i bet with a "higher powered" car, it makes less of a difference,
but i notice it a lot on a stock car, both runs were about a month apart on a friday night right around 50 degrees, and kinda dry outside. so weather was kinda close the only other variable would be the kind of gas i had in the car, with the 15's on i ran premium, i know it doesnt make a difference but i noticed my car runs better with it, and then with the 17's i ran regular gas.
but if you think about it, my chrome wheels each alone weigh 27lbs, and then add a tire on top of that?? what about 40 lbs probably??
alright so a stock 15" wheel and tire is probably 25lbs each
alright 15x4= 60lbs more
i can say with my girlfriend in the car i went from a 15.4 to a 15.9 on the same night at the track.
ive been told its not so much the extra weight but the rotating mass that makes the difference...
i guess why do all the guys run smaller wheels (ie 15") on faster drag cars, one the tires but i bet also its the weight.