It's not like you're going to leave your bikes outside overnight, right?
My GF and I just went there last September and had a stellar time! Best bike town EVER!
Awesome brewpubs, brewery tasting rooms, and distilleries too. We even visited Sky of Velo Cult, which moved from San Diego to Portland. (He's a lot happier up there, and Portland deserves Velo Cult more than San Diego does.)
New Deal Distillery's gin plus these French Picholine olives we discovered in San Luis Obispo on the way back, make the best martini I've ever tasted.
The two brewery standouts were Salem Ale Works, Ninkasi, and Agrarian.
You'll have a great time. If you don't want to worry about your bikes, or if you don't have junkers, there are bike rentals up there. I'm jealous.