Can 2007 - 2019 Toyota Tundra coil overs be upgraded to a heavier rate coil spring?
No, Icon does not offer a heavier rate coil spring for the 2007+ Tundra. There are other spring manufacturers that make a coil spring of similar dimensions to the icon coil spring, however the max thread showing would have to be calculated based on the specifications of that coil spring. If more lift is desired the ICON bumps on spacer is recommended over switching to a different coil spring.
51046 - 07-UP TUNDRA BUMP STOP SPACER KIT