Ready to kick off the ski season with a good ol’ ski tuning sesh? We like your enthusiasm. But before you go to town on edges that may be rusty or dull from last season or questionable summer storage: Please, for the love of Ullr, do not get file-happy on your skis’ base edges.
Skiers new to tuning their own skis—and even some experienced yet overly-enthusiastic home-tuners—make one critical mistake when picking up the file at home: They don’t differentiate between their skis’ side edges and base edges. They’ll take a file to each in an effort to get both sharp enough to cut through early-season boilerplate conditions. The problem is that taking a file to your base edges does more harm than good.
“When you mess with your base edge, you change its bevel, which influences the responsiveness—not the sharpness—of the edge,” explains Leif Sunde, ski technician and owner of the Denver Sports Lab in Golden, Colo. That, and your edge bevels likely aren’t the same.
Understanding the difference between edge sharpness versus responsiveness comes down to understanding edge angles, explains Sunde, and how a ski’s side edge bevel and base edge bevel combine to help your skis hold an edge in a carve. In short, it involves math. But because no one wants to do math when tuning skis, here’s your cheat sheet.
How to Calculate Ski Edge Angle
Skis have two types of edges: the side edge, and the base edge. Each has a different purpose, and is therefore beveled differently:
- Side edge bevel is indicative of the effectiveness of the edge, i.e., how far you can tip the edge into the turn before it loses its grip.
- Base edge bevel is indicative of the closeness of the point of your cutting edge to the snow. The greater the bevel, the farther the edge will have to travel to contact the snow. Base edge bevel dictates the responsiveness of the edge.
Together, the two make an acute angle and that is your ski’s edge angle. Here’s how to calculate your ski’s overall edge angle:
Edge Angle = (90 + Base Bevel) – Side Bevel
Most recreational skis are tuned in the factory to have a 2-degree side edge bevel, and a 1-degree base edge bevel, which means they feature an 89-degree edge. The smaller the angle, the sharper the edge, so race skis typically feature more pronounced edge bevels and a smaller edge angle.
Edge Maintenance Pro Tips
- Sharpening the side edge: Be sure to use a file guide that matches your ski’s side edge bevel (most likely 2 degrees, so use an 88-degree file guide).
- Don’t take a file to your base edge: Even if you use a file guide to touch up your base edge bevel, you take away edge material without removing base material. This results in a greater edge bevel than indicated on the file guide and your skis will become less responsive despite feeling “sharp.” A stone grind is the only thing that will fix this, and that means stripping away even more edge material, reducing the life of your skis.
- Less work, more often: Regularly take a diamond stone to your side and base edges to remove burrs; be sure to use a file guide.
- If something feels off: It’s time for a professional tune. If your edges feel dull to the touch, hooky, or unresponsive on snow, your edge bevels may need to be professionally reset.
Leif Sunde, owner of the Denver Sports Lab in Golden, Colo., is a highly experienced ski technician who founded the Denver Sports Lab to make Olympic-level tunes available to the public.