Ski Builders Forum

i am making my first pair of skis. they are to be 180cm long and have the dimensions of 130-100-120. now 100 is the waist width, just where do i put it on the ski, Ex. 100 cm from tip. please give me your input.

I snowboard.....but you should definatly figure out what a ski is before you attempt to make one. The waist width is skinniest part of the ski and depending on your personal preference, located at or around the planned boot center.

sidecut radius will determine

General consensus is to work out the running length (amount in contact with the snow) and place the waist at 55% of the running length from the tip.
Eg. For a 180cm twin tip the tip and tail will be 15cm long each. So the running length will be 150cm. 55% of that is 82.5cm. So waist should be 82.5cm from the start of the running length (or 97.5 from the ski tip). Boot centre is usually placed at the waist point also.

Download Sno-CadX, it will figure out where the waist goes for you, then if you want to move it you can do that also.

I like to have the ball of foot (BOF) over the center of the running length. For this reason I tend to use a 50mm setback for boot center, regardless of ski length. But like everyone else has said...it comes down to personal preference and other ski geometry.

If you're doing a circular sidecut, you can't move the waist given some pre-determined width dimensions. They define where the waist will be, its just geometry. If you want to move the waist fore/aft, you have to change either the tip or tail width. If you make the tail narrower, it moves the waist back for instance.

Dtrain wrote:I snowboard.....but you should definatly figure out what a ski is before you attempt to make one. The waist width is skinniest part of the ski and depending on your personal preference, located at or around the planned boot center.

you are a retard, you obviously dont know what point i am trying to make.

hum.. this is your 2nd message rybutler... a "thanks for those helpful replies" would have been a better start to show some respect for the guy who gave you an actual answer !
Even though DTrain's reply was a bit rude, we see so many people not reading the posts and directly asking stupid question that I cannot blame him. If you think people are gonna help you again with this attitude I think you're wrong !

Anywhere between 2 to 5 cm back from true center, so in your case 92-95 cm back from the tip. Read more, as in everything on this forum, post less.

rybutler wrote: you are a retard, you obviously dont know what point i am trying to make.

The fact that you asked the question tells me that you dont have a good grasp on building skis/boards. Name calling wont get you anywhere.

Ok, lets start over....

Are you saying that you want to make an assymetric ski and thats why you ask this question?

rybutler wrote:

Dtrain wrote:I snowboard.....but you should definatly figure out what a ski is before you attempt to make one. The waist width is skinniest part of the ski and depending on your personal preference, located at or around the planned boot center.

you are a retard, you obviously dont know what point i am trying to make.

I do know what point you are making! I too have asked a couple of these gentlmen to hold my hand and guide me though my ignorant or brain dead building thoughts, and I read these forums/journals for almost a year before i even asked a question.

But even this retarted knuckle draggin' snowboarder knows where he would want his waist width on ski. Any where I preffered it. If you dont even have a thought or prefferance to the easiest of design specs, you should not even be reading this stuff. You belong at a mainstream sports outlet getting advice on what to buy, not what to build. My answer to your question was blunt but true. And If you were trying to make a point with that question, I dont think anyone got it. I can already see your next question....."where do I want me boot center?".

so ya.........actully didnt get the point.unless it was that you dont know a thing about skis!

Twizz is right. If you have a predetermined tip and tail width and you put your predetermined "waist" in a certain spot it won't actually be the real waist (narrowest point of the ski). I did this on the first few designs before realising that the real waist was behind the place where I thought I had put it.
My latest design I chose a running length and a sidecut and placed the apex of the circle at my waist point. This waist point and sidecut then defined the tip and tail widths.
You realise after a while that all the parameters are linked and the physical realities of geometry mean you can't define all the parameters independently.