Bicyclists are gearing up for a Sunday ride to benefit the American River Parkway, which faces reduced funding this year. By Monday afternoon, 233 people had already signed up for The Rex Ride, a barbecue/party centered around an up-to 60-mile, low-key ride on the Jedediah Smith Memorial Trail -- also known as the American River bike trail. The 32-mile, multi-use trail is used year-round by virtually everyone in Sacramento's huge cycling community, said event organizer Steve Rex, who owns Rex Cycles bike shop in Midtown. "It's huge. It's the focus of the cycling culture that's really rich here in Sacramento," said Rex, 47. A serious cycling injury last fall isn't stopping Rex and his wi