Ah, ok. I'm not familiar with the terminology, and am mystified as to why a different unit of measurement is required for moutain bikes vs. road bikes, lol. I thought I saw 29" and 700c used interchangeable somewhere and so concluded that they must mean the same thing, but I guess that is either incorrect or at least gauche.

So I'm shopping for a bike, and some of the options I'm looking at have 700c tires, which I understand to be faster on the road, but less safe on the trail. And my current bike is a mountain bike with 26 inch tires of some fancy variety that don't get flats. So I thought, well, maybe if I did end up getting one of the bikes with 700c tires, I could put my 26's on instead. But I guess the answer is probably not?