Originally Posted by
Panthers007
700C is what you are trying to refer to. It's not 700mm - it is in fact 622mm. The 700C designation comes from France where they tinkered with 700A, 700B, 700C, etc. The '700' itself is a misnomer that has nothing to do with the actual diameter of the tires/wheels.
I should have said the standard "designation". In the US, you'd have trouble asking for 622mm tires. Nearly no-one (in the US) says anything but 700C for this wheel size.
(Example:
http://www.surlybikes.com/frames/lon...trucker_frame/)
The 700 number is related to the overall diameter but the actual diameter varies with the tire width. The metal rim doesn't change diameter. So, it
does make more sense to refer to the diameter of the rim!
700C/622 rims are fairly unusual for mountain bikes. (At his budget, I don't think he needs to be concerned about "29'ers".)
If people are interested in the odd designations for wheel/tire sizes go here:
http://sheldonbrown.com/tire-sizing.html
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In terms of buying bicycles, it's basically a choice between two wheel sizes: one called "700C" (for mysterious reasons) and one called "26 inch" (for mysterious reasons).
The 700C (622mm rim size, standard for road bikes) is larger than 26 inch (standard for mountain bikes and small road bikes.
There is also a "29 inch" wheel (also 622mm rim size) for mountain bikes but these are not that common (yet?) and tend not to be available in the low end of the range.
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For the sake of completeness, there's also a 650B wheel size (smaller than 700C and larger than 26 inch)!!
http://www.rivbike.com/article/misc/...0c_conversions