Sonic Retro, “Sonic Physics Guide: Rolling”

Cite as: Sonic Retro, “Sonic Physics Guide: Rolling”
Original: https://info.sonicretro.org/index.php?title=SPG:Rolling&oldid=355949
sha256: fef6622d1d34b955bbf9d651ce659c869801ca108044e713c11cc2467a528535
Archived: https://web.archive.org/web/20250716160204/https://info.sonicretro.org/SPG:Rolling
Accessed: 2026-10-21
Credit: Sonic Physics Guide, written and maintained by the Sonic Retro community.
Notes: Revision oldid=355949 ("last edited on 6 June 2023"), read from the Wayback copy because the live site serves a bot challenge.

Cited on

In the running game, on flat ground, Down without Left or Right curls Sonic into a roll when his ground speed, after this frame's friction, is at least `$80` either way: from `$8C` written in by the probe he rolls, from `$8B` he doesn't.	`Criteria`	Verified
In the running game, on flat ground, a roll never speeds up: friction takes `$6` a frame whatever is held, holding against the roll takes another `$20`, and a ground speed past `$1000` written in by the probe gives an X speed of exactly ±`$1000` (16 px/frame).	`Constants`	Verified
In the running game, on flat ground, with the slow ground speed written in by the probe, holding against a roll turns it around only below `$20` moving right but up to `$20` moving left, then friction leaves `$7A`; other slow speeds stop and stand Sonic up.	`Deceleration`	Verified
In the running game, on flat ground, after a jump from a roll the d-pad does nothing in the air, neither steering Sonic nor turning him, and air drag still runs.	`Rolling Jump`	Verified