Didn't you already have another thread asking this same question? Just look at the tire spec sheets made by the manufacture and go off of that keeping in mind that you want to keep the overall diameter of the inflated tire within 3% of the original.

 

I did but I wanted to put the question up to a vote. I have looked at the tire spec sheets I know that it isn't advisable, but at the same time a lot of things we do in everyday life aren't advisable. I just wanted to get peoples' experiences who are running these sizes.