Eliminating fenders on race cars started in order (1) to make it easier to cool the poor brakes on early race cars, (2) to reduce significantly the weight of the car by allowing a narrower body (lower weight allowing the fastest acceleration with a given engine size or power output), and (3) to facilitate quick changes of wheels/tires during stops during longer races. The latter two virtues are still true, and “no-fenders” is still part of the rules for Indy cars and for internationally organized Formula cars. Dirt-track “Sprint” cars and many other grass-roots forms unique to the US also frequently follow the no-fenders rule.