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Discussion Starter · #1 ·
Hi All,

First time poster, and relative newbie to towing.

Just running these calculations by someone else. We're going camping soon and I want to be sure I'm correct.

  • Unbraked - 550kg per Australian manual
  • Tare weight of trailer is 300kg (meaning I can only load up to 250kg into the trailer)
  • Tow bar load is 120kg (meaning I can tow up to 1,200kg, although of course I can't given the trailer I have is unbraked)
  • Kerb weight of car is 1,524kg

I actually can't find a Gross Combination Vehicle Mass figure for the car, but let's estimate 180kg of humans (two adults, two kids) and 400kg of camping gear spread across the car and the trailer.

That should be fine for the 6 yeah?

Thanks all,
Andrew

I actually can't find
 

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400kg of camping gear spread across the car and the trailer.
400 kg = almost 900 lbs.

Just out of curiosity, what on earth are you bringing camping that weighs 900 lbs?! Pack lighter, man! 馃槅

In all seriousness, load capacity can normally be found on the tire information placard in the driver鈥檚 door sill or in the owner鈥檚 manual, if that's what you're asking. I haven't done the math, but 4 humans, a trailer, and a whopping 900 lbs. of camping gear sounds like it would be well over the safe limit.
 
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400 kg = almost 900 lbs.

Just out of curiosity, what on earth are you bringing camping that weighs 900 lbs?! Pack lighter, man! 馃槅
I think they need a cast iron kitchen sink.
 

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Hi All,

First time poster, and relative newbie to towing.

Just running these calculations by someone else. We're going camping soon and I want to be sure I'm correct.

  • Unbraked - 550kg per Australian manual
  • Tare weight of trailer is 300kg (meaning I can only load up to 250kg into the trailer)
  • Tow bar load is 120kg (meaning I can tow up to 1,200kg, although of course I can't given the trailer I have is unbraked)
  • Kerb weight of car is 1,524kg

I actually can't find a Gross Combination Vehicle Mass figure for the car, but let's estimate 180kg of humans (two adults, two kids) and 400kg of camping gear spread across the car and the trailer.

That should be fine for the 6 yeah?

Thanks all,
Andrew

I actually can't find
I am not sure... but I think the wagon, in Australia, is solely an automatic? It may be 2.0 litres, or 2.5 litres Skyactiv-G or 2.2 litres Skyactive-D?

Regardless of the engine size/type, if it is an automatic, and notwithstanding the Australian owner's manual showing 550kg unbraked - be aware that the stock automatic has a heat exchanger with the engine coolant, and while this is an efficient way of cooling the automatic - it i) results in the automatic transmission fluid going to above 230F / 110 Celsius when under load... (and possibly to 240F / 115 Celsius). This is pretty high, even if the ATF is fully synthetic. Elastomers suffer at these high temps regardless of synthetic or otherwise; and ii) the design of the heat exchanger for the ATF - places the exchanger right on the case of the transaxle. A special edge-drilled aluminum plate would have to be fabricated to be able to plumb-in a conventional air-to-ATF aux. cooler, which would be able to lower ATF max temps to a more reasonable 195F - 205F.

So what I am saying, is that if your car is an Automatic - then (stock) it really is not a great tow vehicle (if you care about the A/T's longevity). Go easy on it, particularly if your vacation area has hills.

PS... I would absolutely LOVE to be able to get an Australian market tow-bar. The most subtle / hidden and high capacity one I could find anywhere... and thoroughly fatigue-tested by the vendor who developed it for Mazda Australia.
 

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Discussion Starter · #5 ·
Thanks all.

And yeah, re-reading this, 400kg seems crazy!

However when big family canvas tents weigh 60 odd kg, it does add up quickly.

Thanks for the warning re: transmission. Will keep an eye on it. I am well within the limits of the car so hopefully all will be well. I can put it in the manual mode to go up hills.

Finally, there is no GVM information in the manual. I even rang Mazda and the RMS (our roads regulator), and the latter was more helpful than the former in estimating my GVM.

A
 

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  • Unbraked - 550kg per Australian manual
  • Tare weight of trailer is 300kg (meaning I can only load up to 250kg into the trailer)
  • Tow bar load is 120kg (meaning I can tow up to 1,200kg, although of course I can't given the trailer I have is unbraked)
  • Kerb weight of car is 1,524kg

I actually can't find a Gross Combination Vehicle Mass figure for the car, but let's estimate 180kg of humans (two adults, two kids) and 400kg of camping gear spread across the car and the trailer.
What engine and transmission do you have? If your manual is like the European manuals, look for a towing weights table in section 5.

I don't have any copies of the Aussie manual; only European manuals. Those cover most of the Mazda-buying world except North America, Australia, and New Zealand.

In those, tow ratings generally are limited to pretty close to these figures for up to 12% grades:

Skyactive-G 2.0 and 2.5: 680kg for trailers without brakes, 1500kg for trailers with brakes, and gross combination weights are generally limited to ~3500kg assuming trailers with brakes.

Skyactive-D 2.2: 730kg for trailers without brakes, 1600kg for trailers with brakes, and gross combination weights are 3690 to 3750kg depending upon factors not specified.

WARNING: THE BELOW IS SPECULATIVE AND USES SIMPLE ARITHMETIC AND ASSUMPTIONS, AND IS FOR EDUCATIONAL PURPOSES ONLY. YOU MUST NOT RELY ON THIS FOR LOADING YOUR CAR, BECAUSE I HAVE NO IDEA WHETHER THIS IS RATED OR REASONABLE IN YOUR MARKET.

If we reduce the European table's combined weights by the difference between trailers with brakes in Europe and without brakes in YOUR market (so 1500 - 550 or 1600 - 550), we get ~2550kg combined for the gasoline engines, and 2640 - 2700kg combined for the diesels.

From your post, if your car is 1524kg plus 180kg of people you're at 1704. Add 550 for a fully-loaded trailer and you're at 2254kg. That implies another ~296kg of cargo carrying capacity if you have a gasoline engine, or another 386 - 446kg if you have a diesel.

These numbers are very approximately the same as the North American gross vehicle weight ratings of ~1945kg for the 2.5 and automatic transmission sedans. Still, I'm not comfortable saying you should load your car this way.
(-:
 

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... thanks for the warning re: transmission. Will keep an eye on it. I am well within the limits of the car so hopefully all will be well. I can put it in the manual mode to go up hills.
...
Yeah, I guess if you can control whether the transaxle's torque converter is locked-up versus slipping you could control the max temps. And you rightly point out that manually selecting a lower gear theoretically would allow you to keep the torque converter locked-up.
 

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Discussion Starter · #8 ·
What engine and transmission do you have? If your manual is like the European manuals, look for a towing weights table in section 5.

I don't have any copies of the Aussie manual; only European manuals. Those cover most of the Mazda-buying world except North America, Australia, and New Zealand.

In those, tow ratings generally are limited to pretty close to these figures for up to 12% grades:

Skyactive-G 2.0 and 2.5: 680kg for trailers without brakes, 1500kg for trailers with brakes, and gross combination weights are generally limited to ~3500kg assuming trailers with brakes.

Skyactive-D 2.2: 730kg for trailers without brakes, 1600kg for trailers with brakes, and gross combination weights are 3690 to 3750kg depending upon factors not specified.

WARNING: THE BELOW IS SPECULATIVE AND USES SIMPLE ARITHMETIC AND ASSUMPTIONS, AND IS FOR EDUCATIONAL PURPOSES ONLY. YOU MUST NOT RELY ON THIS FOR LOADING YOUR CAR, BECAUSE I HAVE NO IDEA WHETHER THIS IS RATED OR REASONABLE IN YOUR MARKET.

If we reduce the European table's combined weights by the difference between trailers with brakes in Europe and without brakes in YOUR market (so 1500 - 550 or 1600 - 550), we get ~2550kg combined for the gasoline engines, and 2640 - 2700kg combined for the diesels.

From your post, if your car is 1524kg plus 180kg of people you're at 1704. Add 550 for a fully-loaded trailer and you're at 2254kg. That implies another ~296kg of cargo carrying capacity if you have a gasoline engine, or another 386 - 446kg if you have a diesel.

These numbers are very approximately the same as the North American gross vehicle weight ratings of ~1945kg for the 2.5 and automatic transmission sedans. Still, I'm not comfortable saying you should load your car this way.
(-:
Thank you mate, that's really helpful.

The engine is the petrol variant, 2.5L. Transmission is the six speed auto, with manual mode (paddle shifters).

I've attached the tow information from the manual. You will note that the tow limits on the AU car is 550kg, whereas per above it's 680kg in Europe.

Your numbers are pretty close to what I've come up with. They are different, but still enough to give me peace about it.

Since posting this thread, I've been in touch with our regulatory body here in AU (the RMS). Mazda could not provide me with a Gross Vehicle Mass (GVM - the total load the car, without trailer, can take). The RMS didn't have the figure either, but it's basically a formula - Kerb Weight (1,524) + 68kg per seat and 13.6kg of luggage per seat. This gives me a GVM of $1,524 + 408 = $1,932. This is the maximum the car will take (leaving aside the trailer) in AU, not far from the US numbers.

If I then load in the trailer at 550kg, then I'm at circa 2,480kg, closely aligned with your calc above.

If you then remove the trailer again, you're back to circa 1,930. Remove the kerb weight and the weight of my humans = 228kg is the remaining pay load I can load into the Mazda. Even though our numbers don't fully agree (and funnily enough, I have had three smarter people than me give me different answers today), mines on the lower end of payload so feel comfortable with that.

Happy (and encourage you to) for you to challenge my numbers.

Thanks legend,
Andrew
 

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There is a sticker on the door jam (usually left side, but might be on right on RHD cars) that will state the Gross Vehicle Weight Rating (GVWR), it has to be on every car produced. It will also have the tire rating and inflation specs.
 

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The terminology you're using in Australia is different than here in US however it appears none of these above estimates are taking the tongue weight of the trailer, only the total (towed) weight of the trailer.

The tongue weight of the trailer is the weight carried on the hitch ball when the trailer is loaded and level. THE TONGUE WEIGHT MUST BE SUBTRACTED FROM THE GROSS CAPACITY OF YOUR CAR.

Also advise checking the total load capacity of your tires and wheels. If tires are similar to US-spec tires, the load rating is embossed on the sidewall. Vehicles that aren't specifically intended for towing don't have much excess load capacity.

Be safe.
 

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it appears none of these above estimates are taking the tongue weight of the trailer, only the total (towed) weight of the trailer.
That鈥檚 not quite true. While I agree with your general reminder to think about the weight carried by the car vs the trailer axles, that鈥檚 a matter of where weight is placed, not a matter of the total amount of weight.

Also advise checking the total load capacity of your tires and wheels.

Be safe.
I agree with this concept, too, though one should reasonably expect Mazda to have selected appropriate tires and wheels for a vehicle they explicitly rate for towing. Remember that the 6 is rated to tow in (nearly?) every market in the world except North America.
 

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Thank you mate, that's really helpful.

The engine is the petrol variant, 2.5L. Transmission is the six speed auto, with manual mode (paddle shifters).

I've attached the tow information from the manual. You will note that the tow limits on the AU car is 550kg, whereas per above it's 680kg in Europe.

Your numbers are pretty close to what I've come up with. They are different, but still enough to give me peace about it.

Since posting this thread, I've been in touch with our regulatory body here in AU (the RMS). Mazda could not provide me with a Gross Vehicle Mass (GVM - the total load the car, without trailer, can take). The RMS didn't have the figure either, but it's basically a formula - Kerb Weight (1,524) + 68kg per seat and 13.6kg of luggage per seat. This gives me a GVM of $1,524 + 408 = $1,932. This is the maximum the car will take (leaving aside the trailer) in AU, not far from the US numbers.

If I then load in the trailer at 550kg, then I'm at circa 2,480kg, closely aligned with your calc above.

If you then remove the trailer again, you're back to circa 1,930. Remove the kerb weight and the weight of my humans = 228kg is the remaining pay load I can load into the Mazda. Even though our numbers don't fully agree (and funnily enough, I have had three smarter people than me give me different answers today), mines on the lower end of payload so feel comfortable with that.

Happy (and encourage you to) for you to challenge my numbers.

Thanks legend,
Andrew
Glad to share what little info I have. I cannot challenge your figures, and the way you鈥檙e going about it makes sense to me. I think if I was in your place I鈥檇 move ahead with the info you have. Well done contacting both Mazda and the Australian regulatory agency to try to get the info you need!

Cheers and best wishes.
 

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This is only partially true:

That鈥檚 not quite true. While I agree with your general reminder to think about the weight carried by the car vs the trailer axles, that鈥檚 a matter of where weight is placed, not a matter of the total amount of weight.
Theoretically, you could put enough weight behind the trailer axle to create negative tongue weight which some might think makes them "safe" from exceeding the car's gross capacity. Generally the tongue weight should be between 10-15% of the trailer's gross weight in order to prevent excessive fishtailing.

I agree with this concept, too, though one should reasonably expect Mazda to have selected appropriate tires and wheels for a vehicle they explicitly rate for towing. Remember that the 6 is rated to tow in (nearly?) every market in the world except North America.
Mazda certainly designed and equipped the vehicle with properly rated wheels and tires, but people buy new wheels and tires. Stylish aftermarket wheels don't always meet the same load capacity of the OEM wheels and replacement tires aren't always the same load rating as the OEM tires.

The OP is looking to stay safe and there are lots of factors to consider when using a passenger vehicle especially when approaching the limits for safe operation. This thread only scratches the surface.
 

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Discussion Starter · #15 · (Edited)
The terminology you're using in Australia is different than here in US however it appears none of these above estimates are taking the tongue weight of the trailer, only the total (towed) weight of the trailer.

The tongue weight of the trailer is the weight carried on the hitch ball when the trailer is loaded and level. THE TONGUE WEIGHT MUST BE SUBTRACTED FROM THE GROSS CAPACITY OF YOUR CAR.

Also advise checking the total load capacity of your tires and wheels. If tires are similar to US-spec tires, the load rating is embossed on the sidewall. Vehicles that aren't specifically intended for towing don't have much excess load capacity.

Be safe.
This is correct, and widely estimated at 10% of the total weight of the trainer (net) + cargo.

Thanks for pointing that out.
 

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Discussion Starter · #16 ·
This is only partially true:



Theoretically, you could put enough weight behind the trailer axle to create negative tongue weight which some might think makes them "safe" from exceeding the car's gross capacity. Generally the tongue weight should be between 10-15% of the trailer's gross weight in order to prevent excessive fishtailing.


Mazda certainly designed and equipped the vehicle with properly rated wheels and tires, but people buy new wheels and tires. Stylish aftermarket wheels don't always meet the same load capacity of the OEM wheels and replacement tires aren't always the same load rating as the OEM tires.

The OP is looking to stay safe and there are lots of factors to consider when using a passenger vehicle especially when approaching the limits for safe operation. This thread only scratches the surface.
Thanks mate.

Tyres and rims are standard Mazda.

Car is also being serviced today by Mazda, and including a wheel balance and alignment for extra safety (#safetysam)
 

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Theoretically, you could put enough weight behind the trailer axle to create negative tongue weight which some might think makes them "safe" from exceeding the car's gross capacity. Generally the tongue weight should be between 10-15% of the trailer's gross weight in order to prevent excessive fishtailing.
That's still a matter of where the weight is, and OP has demonstrated good awareness of these kinds of issues. He's gone to Mazda and to his national regulatory authority to figure this stuff out.

Too, tongue weight percentage requirements or recommendations differ in different parts of the world, because the general approach to towing and tow vehicle and trailer design differ. While 10 - 15% is the North American norm, most parts of the world use a lower percentage standard. N. America generally wants more tongue weight, often lower total weight, and tends to not reduce speed vs what much of the rest of the world does. The rest of the world tends to use less tongue weight (percentage-wise), allow higher total weight, and require reduced speeds. Either higher tongue weight OR lower travel speed improves stability. It's simply a choice of posture or approach to the issue. Since OP is in Australia, I choose to not instruct him as to N. American tongue weight recommendations.
 
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That's still a matter of where the weight is, and OP has demonstrated good awareness of these kinds of issues. He's gone to Mazda and to his national regulatory authority to figure this stuff out.

Too, tongue weight percentage requirements or recommendations differ in different parts of the world, because the general approach to towing and tow vehicle and trailer design differ. While 10 - 15% is the North American norm, most parts of the world use a lower percentage standard. N. America generally wants more tongue weight, often lower total weight, and tends to not reduce speed vs what much of the rest of the world does. The rest of the world tends to use less tongue weight (percentage-wise), allow higher total weight, and require reduced speeds. Either higher tongue weight OR lower travel speed improves stability. It's simply a choice of posture or approach to the issue. Since OP is in Australia, I choose to not instruct him as to N. American tongue weight recommendations.
Your response shows a pretty astute understanding of towing technology, from my point of view. Great info.
 

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Discussion Starter · #19 ·
Hi all,

Just closing off this discussion.

  • The wagon did well towing 550kg. I went very gingerly to the campsite, but returned with much more confidence.
  • The biggest concern was not the power or braking capacity or even payload, but the fact that a relatively high riding trailer, when coupled with a low running vehicle, meant the combined vehicle did dip in the middle. No scrapping or anything like that, but just went really slow over bumps. I was also concerned for a while with the rear wheel arch and the gap between the tyre, but all went well.
  • Fuel economy in AU is shown as how many litres per 100km. The trip returned 9.9L/100K, which is about what I get for city driving. If I wasn't towing the trailer, I would have expected about 7.5/100
  • The transmission was fine - only a couple of times did the transmission kick into 3rd on a hill, otherwise it was comfortable in 4th or 5th.

I weighed EVERYTHING I put in the car / trailer, and in luggage alone, I had nearly 300kg! Adding in the tow ball load, the trailer weight and 4 passengers, I was at circa 80% of payload recommendations (which I think are really conservative).

One thing I learnt is this - you must include the tow ball load in your vehicle payload. This is something people forget all the time.

I also had a number of people comment about how good looking my white 2016 GT wagon is. I think it's hard to find a better looking wagon in the AU market, besides maybe some of the Merc AMGs .

Anyway, go well Mazda peeps.

Andrew
 

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I know this thread is older, but thought I'd add a link to an interesting video here for posterity's sake. The discussion above has context which constrains or bounds the words we used. The video violates some of those bounds for illustrative purposes. I think that's a useful addition to towing weight and weight distribution discussions, and underscores how the previous discussion stays within the implied (or indirectly stated) bounds.

P.S. I find the narrator oddly irritating because he never pronounces the voiceless fricative "th." Instead, he replaces it with the "f" fricative. I don't know why that kinda bugs me, but it does.

 
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