Backpack is okay in winter but pain in summer.
I'd just commute in you rapha top, if your backpack is secured it should not move and wear. You've a nice top so wear it.
What do you need to carry? A framebag or saddlebag might be enough. It is worth getting the weight off your back and onto the bike, a lot nicer.
That said, I commuted with a rucksack that distance for 6 months a few years back. Just means sweaty back.
Backpack is okay in winter but pain in summer.
I'd just commute in you rapha top, if your backpack is secured it should not move and wear. You've a nice top so wear it.
What do you need to carry? A framebag or saddlebag might be enough. It is worth getting the weight off your back and onto the bike, a lot nicer.
That said, I commuted with a rucksack that distance for 6 months a few years back. Just means sweaty back.