Help me understand front ski pressure & shimming

[DJ Tomás]

New snowbiker here on a Beta 500 RR-S with TS ARO3 S Pro fixed strut and Trio S up front. I've seen lots of comments about ski pressure, but don't have any experience to know the difference. My first ride was yesterday on whooped out trails to the powder in the mountains. I had a great time! How will I know if my ski pressure is good or bad, or needs changing? I'm guessing that too much ski pressure causes heavy steering and over steering? Too light equals not being able to turn? I'm more concerned about not getting stuck or trenching. If I were to put my bike on a scale and weigh the front ski and weigh the track, what percentage should be on each (knowing I'm carrying fuel and gear on the tunnel)? Also, what are the benefits to shimming and what tells me I should shim the front ski to bring the nose up? TIA.

 

[eric82930]

Too much ski pressure really wears your arms out especially in Spring snow and sometimes you'll get stuck easier because you can't even get the bike to move an inch to crawl out of a hole or wheelie over a log. you might even get stuck in the parking lot on ice. Not enough ski pressure will cause the ski to wash out in a corner.
Don't try to shim the ski until after you're happy with the ski pressure. Then you want to just make sure the back of the carbide is touching when you're sitting on the garage floor. If the front of the carbide droops down too much it will Dart around on the road. If you think you have too much ski pressure, the easiest thing to do is shorten the strut or Slide the forks up in the clamps. Putting stiffer fork Springs in with no other changes adds ski pressure but keeps the front from diving and having the front endo feel. If you do install stiffer Springs I would always readjust the forks in the clamps or shorten the strut if you can so the static ski pressure isn't too much.

If you don't have adjustable strut, Adjusting your front and rear track springs can help ski pressure problems as well. any increase spring in the front track takes weight off the ski. And a decrease in the rear spring also takes weight off the ski because it let's more weight be carried on the front track spring.

I usually set up my bike so that front track paddles touch the floor before the back paddles when I left it from the rear bumper.

 

[sledsuperman]

I believe that there is not enough emphasis put on the effect a suspension strut has on ski pressure. Even with the a fixed strut adjusted correctly the ski pressure is much more noticeable than a setup with the suspension strut. Having that extra pivot point makes a large difference and ski pressure becomes much more manageable.