Like surprise trips to the ice cream parlor and lazy afternoons on the beach, tire swings are a necessary component of childhood. Here's how to set one up right, with advice from Barbara Butler, a renowned San Francisco-based designer and builder of wildly original play structures (see her designs at barbarabutler.com).

The Tree

A house cannot be built on sand and, likewise, a tire swing cannot be attached to an unsteady tree. Start with a big, strong, healthy tree and then find the perfect branch. A tree specialist or arborist can help here. Barbara Butler and her crew say half of their work is climbing up the tree and testing several spots until they find the best tree limb. They look for a point of attachment that will allow for a good, deep swing arch with enough space to swing without banging into the tree trunk or a fence -- or anything else.

Barbara once built a tire swing for singer Bobby McFerrin's family. She used a tire from her own truck. The swing was great fun but the tire wasn't the best -- the black rubber came off on the kid's clothes and water got trapped inside the rim. These days, they use rotomolded plastic tire swings. You can get them at most any playground supply store and even some toy stores. They're sturdy, lightweight, and sealed so no water collects inside and gets yucky.

Use a coated soft-grip chain, which is easy on kids' hands.

A heavy-duty lubricated tire swivel is best to hang the tire. You can attach it to either a beam that spans two limbs or directly to one strong limb.