Boat trailering

<div class='quotetop'>QUOTE(andyprius @ Dec 6 2006, 11:05 PM) [snapback]358733[/snapback]</div>

I expect that as long as you don't need VSC you won't be in trouble. My guess is that the traction and stability systems are not designed to have 400 lbs of momentum pushing from behind the car. It isn't just about tongue weight or total weight.

- Tom

 

I still really wouldn't...

 

I do it all the time. I tow a 200 pound shifter kart on a 200 pound trailer, and although it does drop the mileage about 20 percent the car really doesn't have much trouble pulling it at all. I don't notice any handling issues at all, the car is still easy to control. I'd recommend the Curt or Da'Lan Hitches. I'd also recommend using a Draw-Tite "Modulite" lighting adapter #18176. This unit totally isolates the trailer lighting from the car's wiring. I tried one of the basic wiring adapters they sell at Checker and found that the brake lights glowed dimly when the turn signals flashed, and the emergency flashers became intermittent.

 

I wouldn't do it. Get another car that doesn't have a recommended towing capacity of 0 lbs.

 

<div class='quotetop'>QUOTE(narf @ Dec 9 2006, 12:52 PM) [snapback]359756[/snapback]</div>

Hopefully you never have any problems with the transmission or the driveline, Toyota will certainly void the warranty if they find out you use the vehicle to tow.

The problem is not that you'd have issues immediately, I'd be concerned about the strain on the drivetrain and the effect of bolting a hitch to a unibody frame that is not designed to handle the weight dragging around behind the car.

Might not have an issue now, but 10 years from now? I wouldn't even consider towning ANYTHING with a Prius.

 

<div class='quotetop'>QUOTE(SW03ES @ Dec 9 2006, 09:19 PM) [snapback]359947[/snapback]</div>

I'm not sure why people feel the need to scold anyone who uses a Prius for anything other than drving slowly to grandma's house while pulse and glidiing. Let's actually think about this instead of having a kneejerk reaction.

First, I am driving the car at well under the rated load capacity when I pull a 400 pound trailer. What's the load rating, 800 some pounds, right? Plus, most of that load is supported by the extra two wheels of the trailer. The car's suspension only sees about 40 pounds of the trailer. There is some added aerodynamic drag and frictional losses from the trailer wheels, but those aren't beyond what the car can handle.
A good measure of how hard the car is working is what happens to the mileage. On this weeks trip from Denver to Colorado Springs and back while towing I averaged 40 MPG. That trip includes multiple 2000 foot altitude changes, all of which the car handled easily. The car couldn't have been working that hard and still gotten 40 MPG. As I figure it, the car is working about as hard as it would if it were driving without a trailer at 85 MPH.

The forces that drive the car are generated by the car itself and controlled by the car's computer based on inputs from the driver and the outside world. The car is unlikely to be able to generate motive forces that will damage the drivetrain, and a 400 pound trailer is unlikely to overwhelm the controls of a 2800 pound car. By the way, the trailer hitch itself mounts to bolts that hold the tie down hooks on the rear of the car. These hooks bolt into one of the strongest box sections of the frame, and these tie down hooks are designed to secure the car during shipping. It should be able to handlle the load of a light trailer without issues.

The last car I pulled this 400 pound trailer with was a 1992 Miata. It said right in the owners manual that the car was not recommended for towing. When I sold the car with 150,000 miles on it there were no problems with the engine, drivetrain, or transmission.

 

<div class='quotetop'>QUOTE(narf @ Dec 12 2006, 08:03 PM) [snapback]361319[/snapback]</div>

I still wouldn't do it. If Toyota thought it'd be ok, they'd have given it a non-zero recommended towing capacity. You need to think about the worst cases that a car might encounter by itself and what a trailer adds. Being under maximum cargo + passenger weight doesn't mean it's safe to use the remainder for towing. Think about the forces that would be encountered in crosswinds (there's a bigger cross section now and the trailer could be whipped around), when going over big bumps and dips, and extreme handling. How about a climbing a steep hill w/a varying headwinds along w/crosswinds? The tires on the Prius are rather narrow too, meaning not a very large contact patch.

The car is tied down by more than the rear during shipping and the car isn't under its own power at that point.

My 350Z has a max cargo + passenger weight of 450 lbs (it's only a 2 seater). Max towing weight is 1000 lbs. The convertible version I believe has similar/same maximum cargo weight limit yet the it specifically says "Do not tow a trailer w/your vehicle" in the manual presumably due to the convertible weighing more and having less rigidity.

I agree w/SW03ES w/respect to warranty. Towing a trailer would be considered abuse.

 

Personaly, I wouldn't tow anything with my Prius, but I also have three other vehicles that are much more capable for towing (two SUVs and a full-size pickup).

In a vehicle with a conventional drivetrain my main concern would be the transmission. One of my SUVs is a minivan-based crossover, and its drivetrain really isn't designed for towing, even though it's rated to tow 4500 lbs. However, the warranty is void if you tow anything unless you also install a power steering cooler and a transmission cooler. That tells me the design is pretty marginal for towing. Sure enough, early years of this vehicle had numerous transmission failures due to insufficient cooling, finally resulting in a class action lawsuit. Mine was built after the transmision was redesigned and thankfully has been problem free (so far).

The other thing to consider is aerodynamic drag. The same crossover SUV is only rated to tow 4500lbs if it's a boat. Trailer towing is limited to 3500lbs due to the greater aerodynamic drag. Probably not an issue for something low with minimal frontal area, but it could be significant if the trailer has more frontal area than the towing vehicle.

I doubt there is anyone reading this thread who is really qualified to comment on how durable the Prius powertrain is when it comes to trailer towing. For that reason, I'd err on the cautious side.

 

I would guess that the lack of towing capacity for the Prius has a lot more to do with lawyers than safety. The same reason the Nav system programming and radio data are disabled whenever the car is in motion. It's the fear that some clueless individual will will hitch up an Airstream to his Prius, and the car will go off a cliff somewhere. We don't want to get sued, better put a note in the manual about it.

I put more strain on the car when pulling onto the highway with a few passengers than I do cruising at 65 pulling a 400 pound trailer. This is a trailer that I can move around with one hand. It presents a pretty low cross sectional area to the wind. I've driven it in cross winds, it makes virtually no difference to the handling of the car.

 

<div class='quotetop'>QUOTE(narf @ Dec 13 2006, 12:25 PM) [snapback]361581[/snapback]</div>

I doubt this very much. Most other Toyotas are listed with a towing capacity. The Yaris for example has something like a 400 lb unbraked capacity.

As I posted earlier, the limitation is much more likely because of the VSC and/or traction control setup. They just haven't allowed for the momentum to be coming from behind the car rather than inside. With all the other engineering and test for a breakthrough car like this, it probably was decided that it was something that could be skipped until a later release.

- Tom

 

Your choice. You're obviously not interested in any of our viewpoints so all we can do is wish you luck.

To everyone else, don't use your Prius to tow. Toyota doesn't reccomend against it for no reason.

 

Something else to consider: Given how much the Prius wanders in strong cross-winds, it would be that much worse while towing that sailboat. The hull of that boat is about as long as a Prius, isn't it? That's got to put a pretty decent sideways push on the back of the car in a strong cross-wind gust.

[Edit: I see this was already mentioned. Nevermind.]

 

I tow and monitor all the temps of the MG's and the inverter and notice very little difference between non tow and tow. The only thing I notice is the milage hit. On a 10% grade down hill I notice a slight increase in the regen amps that's all. One PC member towed a small trailer across America and back without problems. People with Honda Insite's tow as well. This whole topic was thourghly discussed here about 2 1/2 years ago. If people were having drive train faliures I'm sure it would have come up.

 

Would those who tow with a Prius please post pictures of what you are towing? Thanks!

 

<div class='quotetop'>QUOTE(ilusnforc @ Mar 21 2007, 06:24 PM) [snapback]409841[/snapback]</div>

Here's a pic of my Prius towing my 16' aluminum riverboat with a 50hp outboard jet. I've had no problems, but I am blessed with not having to go very far or very fast to get to a boat launch. I don't have to drive in heavy traffic either. (You're all welcome to come visit our beautiful Lower Wisconsin State Riverway and I'll be glad to show you around!)

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