If one of your mates has recently bought a new aerodynamic roof rack, they may be constantly bending your ear about how great the rack is and how much money it will save. You've also been thinking about fitting a new roof rack, but haven't considered stuff like aerodynamics as being that important.
Is your mate talking rubbish, or should you go for an aerodynamic rack as well?
How Do Roof Racks Affect Aerodynamics?
Without a roof rack, your car has the best possible aerodynamics for its design. As you drive, air passes over your car smoothly and without interruption from the front to the back of the vehicle.
Things change with this flow if you put a roof rack on top of the car. As air goes over the car, the roof rack acts as a blockage. Air can't travel smoothly over the vehicle any more. This increases the drag on your car, which in turn affects the way the car handles. It takes less power to drive with a lower drag than it does with a higher one.
How Do Aerodynamic Roof Racks Work?
While anything you attach to the top of the car affects its aerodynamics, some roof racks are less disruptive than others. Aerodynamic roof racks are designed to block as little airflow as possible.
So, for example, an aerodynamic design will give a roof rack a compact footprint that doesn't get in the way of airflow as much. These racks tend not to have any solid areas that block air, and they are also often made from lighter materials.
When you have this kind of rack on your car, your drag still increases; it just doesn't increase as much.
Do Aerodynamic Roof Racks Really Save Money?
If a roof rack increases drag, then your car has to work harder to move forward. Drag forces hold the car back; you'll have to use more power to get up to speed and stay there. When this happens, your fuel consumption increases. You use more gas to meet the car's extra power needs.
If you're using a regular roof rack, you'll have more drag to deal with. If you use an aerodynamic model, there won't be as much drag and you won't need to use as much gas. So, your mate is right — this could be a good investment.
To check out roof rack options, visit your local auto parts store and take a look at their aerodynamic racks.