My current tyres are 235/70 15's Stock as I understand it.
The new ones are 235/75 15's

Also, in addition to the slightly taller tyres & the 4" backspacing, I have the wider fender flares on my truck. (This may of course prove irrelevant).

 

When I had the Bridgestone Duelers 9R15 Lt fitted I had to take an anglegrinder to the front flares so the tyres [tires] didn't catch when turning.

 

sorry mate, forgot which wheels you were running on it. sounds like it's time to get out the angle grinder.
FYI, the 235/70/15 measures 27.95", and the 235/75/15 measures 28.87" (in height). this is a 3.19% difference, which will put your speedo out by 2MPH or 3.2KPH.

 

70 15's are stock, I seem to recall 75 15's being an option. (Thats what came on my truck from the factory).

 

OK! All done. New tyres fitted. I posted in the general section as I think there are more people who don't usually read this section but may find it interesting.

And YES, there are pics!