28 x 1 1/2 = 700c?

[MiddleAge]

700c is ETRTO 622.
27" is ETRTO 630
Haven't got a clue what 635 could be, other than extremely difficult to get tyres for.
But other people have . . . .
http://en.wikipedia.org/wiki/ISO_5775
http://forum.ctc.org.uk/viewtopic.php?f=5&t=36249

 

[Macflame]

Many thanks for your quick and helpful replies.
I am going to try and make sense of it tomorrow after , hopefully, a good nights sleep.
I have some wheels at the back of my shed, which might help make sense of all this.
I have never had trouble like this before but the BiFrame is a bit of a hybrid.

 

[eastsidebikes]

635 ERD is a size used in some dutch bikes, really unusual over here. I've got a pair of brand new schwalbe 635-60 big apples in the workshop. I have no idea how they got there :? Maybe I thought they were 29er ie 700c tyres

As an aside, 28" is sometimes used to describe 622, also known as 700c. Schwalbe for example mark 622-32 tyres as 28x1.25

So many names for 700c

 

[Macflame]

I dug out a pair of 27" wheels from my shed and the new '26"' tyres fit!
I trundled down to my local bike shop. Presented my 26" rims (that wouldn't take the new tyres) and had 26" x 1.50 tyres fitted.
I'm still scratching my head but at least I am mobile again! I also have an incentive to clean up an old frame for the 27" wheels.

Thanks again for all your replies and suggestions.