I'm an avid gal cyclist who loves the challenge of an occasional 200 mile ride but rides more consistently between 60-100 miles in one ride. I am 5' 3", currently own a bike with 700c wheels, am looking into buying a new and possibly custom fit bike and am confused as to which rims I should get. I do just fine with the 700c wheels and as for my toes hitting the wheel during sharp turns, I haven't had a problem yet. I have spoken with one frame builder and he seems quite adament about putting me on a bike with 650c rims. Do I want this?

My 5'3" wife rides a Trek 5200wsd with 650c wheels and she loves it. My triathlon bike has 650c wheels and I'm 5'7" (but my inseam is only 28.5"), however my regular road bike is 700c. From my experience, wheel size matters less than other factors such as frame material, frame geometry and paint color :-).

Read the following article: https://www.slowtwitch.com/mainheadin...650ctoday.html
Even though the article's primary audience is triathletes, it does a good job of discussing some of the differences between the wheel sizes.

I own 2 650c recumbents. I've found no disadvantage to 650s vs. 700s and I have over 100,000 miles on 700s.

I currently run Velocity Spartacus Pro wheels and Mavic Ksyrium Elites. Velocity also makes Uriels which are nice. If you have the cash, there are high-end wheels available like Hed 3s, Zipps, Rolfs, etc.

Some frame builders claim that you can't build a frame with proper geometry for someone under about 5'4" with 700 cm wheels. One solution a number use is to have 650 cm in the front and 700 cm in the rear.

Wheel size is not nearly as important as wheel construction and tire choice. The biggest drawback of 650 is there is not as many choices as in 700.

The efficiency of 700c vs 650c is a moot point so you should ignore that aspect. The cons are mainly the availability in non-specialist bike shops o 650c.
The reason for putting 650c in smaller bikes is to fit into smaller frames. They enable the frame to use better proportions, without having to bodge the head-tube angle or fork rake. A smaller wheel creates a more compact bike that is easier to handle.
The boundary between a small 650c frame and a small 700c frame is about 5'4". You are right on the borderline so it is not an easy choice.
One alternative, if you are NOT racing, is to use 26" MTB wheels. You can easily source narrow 1" tyres and spares. Many UK Audax riders use MTB rims, you can get lightweight rims and build them onto road hubs.
One of the best UK builders of small bike is
https://www.robertscycles.com/products.html
He makes small bikes in 700c, 650c or 26" according to taste.

Thorn have a good article on the advantages of 26" wheels at
https://www.sjscycles.com/thorn/26sol...002/solop3.asp

There is some good advice on womens custom bikes at
https://www.girlbike.com/custombike.html
And a top builder of womens frames is
https://www.lunacycles.com/

Heh, I want to see a children's bike with 700c wheels. The kid would be planted between the wheels instead of on top, but with a centre of gravity that low it would be very hard to lose balance!

Balance comes from a high center of gravity. If you don't believe me, balance a broom on the palm of your hand and then balance a ruler.

I rode 4,500 miles last year on 650's. I'm 5'1 1/2". It's been 10 years this summer that I switched to 650's and there is no reason in my mind to go back to 700's.
Kathi

That's what I was thinking, for tire availability. Maybe get one nice set of 650c road wheels for the road bike but build up some beater everyday wheels using mtb rims and the narowest slicks I can find.

are we trying to confuse the newbies here?
700cm wheel???
That's a 23 foot diameter!
700c wheel!
700mm is 27.5 inches, which makes more sense.

So with that in mind, why are they called 700c instead of 700mm?

Nope, lower center of gravity is better for balance. As the center of gravity approaches the pivot point (the broom gets shorter and closer to your hand) the object becomes more stable and easier to balance. You can't compare a broom to a ruler because of the size of the base and the weight. A ruler is difficult to balance because it has a very thin, asymetrical base that is more prone to tip the whole object over. A better comparison would be a full length broom (~5 ft or so?) to a cut off broom handle (maybe 1 foot?).