I run 28c Conti GP 4 Seasons on my commute bike. I was riding home tonight in the rain, and dropped my front wheel into a crack between the bike lane and the road. I knew about the crack, but could not see it with the puddles and the rain obscuring my vision. I was glad to be riding the wider tires, 23c would have scraped my rims, and perhaps even take me down. I say definitely go with the larger size.