I decided to pick up a smaller lighter backpack, both for general use when biking and bearing in mind that it could work better for the simple one-camera/one lens combination like the Canon 5D and the 24-105 lens I carried yesterday in the big photo gear backpack.
So, I tossed the combo into the pack, found the camera protruded into my back too much, stuffed in a wadded tee shirt, was happier, grabbed my bike and took off down the road to ride and take pictures!