Best/largest tire you can safely fit on a stock 15x7 rim?

[t-topflyer]

I'm interested in putting stock size tires on the front of my TR and something larger on the rear. Maybe a drag radial or just a larger tire. What's the biggest one you can put on the rear without any alterations or problems such as spacers or rubbing? Also, what's a good brand to look into?

 

[87GN_ponykillr]

I run 275's Eagle GT's on the back of my GN and 225's on the front. It gives it a nice rake.

 

[turbocam]

tires

i ran 275/60s on my car with no issues. i have 275/50 et streets now with a small spacer, no problems.