Can I adjust length and Z-value of ski bindings myself?
A correctly adjusted ski binding keeps your boot firmly on the ski and automatically triggers the release of the boot due to a certain force. The binding therefore is a safety factor that should not be underestimated. The Z-value tells you how to (let an expert) adjust it. This in turn depends on the ski boot, skiing ability, your body weight and other factors. But for now let's start from scratch!
Should I adjust the binding myself or have it adjusted?
The ski binding is a curious thing: Yes, you can adjust it yourself and, in addition to your Z-value, all you need is a fitting screwdriver. Caution: You should only dare to adjust the binding if you already got some skiing experience.
If you are an absolute beginner, it is better to have the ski binding adjusted by a dealer or specialist. For professional adjustment, a standardised testing device for ski bindings will be used for testing when the binding triggers. You will also receive a bfu ski vignette, which you can use as a proof to your insurance company after an accident happened.
What is Z?
Z indicates the force at which a ski binding automatically releases the boot. For example, if you fall and your ski detaches from the boot in time, the risk of injury by a twisted ski will decrease considerably. At the same time, of course, your boot must not be too loosely clamped, as this can cause you to lose your ski in a sharp turn - which poses the risk on the other end of the spectrum.
The bottom line is that a higher Z-value will need a higher force for the binding to release your boot. This value has to be exactly adjusted to your needs, based on the following factors:
- Body size
- Sole length of your ski boots
- Experience level (subdivision into beginners, advanced and experts)
In addition to the Z-value method, there is another technique: Particularly in used as an alternative in Germany, which is called the tibia method. This involves measuring how wide your tibial plateau is. This effort can be eliminated by simply using the Z-value.
Sole length, contact pressure, ski boot size, weight: basics for the start
No matter whether you adjust the ski binding yourself or have it done in the shop: You should understand a few essentials about it:
- The sole length is a three-digit millimetre figure. You can find it on the outside of the ski boot in the heel area or determine it yourself by measuring from the tip of the boot to the end of the heel. Attention: Sole length and ski boot size are not necessary the same!
- The contact pressure refers to the pressure from behind (the heel mechanism) pressing the boot towards the front into the binding (front jaws).
- The body weight has an influence on the pressure and load on your skis. For example, it is unreasonable to use the binding with exactly the same Z-value for a very lightweight, small person as for a tall and heavy one.
- The experience level depends on your skiing speed and on which slope you are skiing.
How to know what level you're at? You can get oriented by by this classification:
- As a beginner you ski slowly to medium fast on rather flat slopes.
- Advanced skiers ski medium to fast on medium flat or steep slopes.
- Experts ski very fast and aggressive, especially on steep slopes.
Next, we turn to the question of frequency: When and how often do you actually have to adjust a ski binding?
Do I only adjust the ski binding for new boots?
It goes without saying, but for the sake of completeness it should be mentioned that with new ski boots the binding always has to be readjusted. This also applies if you have bought the same ski boot in a new design. A ski boot wears and tears over time, so that the old binding setting no longer works best. The binding is adjusted best if the boot does not slip and clipping the boot in does not turn into an act of ultimate force.
How often do I need to adjust the ski binding?
For new ski boots you need to adjust the ski binding, that much is clear. You have had your boots for a long time but you are sure that everything is still fine? Play it safe and let a professional check the binding once a year!
After all, it is possible that your weight has changed, your skiing abilities have improved considerably, etc. These factors can increase your Z-value - and thus making it time for a new adjustment. Speaking of the Z-value: How can you figure it out?
Table for Z-values: How to calculate Z for the bindings
The good old Z-value table: It is the established tool for all who wish to adjust their bindings themselves. Maybe you've already found out that you can calculate this value - but don't worry, there are no long formulas to remember!
Is it even possible to calculate the Z-value oneself?
You can use various calculators on the Internet and perhaps end up with different values, causing you to trust none of those numbers. Or...you can simply use the Z-value table for orientation without having to calculate anything! The values here correspond to the DIN standard 11088 and were determined on the basis of empirical data from ski accidents.
Z-value table for adjusting the ski binding
|Weight (Kg)||Size (cm)||Ski boot sole length (in mm)|
|Bis 250||251-270||271-290||291-310||311-330||Above 330|
|Z-value according to ISO 11088|
Quite a few numbers at one glance? Yes, but the table is still not difficult to read. Let's assume, for example, that a female skier meets the following criteria:
- 50 kg body weight
- 152 cm body size
- 291 mm sole length
With this information, the Z value is 3.50 - at least this is the initial value we got. Now the question arises of how proficient she is on her skis:
- Beginner: The base value remains at 3.50.
- Advanced: We go one line below the base value so our new Z would be 4.50.
- Expert: We go two lines below the base value and get to 5.50.
Caution: Age also sometimes requires further corrections. For children under 10 years and adults above the age of 50, the value must be corrected upwards by one line. Therefore, if our driver from the example above is 52 years old and advanced, we would be back to the initial value of 3.50.
If you now know your Z-value and are itching to adjust the binding yourself, you can use a screwdriver at the back of the binding. Be sure to check thoroughly whether the boot gets tucked tightly into the binding but is not clamped too tight. If that doesn’t work out and you have no idea as to why, ask an expert - just to be on the safe side.
As you can see, adjusting a ski binding correctly is no rocket science, and the Z-value not a mysterious number that needs to be guessed. On the contrary - please DO NOT guess. After all, it's about your safety when skiing, and you only ensure that with a perfectly adjusted binding. Everything clear? Then have fun on the slopes!