Dumb question about inner tubes

ashura said:

[font=Tahoma]Hi guys,

Sorry about this dumb question, I'm new and lack with bike knowlegde.
My road bike tyres size is 700x23 <--- 100% sure 😄
I would like to purchase spare inner tubes and I found, it's a bit confusing for me about the thickness: 36mm, 48mm, 60mm
for example:
[/font]A. Continental 700x18-25 Race Light 36mm Presta Tube
B. Continental 700x18-25 Race Light 48mm Presta Tube
C. Continental 700x18-25 Race Light 60mm Presta Tube

Which will fit my tyre size? A, B or C? or all of the above?

And should I look only 700x23 excatly match asmy tyre size? means not in between like the above example 700x18-25

And also feel free to suggest other inner tubes brands that are cheap, tough, reliable and less confusing 😄

Thank you so much in advance and all your help
Haris

The 700 by 18-25 is the right size tube for your bike.
The 36mm, 48mm, and 60mm are describing the length of the presta valve stem that you use to inflate the tube.

The short ones are for traditional rims with no aerodynamic profile (such as Mavic Open Pro), the 48mm are for moderate aerodynamic profiles (such as Mavic CXP-22), and the 60mm valves are for full aero-wheels (so expensive I really doubt you have a set.)

If you are not sure what kind of rims you have, then just measure the presta valve stems on your current bike and buy a pair that have the same length valve stem.

Hope this helps,
Cheers!