Covered our first North Trail for 3 winters with very little issues. It was nice and clean, with no black streaks, when we uncovered it for the start of the year. When we purchased the new North Trail 5er we debated covering it or not. We decided not to cover it and by the start of this year, it was so dirty, it took hours of scrubbing to get it clean. NOT again. It will be covered this winter.
We used the gray cover from ADCO. Camping World had a great sale with free shipping and then they added tire covers for free. Couldn't pass it up. We might try the two-toned brown cover this time.