Which new Tony Hawk's Pro Skater 4 trick transfers between back-to-back quarter-pipes?

Tony Hawk's Pro Skater 4 introduced the spine transfer, a trick that moves a skater between back-to-back quarter-pipes.

A spine transfer is performed when two quarter-pipes meet back-to-back, forming a narrow raised spine between them. Instead of simply launching away or landing on the same ramp, the player can transfer across the spine and continue into the opposite quarter-pipe. The move adds another way to preserve momentum and extend a combo.

The trick also has a practical recovery function. In Pro Skater 4, it can help a skater self-right after flying off a quarter-pipe or avoid a bail in situations where a normal landing would fail. That makes it more than a flashy scoring maneuver: it is also a tool for navigating parks and correcting awkward trajectories.

Boneless, nollie, and wall plant are separate skateboarding moves or game mechanics. They do not describe the specific quarter-pipe-to-quarter-pipe transfer introduced in this installment. Pro Skater 4 also changed the series' career structure by allowing freer exploration and goals offered by characters in each level.