Motorhome retail fell 4 percent in May, according to the report. Winnebago unit retail improved 8 percent in May, but Thor unit retail fell 18 percent.

Class A registrations increased 6 percent in May, reversing a slight decline in April, according to Baird. Class C registrations in May decreased 14 percent, the third consecutive monthly decline. Motorhome retail performance remains up 3.5 percent through May this year.

The seasonally adjusted annual rate (SAAR) of U.S. motorhome retail registrations for May fell to 20,100 units, from 21,600 units in April, according to Baird. U.S. dealers sold 19,800 motorhomes in 2011.