who fully supports my cycling habit, and in fact, may be pretty darn close to developing one herself.

Last year, I signed up for and completed my first tour - a fully supported one of the C and O Canal Towpath. I had so much fun that I already registered for this year's ride. My girlfriend would like to participate in this year's ride, but I am concerned about the bike that she wants to use. She rides a 2014 Giant Liv Avail 2, and it looks like the most she could go on beefier tires is a 700x28, which does not seem wide enough for a trail like the C and O. Has anyone here ever put anything bigger on a bike like this? Or should we start looking for her +1? For me, it would be a no brainer, I would just buy a new bike, but she is more budget conscious than I am, which is another thing that makes us a good fit - making me think twice about ridiculous purchases since I live in a town house and between my bikes and my kids' bikes significant wall space is occupied by bicycles.

Thanks in advance for any assistance.