I have 245/70r17 Duratracs and I don't know if you'll be able to fit 245/75r17's without some spacers. That being said, I've heard of people fitting 265/65r17's without spacers on stock rims so the only way you'll know for sure is to have them test fitted. Here's a picture of my 245/70r17's:



I can get a better picture if you want.