So I made the measurement when it was unhitched and it was 4”. Hitched up was 5” and then I put it on 4 chains the tightest I could get it and it measured 4” again. The wind on hwy2 was super strong today but I only really felt it when a large truck sped past me. The trailer never started swaying rather the car felt like it was moving side to side. I averaged about 100Kph.