this sport doesn't have to be fancy. any bike w/ two wheels will work (except for those crazy recumbents) mtn and hybrid bikes are normally at the racks at tri's.  definitely get yourself some good running shoes (not tennis shoes) and start out slow even allow for small walking breaks if you need to. actually when starting out just keep your pace for the bike and run at conversation pace - if you can't talk you're working too hard! check around for a local running/cycling/tri club to keep you company and help you out in the start. hope that helps!

Crazy? Absolutely not! If you're swimming an hour a day,  you've already conquered the part of a tri that frightens most of us.

Being active and pushing yourself to a new challenge is never crazy. I agree with the advice to start slow. Make it your goal to finish, not win. And, look for a sprint tri to start with so the distances aren't long. Allow plenty of lead time to prepare. If you've not done any running or biking, I'd suggest at least 6 months to build up to the necessary distances. Personally, I'd also recommend finding someone "crazy" enough to do this with you. Training alone isn't much fun and takes a lot more self-discipline. Having a partner holds you accountable and "forces" you to show up for training runs or rides.

Mostly, have fun and be proud of yourself for staying active.

I just finished my first triathlon.  I did the Danskin race which also has a training component.  It is an all women event and is geared toward first timers.  It was a great experience!

Welcome to triathlons!  I was 54 when I first did a tri (offroad) - with my daughter.  She found some workouts online to gets us started - and we're still doing them together.  It's not crazy - just a new chapter in your life.  Once you've finished a tri, consider yourself a triathlete, and you'll be hooked.  Look for a sprint distance event.  The Danskin and Tri for the Cure are great events for newbies.  As a swimmer, you have an advantage over many - being comfortable in the water is hard for many triathletes.  As for the bike, for a beginner, a hybrid, mountain or road bike will work just fine.  Make sure you get good running shoes to train in, and race in (your knees will thank you).  Tell your friends about your new adventure - they'll come to support you; and it keeps your training incentive high.  My kids and I are doing an offroad tri in Vail this summer as a team (I get to do the mile swim in a mountain lake), and I'll do a sprint tri in Denver this fall.  My goals are simple - finish with a smile on my face!!

Good luck with your new adventure!