Drivers issued 'clear message' to 'remove' item from car immediately A roof mounted bicycle carrier can have a significant impact on an electric car's range, a new study has found. Drivers urged to 'remove' item from car immediately and 'message is clear' Drivers have been urged to remove an item from their car immediately - because it could increase their fuel consumption by 92 miles. A roof mounted bicycle carrier can have a significant impact on an electric car's range, a new study has found. AVILOO, a specialist in electric vehicle (EV) battery diagnostics, compared the driving efficiency of a VW ID4 when equipped with a roof mounted bicycle carrier, a rear-mounted bicycle carrier and with no bicycle carrier. ‌ “We want to bring clarity with our study,” explains Nikolaus Mayerhofer, CTO of AVILOO and test driver for all test rounds. “There are many half-truths about extra consumption due to loading. Article continues below READ MORE Exact dates next UK mini-heatwave start and end with 72-hour scorcher set to hit "Our measurements clearly show that rear-mounted racks have minimal impact on range and driving behaviour. Roof loads, however, result in noticeable losses. The main physical reason for the clear differences is air resistance - it doesn’t increase linearly but quadratically. ‌ "At double the speed, air resistance increases energy use fourfold.” GoSkippy added: “The heavier your car is, the more fuel is consuming. A lot of us might use our car as a bit of a dumping ground for things we don’t need immediately. “By having a clear out, you can reduce the overall weight your car needs to propel up the road. This could be small things like rubbish and clothes or larger things like removing a roof rack when it’s not being used.” At a cruising speed of 120 km/h (75 mph), the ID.4 delivered approximately 3.5 miles per kilowatt-hour. However, with a roof-mounted cargo carrier installed, efficiency dropped significantly to just 2.3 mi/kWh. Article continues below This cuts the vehicle's total range by about 92 miles, the sutdy found. A driver driving at 130 km/h (81 mph) would need to slow down by 33 km/h, to around 97 km/h (60 mph), in order to maintain the same energy consumption as when driving without any additional load, the study warned. Switching to a rear-mounted carrier resulted in a far less dramatic impact on efficiency, reducing it only slightly to 3.2 mi/kWh.