2002 Chevrolet Blazer Tires

Wow, I can't believe no one will help you with this. Let me explain something so you understand. The tires you presently have, 235/70 R15 and the 235/75 R15, are both a 15" tire. That means they must go on a 15" rim. The only difference is the middle number (75 vs 70). That tells me that one tire, the 70, will be a slight bit smaller in outside diameter, and a slight bit wider. As long as the rims you have are 15", and they must be since that is the size you presently have, you can do what you explained. Yes, the 235/75R15 inch tires will fit on the same rims that presently have the 235/70R15.