Max speed when towing a trailer

PauSum

PauSum

Forum Member
Joined
Aug 1, 2008
Messages
321
Location
Perth Australia
Car Year
2005 and 2015
Car Model
Forester and Outback
Transmission
5 speed manual and 6 speed CVT
The manual of my MY14 2.0D CVT Outback indicates the following:
"Never exceed 80 km/h (50 mph) or legal towing speed limit, whichever is lower."

We plan to tow a trailer to Tasmania and it will take us a very long time to get there if we drive 80 km/h max for the whole trip - although I do not intend to drive too fast such as over 100 km/h (I haven't checked the legal speed of this as yet).

Just wondering has any diesel outback owner ever towed (trailer) over 80 km/hr?

Thank for sharing of your experience on this.
 
I've been on several trips where OBs and Fozs have towed fairly large camper trailers at legal highway speeds; I've never heard any complaints.
 
^ ditto.

I have towed my CT behind Roo2 at 100-110 kmh without the slightest problem.

Back when it was just a normal box trailer (7x4), I have towed it fully loaded at up to 130 kmh behind my 1.8L '93 Impreza many, many thousans of kms with no problems ...

And ditto behind my 1.4L Mitsubishi Colt, around 5-10,000 kms!
 
I suspect it's an donkey covering exercise by Subaru on the CVT,
towing generates a lot more heat in any box, and the CVT would be very particular.
I'd be investing in an external tranny cooler for any Auto/ CVT that does a lot of towing.

And also using any sport mode that may be available to control the shifts and hold it higher in the rpm.

I regularly tow my camper with my SH9 diesel, and it only ever sees top gear (6th) when running along the flat at 100 or light downhill
the engine itself is much happier to be kept cruising at 2000-2100 revs when pulling the weight.
 
The car itself can do it. Unfortunately here in the states we don't have this drive train package available so we have no experience with it. Maybe this combo the diesel is spinning the turbo constantly and it can overheat the pistons while towing a trailer?
 
being a Variable Geometry turbo aswell as a diesel it is making positive manifold pressure almost 100% of the time (except when the ECU closes the throttle butterfly to top-up the vacuum in the brake booster)
But given the inherent construction of a DIesel engine, they are designed for the extreme heat and pressure of diesel combustion.

One of the local Rally Teams even ran the 2010 Diesel Forester in a special "SUV Class"
only very limited modifications were allowable for that class of racing, wher it's running 30PSI of boost for long durations.

[ame="https://www.youtube.com/watch?v=DLtrHgkJ5Sg"]Subaru Forester Turbo Diesel Rally car Australian rally Championship 2012 Coffs Coast summary - YouTube[/ame]
 
Thanks everyone. I suspect the speed limitation is related to the (CVT) cooling issue as this is also stated in the manual:

"Diesel engine models only:
The vehicle speed may decrease when climbing up a slope or during continuous high-load driving while towing a trailer. Therefore, please use extra caution when climbing up slopes while towing a trailer (for example, never attempt to pass vehicles while driving uphill, etc.). This control system is necessary for maintaining the ability of the vehicle cooling performance and does not indicate a malfunction. The vehicle speed performance while towing a trailer will return to normal when the load of the vehicle is decreased and the cooling performance returns to normal."

Subaru Australia had responded to my query that there is no need to add extra cooler though.

"I can confirm that your vehicle does not require any transmission cooler to be added. Changes in the vehicle approximately 2010 onwards saw an improved and larger cooling system added to the transmission, which means the transmission in your vehicle can cope with towing a trailer up to its maximum limit."

Cheers
 
Gidday PS

I would be asking Subaru Australia why their advice is different from what is stated in the OM for your car!

Get it in writing ... :iconwink:
 
LOL: and so many think that Subaru towing ridiculousness is US-specific.

There are certain things that, I think, denote a small, uncertain company. Subaru was so laden with those till 2009-10 but the lack of clarity with regards to towing just keeps going and going.
 
Being the EE20 which is rated at 2tonne towing capacity I'd comfortably tow at the legal speed limit of 100kmhr. They are just covering their arses. If overtaking was needed and the trailer stable, conditions safe I'd happily accelerate past 140kmhr if needed.
 
My XT towing my Stockman Podtrailer was happy on 170km/h in the NT with no apparent increase in engine temp and just an extra healthy appetite for the go juice. Also wasn't being strained as it had plenty left - could have easily gone over the 200 mark- but still trying to pretend I was a responsible driver. And I knew from earlier experiences how stable the trailer is. I'd be more concerned at the speed rating for the trailer tyres.
 
Gidday Guzzla

Do bear in mind that the OP is talking about a diesel with a CVT, not a petrol engine with any kind of conventional auto or manual box ... :poke: :iconwink:.
 
I could add I've comfortably towed a laden trailer at 100kmh incl through the Black Spur (not 100kmh though haha) but as RB says this isnt about Subies in general its more about the CVT.

I would call Subaru back and ask for clarity on towing a trailer (mention the weight of trailer/load) and explain that an 80kmh limit on towing is both ridiculous & dangerous. I would not like to be sitting on 80 with semis banking up behind me and getting impatient!
 
So from a legal standpoint if something happened at speeds above 80km/hr and it can be proven you exceeded that speed, then anyone injured in the accident can sue
And the legal limits while towing are
NSW is signposted speed unless the combo weighs more then 4,500kgs then it 100km/hr but if your combo exceeds that then your in for a world of hurt if your car isn't GVM upgraded and you don't have an LR license anyway
WA is 100km/hr whilst towing

TAS is 90km/hr whilst towing

[EDIT] the above statement is no longer correct. See post by Robbks below re: Tas Road Rules 2015. [end edit]

 And all other states and territories are signposted limits
 
Last edited by a moderator:
BlakejMarshall said:
So from a legal standpoint if something happened at speeds above 80km/hr and it can be proven you exceeded that speed, then anyone injured in the accident can sue
And the legal limits while towing are
NSW is signposted speed unless the combo weighs more then 4,500kgs then it 100km/hr but if your combo exceeds that then your in for a world of hurt if your car isn't GVM upgraded and you don't have an LR license anyway
WA is 100km/hr whilst towing
TAS is 90km/hr whilst towing
And all other states and territories are signposted limits
Click to expand...


Tasmania does not state a towing limit in the 2015 updated road rules
As such, towing at the posted limit applies.

Please make sure any road safety information is 100% verified correct before posting.

https://www.transport.tas.gov.au/__...109566/Tasmanian_Road_Rules_2015_for_web1.pdf
 
Well I'll be!!

The only reason I knew that was I got booked doing 105 in a 100, but I had a trailer in tow so I got 15 over, that was in 2014 though
 
Robbks said:
Tasmania does not state a towing limit in the 2015 updated road rules
As such, towing at the posted limit applies.

Please make sure any road safety information is 100% verified correct before posting.

https://www.transport.tas.gov.au/__...109566/Tasmanian_Road_Rules_2015_for_web1.pdf
Click to expand...

Gidday Blake

I agree with what Rob has said. It is very important to try to get these things right!

I also think that State/Federal law overrides anything that a manufacturer advises in the Owners Manual.

The States nearly got together to fix the disparity in speed limits a few years ago. Victoria (of course ... ) would not agree to having standard 110 Kmh limits on the open road, but most other speed laws are now standard across all States and Territories. The 100 Kmh maximum on heavy vehicles was left in place, as it gives faster moving traffic a chance to pass without exceeding the posted limit on the open road - everywhere except Victoria, of course ... :poke: :puke:.
 
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