Hello there, last year i built my girlfriend a bike up using some old spares. I need to get here some new chainrings but my memory is that I was previously told that they use a different BCD to current shimano chainsets.

They look like this:

What rings do these take?

they look like normal BCD to me (104 larger ones and 64 inner) but it looks like the large ring on those in the pic is a touring 48T (44T is the norm for off-road 9 speed).

Part numbers here: http://techdocs.shimano.com/media/techdocs/content/cycle/EV/bikecomponents/FC/EV-FC-M572-2188A_v1_m56577569830611899.pdf

As it’s an older series it doesnt have the compatibility chart but google the prt numbers or rings for the crank part number and you should find the BCD.

Basically any of the lower end chainrings would be your cheapest and most reliable (steel rings) bet.

edit: just noticed my link does indeed include the BCDs.

Ive just had some chainrings off this guy http://www.dalesbikedoctor.co.uk

he seems happy to help and have a conversation about what will and wont fit, pretty cheap too