What is the largest cycling association of the world?

[Belgium]

I know one, but won't unveil yet its name because yours may be bigger ;-)
My favourite one has 70.000 contribution paying members, on a population of 22 million inhabitants.
And what about yours?

[tonythomson]

CTC UK no idea if this is the biggest but certainly is in Britain.

SOBOB probably the smallest with one member - me. But it gets me discounts in motels 

[leo]

The Fédération Française de Cyclotourisme has more than 122 000 members. I think, but don't know, that it's the world's largest.

happy days

léo

[BrianW]

In Germany the ADFC – Allgemeiner Deutscher Fahrradclub - has 130,000 members.

http://www.adfc.de/ueber-uns/ziele-des-adfc/adfc-daten-kurz-und-knackig

[Belgium]

Not bad.  When it comes to absolute numbers, larger countries have associations with more members.  Logical.
But I was clever enough to introduce in my initial message also the size of the population. 
I was rather thinking of 'Vrienden op de Fiets' (Friends on the Bike), with most of it's 70000 members speaking Dutch (because of living in the Netherlands or in Flanders).  On a population of 22 million. 
I think we all know there's no country in the world where the bicycle is so omnipresent, not only for recreational purposes but in daily life as well and that's the Netherlands.