Still using my dad's home made box trailer with 50 year old tires with tubes. Some of you may remember the tire size 6.00 x 16. Probably can't get new tires for it any more. I check the visual condition of the tires and they still hold the air well. I have been thinking of replacing the trailer for years but it still does the job. I don't use it much but when I do take it easy, stay on the right side on the road, have no spare tire.