Based on this product's specifications, here are some alternatives and similar models
Front Caster Wheel for iRobot Roomba I4 I5 I6 I7 I7+ E5 E6 E7 S9 — JETtools SB9257
Summary description:
Replacement front caster wheel compatible with iRobot Roomba models I4, I5, I6, I7, I7+, E5, E6, E7 and S9. Manufactured by JETtools (MPN SB9257), this spare part restores steering and front-wheel movement after wear or damage. Intended for do-it-yourself maintenance and quick repair of robot vacuum mobility and navigation on hard floors and low-pile carpets.