Is there a MPG rule of thumb when towing?

but have you now got an Adblue tank too? Maybe the smaller fuel tank is to make room for the Adblue tank ... 🤷‍♂️

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Ah! I'm fortunate that I still have a spare wheel in my ML's spare wheel well! 😊

I tow a 1200kg low profile pop-top with a 150bhp 1.5L petrol Audi A3.

Everyday solo driving is typically 45/50mpg, with high 60's mpg on a run. Towing is anything from 34/35mpg fully laden car and van at higher continental speeds to 40mpg on a good slower speed UK motorway run.

When looking closely at the figures returned I get about 2/3 rds towing what I would solo driving in a like for like manner.

Thinking back to previous 2L diesel Touran and Yeti with lower output engines the figures and fractions are very similar.

Colin

My experience over the years has always been that towing resulted in about 40 to 50% more fuel consumption on average, regardless of the car I happen to be using. I should add, however, that whatever outfit I have had, the weight of the caravan has always been at or close to the towload limit for the car, so my figure may not truly reflect what others might expect with a relatively lighter caravan.

Interesting discussion, I think the rule of thumb approach to economy is more important than anything else, specifically when towing.

Whilst many people slip into a style of driving that suits them when solo, and each individual gets a different mpg as a result, even using exactly the same car, the main reason for high mpg when the driver is taken out of the picture, is tyre pressures, road rolling and wind resistance, and the load.

Best address those before addressing your driving technique;

For example, how often does the average driver check their tyre pressures?  The recommended minimum is weekly, for emergency vehicles it's the start of every shift, but how often do you check them?  It's even more important your tyre pressures are correct on your outfit before it moves down the road, reducing rolling road resistance.

Secondly, rolling road resistance vs wind resistance; there's numerous studies that show that these both rise significantly at 56 mph, in calm conditions, so the general advice is that driving either solo or an outfit beyond 56 mph severely impacts fuel economy.

Thirdly, the heavier the load, the more energy is required to move it and stop it, so if you're more concerned about economy than comfort, then the lighter your outfit should be.

So tyre pressures, 56mph top speed, and no excess load.

Then you could have your engine remapped for economy (solo) or towing (outfit), incidentally with increase in the amount of torque at low revs (towing remap), you can also short shift a manual gearbox when driving solo to improve overall economy.

Finally, it's you, the driver that needs to change the way you drive, generally anyone that has undertaken LGV, Advanced Driving, or Emergency Driving in the past, will have vehicle sympathy, better hazard anticipation, better throttle/brake control, and appropriate gear selection that improves economy overall.

So for a car driver, undertaking any Advanced Driving Course and one of the Caravan Club Caravan or Motorhome Courses is a very good idea.  You'll be safer overall, and your economy should improve, and your car will last longer before needing brakes and tyres.

I get up to 65 mpg from a 2.0 Diesel Toyota Avensis Estate with a towing remap when driving solo, short shifting the 6 speed manual gearbox whenever the revs get to 1950 rpm.

I've only ever towed my caravan once when I bought it and moved it to my secure storage, but I will have to change my driving style even after that one trip, it needs more rpm between gear changes, the outfit slows down more significantly due to wind resistance requiring less braking pressure and more anticipation of the road ahead, and will require using 5th gear on single carriageway roads, and 56mph in 6th gear on Motorways and dual carriageways.

I think if economy is more important that your itinerary, then using a weather app to avoid headwinds, and studying your touring route to avoid steep inclines would be more of a priority.

So I'll be using the above as a 'Rule of Thumb', and my wife will determine our itinerary, and we'll suck it and see.

I'm guessing we have gremlins at work as another old thread has surfaced.

On another forum I've been following a similar thread/question. The findings seems to be:-

- diesel vehicles return about 60% of solo driving figures.

- petrol vehicles return about 50% of solo driving figures.

- the larger the tow vehicle engine the less the difference.

- the larger the vehicle profile, eg 4x4 as opposed to hatchback, the less the difference.

- driving at peak torque which is generally around 1950 rpm and typically 55/60mph is best.

 

Colin