one google away, you could try just a lil harder...
http://en.wikipedia.org/wiki/Flip-fl...track_bicycles
The most common standard I.S.O. thread size is 1.375" x 24 tpi (threads per inch), but there are other less common older sizes (British 1.370" x 24 tpi, French 34.7 x 1 mm, Italian 35 mm x 24 tpi).