will an 18 inch rear tire/wheel rub on my 2005 softail deluxe?

 

Compared to what is on there?
I have no clue

 

well, I was told that there would be a better chance of it rubbing the fender if and when I went riding - 2 up that is...

 

Help us to help you! What size tyre do you have in mind?

Tyre sizes are not always logical. As an example, Harley has used front wheels on some Touring models in 16", 17", 18" and 19" diameter rims. However the tyres on each rim are of such a profile that they all have a similar rolling diameter. So in those cases there will be no risk of rubbing. If we know the size of tyre for your bike we can offer an opinion.