New Sirrus owner here! Snagged a 2016 Sirrus Comp Disc from my LBS's used/trade-in rack. I took it for a longer ride yesterday, and was thinking I might want to change out the stock 700x30s that are currently on it. My most frequent riding partner (my wife) just got herself more of a cruiser/comfort style (Norco Scene 1), as she doesn't want to feel forced into riding her Kona Jake when we're looking for a more leisurely trip. Because of this, I'm not as concerned about trimming off some of the "top end" to give myself more flexibility when it comes to gravel and trails.

Any suggestions on what size I should and/or could be looking for? Any suggestions on tire brands?

Taking a quick measure of my forks, it looks like 40s could fit comfortably. That's slightly outside the range specified in the link posted here previously (sheldonbrown site.. I'm not allowed to post URLs yet!) as I believe the interior rim width for these wheels is 17. 40s might also make off the shelf fenders a no-go, so I don't know if going that large makes sense? Browsing this thread, it looks like a couple people have upsized their tires close to that size with success.