i stole one of my daughters school bakpaks for work commute , it lasted 6mnths before it completly tore in 1/2 i now use a bum bag she got me for xmas & put my tool-kit in an extra bottle holder, makes riding a lot easyer, i think the bakpak partialy restricted my breathing on the uphill pinches, the bum-bag also restictes the amount of tucker i take for lunch, wich should be a good thing but i usualy end up buying bacon butties & chips for lunch/ tea or brekkies ,depending on what shift im on , bad thing, but then this makes me ride a 50k route home to burn it all off ! but my weight stays around 87kgs so i must have it about right