The nice part about700 c tho is that they come in all kinds of widths-
i've heard conflicting stories about fit tho- I'll go looking for some more answers- I've heard from one track racer that not more than 28mm (1 1/8") will go on a narrow road rim, but I think there are three separate widths of rim, or more, out there.
just last week I asked a vendor on ebay if a 35mm would fit on my rim- his reply was "if it's a 700 rim, it will fit"- I'm not sure- vendors say stuff they don't know about some times to make a sale.
Anyway heres how the conversion works- if you don't know already:
1 inch is 25.4 mm
and so the 700tires in mm sizes are
25mm- 1inch
28mm- 1 1/8'
32mm- 1 1/4
35mm- 1 3/8"
38mm- 1 1/2" (1.5)
42mm- 1 3/8"
you get the picture- roughly every 3mm is 1/8' , and 25 is the 1 inch starting point
I've got a 27 x 1 1/4 on the front already and I'm probably gonna put a 27 on the rear- I've just discovered the long lost 27 x 1 3/8 tire, that I will probably use there, for a slightly wider stability- a cruiser that wil roll about as well as a ten speed. Right now it's got a 1.75 26 on the back- I was gonna go to 1.5, but I have an alloy 27 wheel already, and a hub grooved rear hub of the right diameter - so I'm going even lighter
With a 36 sprocket, I'm sure I'm already topping 30 when I want to, but I never really open it up.
The other build slowly coming has 700C wheels-
http://motorbicycling.com/f15/sprocket-bolted-drilled-flip-flop-24770.html
I'm thinking I might put a 38mm on the rear (1.5") if it will fit on the rim- and probably a 32 on the front (1 1/8) because it's only a 50 motor and you can get by with a smaller width on the front- I ride on flat urban streets for transportation-