Re-design messenger bag strap so that it doesn't slide or bunch at the loop
I have a Clive messenger bag that is perfect for my carrying and commuting needs, except for the strap. The material of the strap is pretty flimsy, not the tough woven type as found on timbuk2 or Chrome messenger bags. If the bag is too heavy (with books, etc) the strap slides so that it's too long.
The strap is sewn into the bag on one side, and on the other side, the strap goes through a small (maybe 5 mm diameter) metal rectangular loop. The strap always bunches and the loop hangs vertically so that the tab connected to the bag and the bag strap are all bunched.
Does anyone have any ideas on how to re-sew or replace the strap and/or loop so that the strap doesn't bunch or slide?