Is there a chart somewhere that lets you know the maximum tyre width on any given wheel rim, for example can you get 185/60's on a 5" rim etc?

thanks

It's different for each tire. Check the manufacturers site for that info.

Try this link will tell you just about everything you need to know about tyres but for oversizing only use it as a rule of thumb as has been said before it depends on manufacturer

http://www.carbibles.com/tyre_bible.html

Brilliant!!! Found just what i needed.

Thank you!!