The base and edge bevels work together to make the ski easier or harder to turn, more or less grabbier etc.
There's two types of angles: the base edge angle (0 is flat with the ski base) and the side edge angle (90 would be 0, so 87 would be 3, depending on how you look at it).
Generally, the base angle determines how quickly the ski grips and the side angle how strong it holds. They dictate how hard the ski grips and bends. So there's also some athleticism involved in deciding.
Also the type of ski. Fat skis flex laterally enough to cancel say a 3 and are not meant for hard turns on the ice. So it's more customary to have a 1/2 on them say at 85 and up or such, although I do have 95s set at 1/3, so it depends also on what type of snow you use them on.
Also the radius and usage: if you put a 0.5 and 4 on a speed ski, you're looking for trouble as it may grip unexpectedly at speed and either causes a high side or tear the knees off
As a recreational skier, I used to use 1 degree base and 2 degrees on the side, for all my skis, including slalom, GS, fun skis, kids skis etc. This keeps things simple. As I started skiing harder and better, I moved all my skis to a 3 degree side bevel, still with a 1 degree base - I started noticing the difference: a better hold while carving on hard snow, while still forgiving. My skis are now at 0.5 degree base and 3 edge and they carve stronger.
As a rule of thumb, you can't go wrong with 1 degree base and 3 degrees side.
These are just rules of thumb, use them as such. You should adjust based on the racer's technical mastery, strength etc.
For up to U12, kids should have 1 degree base and 2 degrees side bevels.
For strong U12 and U14, they can go to 1 base and 3 side.
For strong U14 and U16 and higher, they can go to 0.5 base and 3 side for SL. GS skis can stay at 1 degree base and perhaps go down to 0.75 or even 0.5, if you feel it's needed. Strong racers U16 and up can go down to 0.5 on the GS skis as well.
As they progress through the ranks and you want to spend the big time or bucks, you can move to progressive base bevels, (as high as 1 degree at the tip, down to 0.5 or to 0 underfoot), for SL and GS, as the racers grow stronger.
The 0.5 base bevel underfoot requires strength and technique, because it provides quite a lot more grip and it's more common at the higher levels. As far as edge bevels go, 4 degrees is not uncommon for racing on ice, for strong racers and could go even higher in some conditions.
Speed skis (SG and DH) are different... If you have them, keep them at 1 degree base and 3 side and move to progressive base bevels when warranted. It actually is a safety issue here, so be sure to talk to a coach: a too sharp base bevel makes the skis too grabby at speed.
Read more about how bevels influence skiing: Ski feedback.
You should keep things simple. A quarter of a degree won't make a huge difference and not having to choose between many bevel guides and options, simply reduces the costly mistakes and keeps the daily routine to a minimum. Those angles are good enough for performance skiing and race training - they grip enough even for racing at these levels and stay sharp long enough to allow me some free nights (1 base/3 side and 0.5 base/3 side).
So - get an adjustable base bevel guide and a fixed side guide. Why adjustable base guide? Park skis need more than 1 degree there - that's the only reason why I bothered with an adjustable base bevel. I have a range of fixed base bevels, which I now only use for diamond polishing and deburring.
As you ski and tune more and more throughout a season, the base bevels start to increase, so if you started with a 1 degree, you may end the season with 1.5 - this is also the reason you should start the season with a base grind and reset those angles.
This is also why you should start small and put some thinking into this - the only way to get the base bevels lower is to grind the base. At the same time, for younger racers, 1 degree base bevel is good and you don't need it higher than that.
I do not file the base edge anymore. I only use a fine 400 diamond file, lightly, in a guide, for deburring, when I file the side edge. The more you file or use a diamond on it, the faster the bevel grows and the sooner you'll need a base grind.
A higher base bevel (1 degree) will make it easier to pivot the ski. Also, it is less grabby, so, for beginners, it is better to use 1 degree for the base bevel. You sacrifice some edge hold for ease of use.
A smaller base bevel (0 at the extreme) provides better edge grip (at the same side edge angles) but it is quite a lot harder to use - this is suitable for experts: if the skis "hook up" on turns, increase the bevel by a half of a degree.
Variable base bevels offer some level of forgiveness (1 at the tip) combined with good edge hold once on edge (0.5 underfoot), but are more work to maintain.
Read more about how bevels influence skiing: Ski feedback.
Remember that it is hard to lower the base bevels for a ski - as the kids grow, it takes a base grind to get them on lower bevels.
You can adjust the bite at the outermost points of the tip & tail by increasing the base edge angle....which yields a less aggressively biting edge in that zone, yet still allows you to easily tune the side edge sharp from widest point to widest point. most European techs I know prefer to vary the degree, using more base bevel at the tip (10-15 cms) and tail (5-10cms), with a consistent bevel in the middle 80% of the ski. The difference? Subtle. All things being equal (and they never are…), the ski with the same base bevel along its length will hookup more quickly a the start of the turn as the ski is tipped on its side, engaging the complete shape all at once. The ski with slightly more base bevel at the tip and tail (side bevel is always the same) will engage the entire shape more progressively.
Read on for even more Ski Tuning Ideas.
If an athlete doesn't know what edge bevels to ask for, always ask for the factory edge bevels that came on the ski.Ski Racing mag 2009