TWO Premium 4.00-19 Farm Tractor Tire Inner Tubes Some Ford 8N 9N WO new premium quality Korean made tire inner tubes (not cheap chinese) for use in 4.00-19 size tractor fronts. This size is commonly found on the front of Ford 8N and 9N tractors however check your size before ordering as they also used some 16". This tube also fits the 4.00-18. Tube has the TR15 stem.