The phrase "keeps one shoulder to the wheel" is an idiom that means to work hard and persistently at a task or goal. There are several synonyms for this phrase, including "perseveres," "endures," "slogs," "struggles," and "labors." "Perseveres" suggests a sustained effort despite setbacks or obstacles. "Endures" implies a willingness to withstand discomfort or hardship without giving up. "Slogs" indicates a laborious or tedious effort. "Struggles" suggests an effort that requires strength, resolve, or perseverance. "Labors" suggests a sustained effort that requires hard work and often involves physical exertion. Whatever synonym is used, the underlying message is the same: success requires hard work and a persistent, determined attitude.