Roof racks cut EV range significantly


A new study by EV battery diagnostics firm AVILOO reveals that roof-mounted bicycle carriers can dramatically reduce an electric car’s range. Testing a VW ID4 at 120km/h (75mph), the car achieved 3.5mi/kWh unladen. With a roof-mounted bike rack carrying three trekking bikes, this dropped to 2.3mi/kWh – cutting range by 92 miles.

Drivers travelling at 130km/h (81mph) would need to lower their speed to 97km/h (60mph) to match the original efficiency when unloaded. A rear-mounted bike rack, however, only reduced efficiency slightly, to 3.2mi/kWh.


Nikolaus Mayerhofer, AVILOO CTO, explained: “Rear-mounted racks have minimal impact on range and driving behaviour. Roof loads, however, result in noticeable losses due to air resistance, which increases quadratically with speed.”

Tests were carried out at night in Vienna, over a fixed 60km route, using cruise control, consistent tyre pressures, and no air conditioning. The uniform test conditions ensured reliable, reproducible results, highlighting how roof-mounted carriers can seriously impair EV performance.

FleetWise editor, John Sootheran, said: "As these results are so dramatic, Fleet managers should consider sharing this information in their EV Driver Introduction Packs."

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