Check out Kestrel’s “Ask a Pro Section” on their website!
http://www.kestrelbicycles.com/Explore/ASK-THE-PROS.
I just got my first question. Check it out!

Message: Is 650 dead? I am a short rider and concerned about getting a new 650 bike. Tires/tubes hard to find, especially on the course…as you know. Companies that make 650 bikes say they are the only way to go. Companies that make 700 bikes says that THEY are the only way to go. Your thoughts?

The question concerning 650c wheels vs. 700c wheels seems to be a HOT topic these days!
When I first started racing triathlons 12 years ago, 650 wheels were the ONLY way to go. It was not unusual to see a 6′ 2″ guy on a tri specific bike with 650 wheels. It looked “funny”, but 650c wheel were all the rage!
Somewhere around 2001/2002, the tide started to change. 650c wheels were no longer popular and bike companies stopped making the bikes, which was unfortunate for folks under 5’6″.
Lucky for us smaller riders (I am 5’7″), 650 wheels are making a comeback! While I do not consider myself short, I find myself in between sizes. I can go with either a 700c bike or a 650c bike. With a 650c wheels, however, I have a shorter reach frame with the proper head tube angle for good control and I never have toe “overlap” with my front wheel. With 700c, I did. I always had to be careful when making tight turns. But now, with 650c wheels and a smaller frame, I feel more in control. I am able to “man handle” the bike, take tight corners or bomb down mountains without hesitation. I love tucking in behind the bigger riders on group rides. It is my “Porsche”.
When someone asks me if my 650c bike is as fast as a 700c bike, my first response is: Is a small car as fast as a large car? All kidding aside, I believe that as long as the gearing is correct, there should NOT be a difference as to which size bike is faster. If bigger wheels made us faster, then bike companies would be making 800c wheels!
I think that if you are a smaller rider, under 5’6″, there is no question as to “if” you should be riding a 650c bike. A smaller bike with smaller wheels will fit you better!
I am hopeful that since a lot of the professional women (world champion, Mirinda Carfrae, Yvonne VanVlerkin, Jo Lawn, and myself) are now riding 650 wheels, races will take note. I hope we have tubes/tires more available on course. For now (since my double flat in Branson) I have taken more precautions. I take one extra tube with me while racing. Obviously the goal is not have a flat tire. I now consider the sag wagon a luxury and it should not be a necessity.
Good luck with shopping for your new bike!
650c bikes RULE!