My research tells me that the 2021 Newmar Bay Star Sport Motorhome is built on the Ford F-53 chassis. In this case, there are actually not any custom-fit floor mats for this vehicle, however, you can go with a universal fit such as WeatherTech All-Vehicle Mat Auto Floor Liners - Front and Rear - Gray # 61-11AVMOTHSG. These mats offer a trim-to-fit design so that they can work with various vehicles. view full answer...