Welcome to the site.

This issue has been discussed several times, and here is an example I found in a couple of minutes looking through the previous posts.

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1344301841

This site has a lot of helpful stuff.......read through old posts and you will probably find what you want to know.  Try to use the search function, the Table of contents in the Tech Session, or just scan through the old postings when you can.....then if you can't find it we can probably help.  

If you run any wider than this, you'll need to consider running a chain.

I think 160 either gets real close or touches.

and the rim is kinda narrow for the 140.