I tow a caravan up around 2900 kg with my XTR 2017 Mazda BT-50 2 two-door Freestyle-cab 4×4 3.2 litre. I generally tow in Sport mode on the open road in fifth gear at 90 to 100 km/h and it does it easily, my question is, am I towing in the correct manner, and since I tow in a lower gear would the next size up tyres aid me in any way?
Opinions are divided on this subject, Steve, but there’s a school of thought that says you shouldn’t tow anything heavy in an overdrive gear. Manual-gearbox Toyota LandCruisers of the last 30 years or so are prime examples of this, and hauling a heavy load in fifth gear in these can destroy a gearbox real quick. But all vehicles will be better off with overdrive locked out while towing; it’s just kinder to the driveline. So, your decision to tow in fifth gear rather than sixth is a sound one.
The only catch with some vehicles is that both fifth and sixth gears are overdriven. But fifth gear in the BT-50’s automatic gearbox is not, it’s 1:1, so you should be fine as long as you don’t exceed the manufacturer’s towing limits at any stage.
As for putting bigger wheels and tyres on the BT-50, you’d actually be altering the gearing, making it taller, which means the vehicle may not cover ground as effortlessly as it does now. Hills and headwinds might require more throttle, too, and that will mean higher fuel consumption.