Homemade trailer tire rack ideas??

Need some ideas on a cheap way to make some tire racks. Thanks for the help
I used 3/4 emt electrical conduit and 3/8 plywood for end caps and middle support. Emt is lightweight and cheap. Comes in 10ft. lengths. Drill holes in plywood to slide conduit though and secure with emt connector on each end. Space pipes far enough apart for tires not to fall though. Too close and your tires will bounce out going down the road. Every thing is availiable at Lowes or Home Depot.
I was gonna post same then read your post, wooden blocks as ends and supports drilled for PVC, then drill PVC and place a bolt at ends to keep it from sliding out.

That would work good. I make mine as a rack that stands on the floor all pvc. I run a strap trough the rim holes and around pvc to keep the from bouncing out. The reason I make mine freestanding is so when im at the track my tires are next to my kart so I can swap at will and place used on rack. When im done I unload all my tires at once into shop for cleaning and prep. Race time I just grab rack and go....lol. Works really good for out of truck bed racing and or traveling with another crew. I also made a large rack in my shop that holds all my sets. If I need more space I just pop top caps off and add another level... Its cheap and easy to build...