski’s tail. The truth is that extending the skin to the tail endpoint is unnecessary. Even if you have 10-20cm of exposed base in the tail section and the skin is otherwise cut properly, your grip should be sufficient.
In this case, the medium-sized skin would suffice with a 175cm-177cm length ski.
The Skin Size Ethos
There’s a theme here. We are keen on excellent grip—meaning the skin runs near edge to edge where it counts, which is underfoot—and keeping excess skin to a minimum.
It’s OK not to have the skin cover the entire ski base near the rockered portion of the tip and tail. A lack of skin coverage shouldn’t be an issue, even with a more traditional un-rockered tail. Less skin coverage, in this case, helps keep skin weight and wasted skin material (the plush you are trimming off) to a minimum. The exposed ski base in the tip and tail will also improve glide. This approach may save you a few dollars, as wider and longer “trim to fit” skins are generally slightly more expensive. If you are a fully rockered ski enthusiast, 4FRNT Hoji fans out there, their pre-cut skins are 123mm at their widest—and some complain of front end slippage while skinning. You may want more grip in some form. Perhaps this means a size wider or longer for a bit of extra coverage
I curious as to your opinions/experience on ski/skin width vs. length on grip. I was killing time in a ski shop listening to an employee tell a customer that the Bentchetler 120 with significant tip and tail rocker wasn’t good on the skin track because of the lack of contact at the ends. I’m thinking, I’ve skinned up a lot of tracks on this exact ski, in a variety of conditions, and my feeling is the extra width under foot where your actual weight is seems to more than make up for anything at the ends with no weight on it anyway.
I think you are spot on. Coverage underfoot is key. A lack of coverage moving toward the tip (as in maybe this was a poorly cut skin) can also cause some skinning issues. Categorically claiming a ski is poor on the skintrack maybe doesn’t consider that it could be the skin (not enough coverage where it counts) and, perhaps, the skinning technique when the track kicks up a bit, could use some fine tuning. It is likely not a ski issue—especially since it sounds like you’ve had positive experiences with the Bent 120. I’d like to try these skis on a deep day.
Yeah, they’re great on deep days. But I think the Bent 120 is underappreciated for its meadow skipping abilities. Doesn’t really lend itself to compelling marketing though. “High avy danger? New snow and sketchy snowpack? Are you experiencing that internal conflict between seeing your social media feed full of people going big and still going home, but you just don’t feel comfortable taking that much risk? Maybe low angle pow is for you, and the Bent 120 is the category-leading contender. You’ll make no compromises as you maintain decent speed down 25 degree slopes, flying past your friends on their puny all mountain skis. Early season shallow snowpack? Bottomless facets? The Bent 120 keeps you off the ground, and the rockered twin tips allow easy slarving between and through forests of aspen shoots and last season’s wildflower stems. Let’s be real, you’re more likely to skin a couple of 700 foot, low angle pow laps than drop 50 degree pillow lines in BC. But either way, the Bent 120 is the cool kid ski for you.”