Toyota read this - what's my prime thought?

Or you can make lemonade out of the lemon storage space:
2016 Toyota Prius can tow a 1,600-pound trailer, for some reason

It seems you can tow up to 1,600 lbs in the Gen 4 because of the advanced cooling. Maybe they are not making it known in the US because, well, we get carried away.

 

Very few cars have a tow rating in the US, even if they do in other markets. The US manual for the 2016 Prius even discourages using a hitch mounted bike rack.

 

Even Toyota's RAV4 hybrid which is actually designed to tow, can only tow a rated 1,750 lbs. Maybe our litigious nature in the states is preventing many advances we see in other countries. After all not many other countries have patrons who sue Starbucks because they put too much ice in their ice coffee.

 

Lawsuits might be part of it, but cars had tow ratings in the past.
The standard the manufacturers have promised to use for truck tow ratings is probably harder than what is used for European cars.
Then with cheap fuel, upselling a truck to someone that needs to tow is a little easier.

Before the new Prius, the only hybrids Toyota put a tow rating on had AWD. In the case of the RX/Highlander it was still lower than the ICE model.

 

maybe we force longer warranties on manufacturers than other countries.

 

Europeans also tend to have much less tongue weight (looks like 4-7% is recommended there, as opposed to around 10-15% here) relative to their trailer weight, to reduce GVWR impact of the trailer on the car, and the resultant stress on the rear suspension and the lift on the front wheels. This affects handling adversely, though, which is compensated for by lower speed limits when towing - in many European countries, hitching up a trailer reduces speed limits - even on freeways - to as low as 80 km/h (50 mph). Some countries (looks like Belgium) allow as much as 120 km/h while towing, though, as long as the combo of car and trailer loaded are under 3500 kg (which you won't exceed with a Prius). And, there's license restrictions on trailers over 750 kg there (although Toyota isn't quite allowing 750 kg).

That said, Toyota's allowing 75 kg of vertical coupling load (read: tongue weight) on the Prius hitches that they're selling in Europe, which at the 725 kg limit would be 10.3% tongue weight, so I'm thinking the 725 kg limit is mainly due to braking performance (due to 750 kg and lower trailers not being required to have brakes in Europe, mandating that a lower weight trailer have them to use it isn't going to go over well), and possibly cooling.

As far as warranties, yeah, no, we don't force anything there compared to Europe, typically.

Plus, there's the liability impact. At the much lower speeds of European trailers in most countries, with stricter licensing standards, automakers don't have to worry about negligence as much - if someone's towing at American speeds, they're the ones liable, not the automaker. Here, if you said "keep it under 50 mph for this tow rating to be valid", that wouldn't fly, because everyone knows a 50 mph speed limit while towing isn't workable here. So, tow ratings are lower, and exceeding the tow ratings risks getting a lawsuit for negligence. Good news is, from Googling around, doesn't seem like insurance companies usually refuse claims for exceeding tow ratings (especially zero pound tow ratings), but you might get found at fault by insurance companies even if you're not, and you might get your coverage dropped after the claim is paid out.

Finally, we don't know that the Prime would have the same tow rating in Europe. I'm guessing it won't - all the additional battery weight is over the rear suspension.

And, most of the cars that had high towing capacities in the US were body-on-frame RWD V8 cars, which are basically trucks anyway, just lower. (That said, with the SUV boom, the Crown Vic did lose most of its tow rating... so some of it was intended to push people into SUVs and pickups.)

tl;dr: It's because of tongue weights typically being lower (less stress on the vehicle), and towing speeds typically being far lower (less stress on the vehicle, less braking demand, less worry about the lower tongue weights reducing stability). I would keep trailers on a US Prius under 500 kg (1102 lbs) so that 15% tongue weight is 75 kg (165 lbs), and keep speeds down.

 

Our 2001 Sable is rated for 1600lbs with a basically empty car.
The pre-cheat TDI Jettas had a 2000lbs one.
Within the past year, the Volvo site was still claiming 3300lbs for their models.
I'm considering using the Sonic for towing. For anything heavier than a light utility trailer, I'd use trailer brakes.

 

i don't think anyone in the world gets 10/150 outside of carb. even 8/100 is unusual.

 

7 Automakers With The Best Car Warranties | Bankrate.com
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The hybrid warranty is actually the emission system warranty. It covers the hybrid battery, because it is essential in providing the car's low smog rating. It does not cover the motors or inverter. The 8yr/100k mile warranty is federally mandated on all cars. The 10yr/150k mile is an option to the manufacturer in CARB states, but they lose out on incentives to sell the car if they opt out.

I don't see how towing could prematurely kill a catalytic converter. It might kill a hybrid battery faster, if the system didn't have effective protections for the battery to begin with, but with towing, it is the transaxle, motors, inverter, ICE, brakes, and frame that will see the extra stress of doing so.

The new Prius can tow because it appears Toyota has improved the transaxle cooling. I now think it could have had a tow rating earlier if Toyota had gone with a more robust oil for the transaxle. It is filled with an automatic transmission fluid, which has to pull double duty as a lubricant and hydraulic fluid. With those requirements means the fluid is more readily degraded by higher temperatures than motor oil. The transaxle isn't an automatic transmission though; there are no clutches or torque converter that require a hydraulic fluid to operate. A fluid for a manual transmission might have been a better choice; some older ones call for motor oil. These can generally handle higher temperatures.

I suspect Toyota went with an ATF because their standard fluid for manuals was thicker, and would decrease drivetrain efficiency. A hybrid specific fluid would have increased costs while hybrids were new. Perhaps part of the improvement is a hybrid specific fluid; now that Toyota has a near full line up of hybrid models.

I agree the Prime likely won't have a tow rating. It's already too heavy for a fifth seat.

 

We have a least one Gen2/3 guy towing I think he may have had to beef up his cooling system. Sounds like the UK message was a subliminal message to the USA? Maybe get some use of that capability here by some anyways.

 

our '06 SUV hybrid (Lexus) had a recall for overheating /towing. IIRC, it said they needed to reprogram controllers for the liquid cooled inverter. 10+ yrs now ... same traction pack & running strong. I don't recall what the tow rating is, but I'm sure over the years we pushed it past the limit. Still averaging over 29 MPG.
MAN i wish it had a plugin version. There IS one aftermarket company ...
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i think the reason for no towing in usa vs elsewhere is more tactical than mechanical. if not battery warranty (which i think it may be) than something else.

 

Adding a transmission cooler for an automatic for towing is a common recommendation. If it isn't already standard equipment, it is part of a tow package on trucks and SUVs.

 

considering most of UK temps - i'd be hard pressed to worry about high towing temp's



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It's worth noting that that 725 kg tow rating applies Europe-wide, though, and there's much hotter areas than the UK.

 

Towing is one thing, braking is another.

Having owned a diesel 2500 truck pulling a 5th wheel, I came to appreciate trailer brakes. I can't imagine pulling a trailer in a Prius without trailer brakes and all the associated wiring and controllers.

 

As I understand, electric brake controllers are not at all popular in Europe, but surge brakes are popular. So, the vehicle's initial braking causes the trailer to shift forward and apply its own hydraulic brakes using its own weight.

They then use a lockout when in reverse, to make sure that the trailer's brakes don't apply.

 

Was reading up on surge brakes, and some models of drum brakes will apply 20% while in reverse. I guess if you want some control backing down a steep incline.