Suitability of tyres on rims

dirtbiker100
dirtbiker100 Posts: 1,997
edited September 2007 in MTB buying advice
I have some Alex TD-20 rims on my marin full sus with 2.35" knobbly tyres but I am going to be getting some slicks for the wheels, long story, what size can I use?
Do I need to measure the rim width first? was thinking of getting some 1.5" width slicks but I don't know if this will be too narrow?
thanks

edit
can only find specs of TD17's on alex website:
http://www.alexrims.com/product_detail. ... at=2&id=56
whats the difference with the 20's do you think?