When you’ve made the trip more than two-dozen times you like to go with friends. RAGBRAI participant Jon Cook is making his 28th bicycle ride across Iowa, with a bike club called the Tall Dogs.He says while they camp in various places it’s always people someone in the group knows, a shop building or yard where someone asks permission from the neighbors, too. He says “we’ll camp all over that block.” There are about 80 members in the Tall Dogs, and Cook says it’s not at all unusual for people to make friends and form groups. So what’s it sound like to pedal down the road surrounded by 20-thousand bikes? Cook says you hear everyone shifting gears, but when there is a tailwind going down blacktop he describes it as an interesting, calming sound.This year there are 85-hundred participants, a strict limit imposed since the days when ridership reached more than 20-thousand and became an uncontrollable mob scene. And a group called “Pedaling for Parkinson’s” is studying the effects of the great bike ride on the disease, to see if pedaling faster can release more of the brain chemical dopamine. That would be a good sign for Parkinson’s patients that exercise would help them stave off the effects of the disease.