With a Basic Class C License:
a 2-axle vehicle with a GVWR of 26,000 pounds or less.
a 3-axle vehicle weighing 6,000 pounds gross or less.
a motorized scooter.
any housecar 40 feet or less.
A farmer or employee of a farmer may also drive:
any combination of vehicles with a Gross Combination Weight Rating (GCWR) of 26,000 pounds or less if used exclusively in agricultural operations and it is not for hire or compensation.
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Above is from "California Driver License Classes" that toedtoes posted.
Looks to me anything over 26,001 lb or over 40 feet needs the Class B noncommercial license.