If panniers aren't your cup of tea then a backpack with foam padding which allows ventilation would be best.
Ortelieb Velocity works quite well:
Er, no it doesn't. My back is positively drenched using that backpack. What DOES happen, though, is you get a really cool sweat pattern on your back. :)
tombola, the best answer is, ride in a synthetic/quickdry material/merino top, with your good top in your bag, go straight to the bathroom when you get to work, and swap over. Job's a goodun. If you get a quick drying cycling top, it'll be fine for the ride home. :)
Er, no it doesn't. My back is positively drenched using that backpack. What DOES happen, though, is you get a really cool sweat pattern on your back. :)
tombola, the best answer is, ride in a synthetic/quickdry material/merino top, with your good top in your bag, go straight to the bathroom when you get to work, and swap over. Job's a goodun. If you get a quick drying cycling top, it'll be fine for the ride home. :)