Originally Posted by
Slaninar
I strongly disagree.
How much does a rack cost? In stead of sweating all the way, you just put your backpack on the rack. I wouldn't ride a bicycle that doesn't have a rack unless no alternative was available. On a hot day, I often take my shirt off on climbs, and stuff it all in the backpack, so I sweat less.
To each his own, I guess.
I have an almost identical commute as the OP (3 miles one-way, with a 100-ft drop in elevation towards work in the morning) also in Southern California and I have been happy and sweat-free using a backpack for about 10 years.