On the back of my bike, on the frame, there are 4 threaded holes, two on each side, for attaching a fender and a rack.

For my bike, the bolts to use are "Cap screws".

The size is "#10 - 32 - 1/2 inch", according to Canadian Tire.

Maybe these are the same size for your bike.

by rob at 3:19 AM under bike (Comments)