I picked up a used Trail-A-Bike. The seatpost collar that came with it is for a 27.2 seatpost. Should I get a shim to make up the gap or is collar with a shim inside too many seperate loose items? Or is it necessary to get a single shim/collar to safely cover the entire gap-it looks like the diameter might be 30+mm on without the existing collar.
My best mountain bike and best road bike each use a 27.2, but I'd rather user lesser quality bikes when towing.