What would make the difference in how it rolls? Bearing quality? or just the shaft diameter itself? First build so just tring to under stand.
If it rolls hard it takes more horsepower to turn the tires= slower speed= being less competitive=worse finishing spot= not as much fun. Get good quality bearings. I recommend using the 1 1/4" axle with the free spin bearings, and it is no lie the bearings are free spin. I am not aware of any 3/4" free spin bearings. I can push my race mower with 1 finger using little effort in doing so.