When plowing last weekend with my model R I was in 2nd gear pulling 4-16s I had zero slippage. Are you suppose to have some slippage? My front tires came off the ground a few times only a inch or so but no spin thanks.Most of the comments indicate you do want some slippage. I would have never guessed that. Actual numbers offered by the comments vary between 5-8%. One comment pointed out that if you are slipping, you know all of your horsepower is going to the ground. As long as it is moderate, you are productive.