How close is too close - High mount exhaust

Hey guys,
Just installed a high mount exhaust this weekend on my 01. I have a oval Scorpion exhaust and I was a bit concerned about how close the can is to the tire in one section. In the section where the pipe meets the can that section is about 1/2 inch from the tire, but only for about 3 inches worth. It is a tight fit so the muffler is not moving around but my concern was about the heat so close to the tire. I still have the underfender attached and it is about the same distance in a spot and it didn't melt. Am I just parnoid for no reason. No pictures yet.
How close is too close?????
thanks
Tom
www.tomspinballcycle.com