Shimming Skis, How much is too Much

[grizztracks]

Have you checked the ski rubber to make sure the thicker portion is in the rear? I've seen new sleds come with them in backwards.

Here are some basic adjustments to reduce darting: http://cs.amsnow.com/sno/b/sno/archive/2013/11/15/snowmobile-darting-around-issues-help.aspx

 

[provfisherman]

Yep checked the rubbers and the thick part is in the rear. That article that you reference is one of the articles I read that lead me down this path. I started this whole thing by researching this darting cornering thing and came across many articles that talked about adjustments and shimming and here we are. The reality is that I am perfectly willing to spend the money to get snow trackers and even different skis if required, I just want to exhaust all the other issues first and see if that can get me to a place that I am comfortable with before doing that. Besides, doing these things helps me learn about how all these adjustments work and what can be done to improve the sleds with them. I just need some help and nothing is better then advice from experienced people. Printed articles only help so much.

 

[grizztracks]

I'm actually running shimmed ski rubbers on my 2015 Viper that's running Curve skis. When I purchased the Viper I ran the Tuners for half the season then replaced them with Curves due to unpredictable handling and poor flotation in deeper snow. To install Curves you need their mounting kit which includes ski rubbers but their first version of skis rubbers for the Viper didn't lift the front of the ski enough which caused darting so I shimmed them with 3/16" aluminum plate to correct the issue. The following year I was talking to the guys at Curve and discovered they were aware of the issue and redesigned the rubbers so shims aren't needed. They sent me out a revised set that are thicker in the rear but I havn't installed them yet because at this point I have no darting with the skis shimmed.

 

[provfisherman]

Well sounds like you have your handling under control. I am not ready to abandon the Tuners just yet because I did not have the same issues with the Phazer, just the MP. The Phazer darts a little but I can live with that but the MP darts a lot more and pushes through corners which I am hoping is just the difference between the longer track and wrong adjustments. From the description you have about your shimming, it sounds like regardless of how much shimming I have under my rubbers, I will have to put a few miles under her before I make any judgment. Just worried I will not know if I have too much shim. If there is too much shim, will I know it based on the handling? Are there any ill effects because of too much shimming? You know weird things like that. Might be worried for nothing, hope so.

 

[grizztracks]

To much shim would result in excessive rear carbide wear and less responsive steering. The idea is to get the tips of the skis up just enough so they don't have a tendency to follow routs. I lift the skis slightly off the floor to check the ski rubber setup. The front of the ski should be slightly higher than the rear and if not I add an appropriate shim to get the tips up . I've found that a 3/16" aluminum plate is usually enough. The push that you experience is partial due to the dual keel design. Snow is forced between the keels and compacted to the point that the skis start to lift resulting in lost bite. Single keel skis allow for the snow to push out the sides instead of being trapped between two keels.

 

[steiner]

Like many people here I have tried all sorts of carbide setups,shim tricks and skis. All made a difference. Some more than others.
I have found that the ST's the best solution with the least amount of modding. Fixes darting and the push in the corners.
Daulies fix the darting issues but push too much for me. Triple points worked well but you need to use the ski saver and shim to overcome the darting. The plus with the TP's is that they turn well on pavement even with a longer track.
Have tried some after market skis as well. They do seem to fix the darting and do handle decent on the trail. Just found the better they "bite" the heavier the steering. Very tiring after a 300 mile day.
My MTX skis with the ST's have been the combo for me. Decent flotation, good keel depth for the lose snow and the ST bite well, eliminate darting and make the steering feel light.
Have not tried Tuners as of yet but with ST's record on single keel skis I'm sure they will perform as advertised

 

[provfisherman]

Well with all the good information that I have gotten here, it appears that there is not much I can do until I get the sled out on the snow to test the latest adjustments including the shimming. Hopefully I will have some better answers to this problem after some miles have been accumulated. With any luck I can solve this to my satisfaction with some more fine tuning. If not I guess it will be decision time on which of the good options suggested to go with. Thanks to all for the assistance. Good ole process of elimination here we come.