It depends a lot on the snow's condition. They can be a lot of drag especially in wet snow but then you can add on the plaque under the tires. They are model 4000 and they are approved to fit Cessna 185 so they float a lot.
The last time I talked to Mr Richard J. Schneider, Aviation Development Ltd, 740-437-7688, Hillsbury, Ohio, was about 3 years ago. He was thinking of building more skis but you can find them used. STC SA1912NM and SA728AL. You need tires from 8.5 inches to 29 inches.
When I bought mine my vendor told me, and it is written on the skis, that their weight was 38 lbs each but in fact they weight 61 lbs each and this is without the bottom plaque! My skis have teflon under. I don't think that this is standard. The teflon is attached to the ski with a steel skid and this skid touches the ground when there is holes. This is a problem on gravel and grass. You can be stuck if the hole is big anough and there is no snow under the ski. So 8.5 inches tires is a minimum and you don't want soft tires. The teflon and the skid are maybe the explanation for the difference from 38 to 61 lbs. They are very good for my type of operation. Good luck.
