If you go with the 24" tires and rims you then need to go with a smaller crank arm... otherwise the peddles hit the ground when turning and peddling at the same time. It does not take a tight turn to get this to happen so beware of this... I have a nishiki saga and that has always been an issue with it... it has the 24's on it and a road bike crank for the faster gearing.... that is how it came to when I bought it new.

Good luck