Finned vs smooth brake drum

roccodart440 said
Fins dissipate heat, couldn't hurt

S'cuder said
Improvement? Yes. Noticeable improvement? Maybe. Big improvement? Even at peak efficiency, 9" drum brakes are limited as to their effectiveness versus larger drums and discs. Brakes convert kinetic energy into heat, so any way to better dissipate the heat will improve their function. Fins increase the surface area from which the heat can be released, providing better cooling.
If you can find them, try them. As long as you have the brakes apart, consider changing the shoes to those with an aggressive lining material.
Enjoy you scenic driving! I looked at a satellite view of Andalucia and along with mountains, saw olive groves that seem to go on forever.

Exactly! The fins actually add a lot of surface area, which will help heat dissipation quite a bit. Thermodynamics is all about surface area.

Will it make a huge, noticeable difference on the road? Probably not. But it will definitely improve heat dissipation. If you can’t change them, you might as well make them as efficient as possible with the finned drums and better shoe compounds.

Murray said
It is doubtful that you will ever exercise your brakes enough to test the effectiveness of finned drums versus smooth. If you plan on doing a lot of heavy braking as in road course racing or continuous heavy mountain travel then you need to consider converting to larger disc brakes.

C’mon man. She already said she can’t change the brakes because of historic car regulations where he’s at and his 13” wheels. And 9” drums can heat up pretty fast. Maybe it’s not gonna be a night and day difference but every little bit helps.