Trailer Towing Tongue Weight
February 16, 2017 10:18 AM   Subscribe

I've never towed anything before, but we're thinking of getting a very small travel trailer. According to the owner's manual, the towing capacity of my car is 3500lbs but the maximum tongue weight is only 150 lbs. Almost every reference I've seen from the US says it's unsafe for tongue weight to be less than 10% of the total trailer weight. The car is German, is this just a difference between US standards and Euro standards? Would it still be safe but just at a reduced max speed?
posted by hwyengr to Travel & Transportation (10 answers total) 1 user marked this as a favorite
Does the car already have a hitch? Because different hitches can handle different ratios.

It's possible the max tow weight is assuming the highest rated hitch and a trailer with at least two axles. Trailer design also affects the tongue weight ratio.

Here's a pamphlet on towing, including tongue weight considerations, from the NHTSA.

Don't underload your tongue attempting to cut corners or tow more weight. Bad things will happen.
posted by SaltySalticid at 10:47 AM on February 16, 2017 [4 favorites]

How much does the fully loaded trailer weigh? If it's under 1,500 pounds then 150 lb tongue weight will be more than 10% and you'll be fine.
posted by Bruce H. at 10:51 AM on February 16, 2017 [2 favorites]

I'm guessing the towing capacity is based on the powertrain's ability, while the tongue weight limit is based on the hitch's rated strength. This is why people install aftermarket hitches.

(On preview: yep.)

The 10%-of-trailer-weight-on-the-tongue guideline is to prevent trailer sway, which is especially dangerous at high speeds, but I don't think it's safe to just drive around slowly with a tail-heavy trailer. The percentage may be different for multi-axle trailers.
posted by lozierj at 10:53 AM on February 16, 2017 [2 favorites]

A couple words of warning about tail-heavy trailers:

Trailer sway often strikes without warning--usually when you have to brake or swerve, turning a dicey situation into a catastrophic one.

The maneuver to recover from trailer sway (keep accelerating, apply trailer brake) is opposite most people's instinct (hit the brakes).
posted by lozierj at 11:02 AM on February 16, 2017 [2 favorites]

The received warning is not to worry about how much you can tow, but how much you can safely stop or handle in a side wind. You might have powerful engine, you might be within your tongue weight, but if you don't have a vehicle that has the ability to deal with a sudden stop or wind sheer on the trailer, you better buy more insurance.
posted by BlueHorse at 11:11 AM on February 16, 2017

>I've never towed anything before, but ...

No buts. Why do you want to second-guess the engineers that made your car, or the regulators that set the limits on tongue weight?

You can get a teardrop or raindrop trailer and remain within the tow and tongue weight limits of your car. They're cute beyond imagining. People are upgrading all the time, and you can buy them used. The sleeping arrangements are cozy for two, but not as tight as some that I have enjoyed.

If you want to tow something bigger, check to see if your car's manufacturer offers a towing package for your model and year; or upgrade your tow vehicle.
posted by the Real Dan at 11:40 AM on February 16, 2017 [3 favorites]

Aside from the good suggestions, above, you'll need to have a pig-tail installed at the rear of your vehicle to receive the trailer's electrical plug. Trailer brakes will actuate when you step on your car's brake pedal. Many small trailers don't have brakes, but you still must connect their lights to your vehicle with a pig-tail--a plug receptacle. If your vehicle is not already equipped, you must buy an aftermarket hitch assembly. Get a certified mechanic to install both the electrical pig-tail and aftermarket trailer hitch on your vehicle.

In Oregon, trailers with less than a one-ton max weight capacity do not need to get a license plate, but they must have working tail and turn signal lights. Your mechanic ought to be able to advise you, although a phone call to your DMV wouldn't hurt.

Be advised that successfully backing up small trailers are a bigger challenge than backing large ones. One reason is because the short distance between axels of the trailer and towing vehicle causes major oversteering--you sometimes get too far into your error to adjust, and you must pull forward and try again. Another reason is because many small trailers simply aren't visible in your mirror. You shouldn't try to master the technique on your first try--get a spotter and find an empty parking lot. Once you get the theory down, you can impress and amaze your friends with your prowess.

Mentioned above is trailer sway. This can be caused by light tongue weight, but low or uneven tire pressure in the trailer may contribute. Many small trailers have a "resonant" speed, at which the trailer begins to sway. If you feel it coming on, you may simply ease up on the accelerator, and then stay below that resonant speed.
posted by mule98J at 11:58 AM on February 16, 2017 [1 favorite]

There is a lot more to towing than just those two numbers, especially with not model info. To see if it's even feasible to consider you need to look at gross vehicle weight, loaded trailer weight, then your hitch capacity (sounds like yours is a Class I) then your vehicles towing capacity for its exact transmission, engine, brakes and cooling system configuration. And you have to take into account any modifications, weather, terrain, highway or local roads, speeds, type of trailer, trailer brakes, axles etc. Then you go with the LOWEST figure.
posted by fshgrl at 12:01 PM on February 16, 2017

Oh goody - I get to recommend Josh the RV Nerd! (I watch way too many of his walkthoughs!) Here he is talking about what you can tow safely:

There's probably also dozens of related youtube videos on the subject as well, but Josh's informational videos are top notch. Also related: Towing a fifth wheel with a half ton (and why/how things go wrong):
posted by cgg at 12:34 PM on February 16, 2017 [2 favorites]

Found this while continuing to search:

Typical kinja cool-bro prose, but it definitely seems that the Euros are okay with lower tongue weights because they're serious about slowing down while towing. Note the Delphi paper published by SAE that showed ok stability with a 3% tongue weight up to 65mph, but 10% was good to 100mph.
posted by hwyengr at 6:43 AM on April 19, 2017

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