How come (at least in America), most passenger cars are either not rated to tow anything at all, or occasionally at most, maybe 2000 lbs (generally for a large car)?

Is it a liability thing due to our lawsuit-happy culture? Is it because they want to upsell you to a truck or SUV?

The weirdest thing to me is that a 530i isn't rated to tow shit, but an X5 3.0 is rated to tow 5000 lbs or something.

8/22/2011 7:16:17 PM

suspension and brakes I suppose

8/22/2011 7:20:20 PM

I think some of it has to do with the strength of the unibody on modern cars being nothing like the old cars that were built on a chassis. Add to that the soft springs and minimal amount of travel and I'd expect that you wouldn't want much tongue weight at all on the rear of most factory cars. That's a little bit of a guess though.

I did read recently that the Volvo S60R is rated for 3300 lbs. That seems like it could be fun although I question how they came up with that number.

[Edited on August 22, 2011 at 7:49 PM. Reason : s]

8/22/2011 7:48:09 PM

^^ that doesn't explain why it's supposedly "ok" to tow with pussy crossovers.

and here's another example...a late-90s Ford Ranger with the 4.0 V6 is rated to tow something like 5500-6000 lbs. You mean to tell me it can do that, but a 535i or E55 AMG can't? What does a compact truck bring to the fight that a sedan like that doesn't? Power? Brakes? Chassis rigidity? Stout drivetrain? Stiff suspension? It sure as hell isn't gonna even compete with, much less trump, one of those big German sedans in those metrics. Wheelbase? That's important, and a long-bed extended cab Ranger has a few inches on the cars, but the regular cab models are even less.

Makes no sense to me.

[Edited on August 22, 2011 at 7:55 PM. Reason : maybe the body on frame vs unibody argument accounts for some, but then there's that X5 again.]

8/22/2011 7:53:32 PM

In the case of the X5 (and other SUVs such as the Jeep Cherokee) I would assume the unibody was designed with towing in mind. I'm sure it takes extra engineering, extra material, and extra weight that they're just not going to put on there for no reason. Heck, most people who own actual trucks and SUVs never use their towing features.

I'm still working off an assumption that the unibody is a weak link rather than any real facts though so I certainly could be wrong.

[Edited on August 22, 2011 at 8:02 PM. Reason : l]

8/22/2011 8:00:28 PM

Sensible, except that the same cars are rated to tow comparatively heavy loads in Europe. BMW, for example, sells OEM hitches (but they won't sell them in the North American market).

I think there are speed restrictions and stuff while towing over there (so you're not cruising down I-95 at 80+ mph towing two tons behind your 325i or whatever), but that would have very little to do with structural concerns.

8/22/2011 8:04:52 PM

a 540i is rated to tow 4400lbs of braked weight. the general rule of thumb is you dont tow anything more than 3/4 of vehicle weight without brakes. since most cars don't come with brake controllers, you get no rating. I have a friend who tows his bike to every event with a 1.8L miata. look up european manuals for your car and you'll find the actual numbers

8/22/2011 8:10:35 PM

It has a lot to do with suspension travel as well as well as the would-be height of the tow point. A vehicle with more suspension travel should be able to maintain control longer at towing extremes, for example under heavy braking. Its hard to design and build a proper hitch assembly for an e55 that puts the tow point close to the proper height for the average 5000lb trailer (which I want to say is 17 inches??) without it being ridiculous.

8/22/2011 8:18:48 PM

Most trucks don't come with brake controllers, either.

I'm not worried about practical/safe limits...if I bought a sedan to tow with, I have no doubt that with a braked trailer, it would be perfectly fine towing anything I'd put behind it (waverunner, small enclosed trailer with a small sports car or a motorcycle or two, modest size boat, etc). I've seen the european limits...they're all plenty high.

It's more of an academic question...I'm just curious. That, and I'm slightly concerned about potential liability concerns if I did buy a car to tow with and was involved in a wreck.

[Edited on August 22, 2011 at 8:21 PM. Reason : ]

8/22/2011 8:19:23 PM

[Edited on August 22, 2011 at 8:59 PM. Reason : oops]

8/22/2011 8:52:15 PM

Yeah it has nothing to do with brake controllers.

It does have to do with the suspension though because there is more to the dynamics of towing than just being able to move additional weight. For example full size sedans and wagons up through the 80s were towed with regularly, because a heavy vehicle with its heavy vehicle suspension and heavy vehicle brakes could handle it. Braked trailers aren't the magic bullet here, your tow vehicle still needs to be able to stop itself and the laden trailer behind it in an emergency should the trailer brakes fail (and they will fail).

Your concerns about the liability are founded, because if you got into a situation where you were towing that new trailer behind a little car and got into almost any kind of accident you simply won't convince the highway patrol that what you were doing in the roadway like that was OK.

8/22/2011 8:59:45 PM

Quote :

"For example full size sedans and wagons up through the 80s were towed with regularly, because a heavy vehicle with its heavy vehicle suspension and heavy vehicle brakes could handle it."

I'll bet money that a '77 LTD or an '87 Caprice doesn't weigh as much as a modern 5-series or E-class, and it sure as shit isn't even playing the same sport when it comes to brakes or suspension.

[Edited on August 22, 2011 at 9:21 PM. Reason : i'm not worried about an overloaded vehicle ticket so much as about some ambulance chasing lawyer.]

8/22/2011 9:20:33 PM

http://www.youtube.com/watch?v=e8a71x6H8_4

8/22/2011 10:05:51 PM

Its not the "overloaded vehicle" ticket or the ambulance chaser you should be worried about, its the fact that when you are towing a car trailer behind a 5 series, or a bass boat behind a mazda 3 and someone pulls out in front of you and the trailer brakes decide to not work that you will definitely be found at fault and your premiums skyrocket.

While the brakes on a late model 5 series or e class probably are high performance enough to dissipate a large amount of heat, they simply aren't designed to be used for stopping increased loads, where as the brakes on a 78 caprice are virtually identical to the brakes found on a 78 3/4 ton chevy pickup.

I think you are thinking about my comment regarding the suspension the wrong way. In a e55 (sans trailer :busted: ) when you slam on the brakes it determines the line pressure to the calipers based on a preset value for the vehicles weight and the speed it is currently traveling (among other shit I am sure) and does what it can to keep from locking the wheels up.

8/22/2011 10:06:55 PM

Quote :

"While the brakes on a late model 5 series or e class probably are high performance enough to dissipate a large amount of heat, they simply aren't designed to be used for stopping increased loads, where as the brakes on a 78 caprice are virtually identical to the brakes found on a 78 3/4 ton chevy pickup. "

I don't see what the distinction is. I am pretty confident that the German sedans' brakes will generate a lot more torque and dissipate/cope with a lot more heat. From a stopping perspective, that pretty much covers it, at least when it comes to brakes. There's nothing magical about the brakes on the Caprice that will allow them to underperform the brakes on a 535i or especially an E55 AMG, yet mysteriously become superior when an extra couple thousand lbs is at play.

As far as the doomsday scenario where someone pulls out in front of you and then your trailer brakes shit the bed, well, I'll bet money that if you're fucked in the 535i, you'd be at least equally fucked in the '98 Ford Ranger.

[Edited on August 22, 2011 at 10:19 PM. Reason : Think an X5 3.0 has more brake than a 535i? What about an ML320 vs a E55 AMG, haha?]

[Edited on August 22, 2011 at 10:19 PM. Reason : and again, these cars are rated to tow outside of America]

8/22/2011 10:15:12 PM

How come a Volvo V70 is least rated to tow 3300 lbs? Hmm, Volvo doesn't make light trucks.

I think the larger Subaru wagon is the same way. Again, they can't upsell you to a truck, because they don't make one.

8/22/2011 10:23:29 PM

the holden monaro is rated to tow 1600kg (3500 lb) in AU
the exact same car with a pontiac sticker is rated to to 0

8/22/2011 10:35:43 PM

i dont understand the argument about upselling to a truck? and are you trying to validate the purchase of a car to do your towing duties or what?


hell it could revert to manufacturer warranty claims related to drivetrain/suspension component failure

8/23/2011 7:39:50 AM

^^and the ute does have less weight over the rear end, and sub-frame connectors to uprate its capacity.

autotrader.com

compare cars lists all towing capacities

1500lbs for my 4 banger.


1000lbs for a gto mustang etc.


i really think its rear spring strength and overall chassis strength
on some shitty cars like a yaris brakes may come into play



[Edited on August 23, 2011 at 8:13 AM. Reason : .]

8/23/2011 8:07:10 AM

Quote :

" I don't see what the distinction is. I am pretty confident that the German sedans' brakes will generate a lot more torque and dissipate/cope with a lot more heat. From a stopping perspective, that pretty much covers it, at least when it comes to brakes. There's nothing magical about the brakes on the Caprice that will allow them to underperform the brakes on a 535i or especially an E55 AMG, yet mysteriously become superior when an extra couple thousand lbs is at play."

I'm with Duke on this one. High performance braking systems are designed to have a very high heat capacity. I'm pretty sure the E55 has 14" rotors and 8 piston calipers on the front, slightly less so in the back. That is superior to anything found on any full sized Chevy or Ford pickup on the market today. And if he was really worried about the increased load on the braking system you could probably use track pads that are designed for higher heat loads.

Something else to think about is that the E55 AMG has a self leveling rear air suspension (though I'm not sure which model E55 that was introduced on...it actually might not have come around till the E63 to be honest...)

8/23/2011 9:32:39 AM

Quote :

"i dont understand the argument about upselling to a truck?"

SUVs are cash cows for auto manufacturers. If they maintained that you pretty much must have one to tow anything, that would help to "upsell" a few more would-be car buyers. I don't know, just a thought...I can't really think of any clear reason that they would de-rate cars for towing in the American market, AND simultaneously have the tall crossovers based on those very same cars rated to tow plenty.

Quote :

"and are you trying to validate the purchase of a car to do your towing duties or what?"

Well, that's how the question came up, and that's still part of it. Part of it's just curiosity, though...it just doesn't make any sense to me.

I want to be able to do some modest towing (waverunner, 18-20' boat maybe, Super Seven or turbo Miata in a small single-axle enclosed trailer, etc), but nothing close to the point where I'd need my Ram (once I get to FL in a few days), so I want to sell it. I started Googling the tow ratings of some different things that I thought might make good DDs and still handle the modest towing I need.

8/23/2011 9:49:56 AM

The distinction comes at a certain weight cut-off


sure these cars have awesome equipment... but put 5, 7, 12k behind one of these things and do the same for a 1-ton truck... you get the picture.

8/23/2011 9:50:12 AM

holy shit, yeah there's no comparison. I'm not talking about towing that kind of weight, and I'm not comparing them with a 1-ton truck.

[Edited on August 23, 2011 at 9:53 AM. Reason : I towed 10k literally from coast to coast with my Ram...not gonna happen with any car, haha]

8/23/2011 9:52:15 AM

i understand... the argument is silly to me, so i'll bow out.



(obligatory dodge magnum *cough*)

8/23/2011 9:57:48 AM

^ dodge magnum is titled as a truck in most states. (caugh)

yeah i don't think any heavy german sedans should have a problem

i know longer wheel base vehicles tow better, i know heavier vehicles tow better, and i know powerful vehicles tow better all of these add up to a truck being ideal.

Brakes would be an issue if your brakes were barely capable of stopping the car under normal conditions.

Spring strength and chassis strength i think are the biggest two.

Also gearing comes into play and on autos, so does having a trans cooler or something to make sure you don't over heat the fluid and the clutches.

Also keep in mind a Mercedes v12 biturbo may have 700+ft-lbs of torque but the drivetrain isn't built to handle that kind of twist for sustained periods. Their thought is if this car makes 700ft-lbs for 10 seconds its going 180... not this thing is going to need 700 ft-lbs for the next 20 minutes while we haul this trailer up the mountain.

Trucks have stronger axles lower gearing and beefed up transmissions... cars don't.
Even crossovers get an extra 20% lower gear set then their auto equivalents, and that is AFTER larger wheel/tire package is calculated in.

[Edited on August 23, 2011 at 9:59 AM. Reason : .]

8/23/2011 9:58:22 AM

How's a Dodge Magnum classified as a truck? It's 100% a car. There's isn't even the hint of a grey area here.

^all valid points, but moreso for towing heavier weight than what Duke is proposing.

[Edited on August 23, 2011 at 11:28 AM. Reason : k]

8/23/2011 11:27:11 AM

you'll notice the hatch opens up forward of the rear of the vehicle?


apparently that was enough for them to only have to meet truck emissions standards at the time of launch or... thats what the dealer at lake norman told me which i now feel silly for taking seriously because dealers are usually soo full of bullshit they can't see straight.

8/23/2011 11:33:43 AM

^^ Yep, or with a lesser car. I mean, a 2-ton full-size sedan with 400-500 hp, autobahn-ready brakes, a fairly stiff chassis...we're not talking about your sister's Camry, here.

but again, the question isn't so much whether a car like that will tow a 2500-3000-lb braked trailer safely. It's why it isn't rated to do it in America.

[Edited on August 23, 2011 at 11:55 AM. Reason : ]

[Edited on August 23, 2011 at 11:56 AM. Reason : for that matter, why in the hell would a Magnum be any better than a 5-series or E-class?]

8/23/2011 11:53:29 AM

I say go for it and report back

[Edited on August 23, 2011 at 12:00 PM. Reason : You should go for this setup!]

8/23/2011 11:58:41 AM

That's exactly the idea, except that I want an enclosed trailer (with a rooftop AC unit ) and a smaller Lotus. (and I can't afford, or rather am unwilling to spend the money, for a Panamera and an Elise. Plus the Panamera looks weird in the rear).

A 7x14' single axle weighs about 1000 lbs...a Seven is ~1200-1500 lbs (for a total weight of 2500 lbs). My Waverunner + trailer is probably 850-900 lbs. A folding motorcycle trailer, even with 2 bikes on it, would be barely over 1000 lbs. A big German sedan would tow any of those things easily, as long as I could back the ski into the water without dunking the ass end of my car (might depend on the steepness of the ramp).

About the only thing I might conceivably want to tow that I'd be concerned about would be an 18-20' boat. I wouldn't be too worried about towing it, but I don't think I'd want to try to pull it up a boat ramp with a car.



(but part of me wants to buy a 996 Turbo and DD it as well as just drive it to the track, as well as tow the Waverunner and single motorcycle trailer with it...they're badass, and it won't be too much longer before my daugher gets too big to ride in the back, and once that happens, a 911 will no longer be viable primary transportation for me for a long time).

[Edited on August 23, 2011 at 12:13 PM. Reason : ]

8/23/2011 12:09:31 PM

going through the mountains or anything like that would kill the trans mission in a automagic car.


I know a 5.8 liter ford truck w/o factor tow package overheated the tranny with a 20' boat on the way to smith mountain lake...

if you're not doing anything like that it should be ok.

8/23/2011 12:13:44 PM

Quote :

" apparently that was enough for them to only have to meet truck emissions standards at the time of launch or... thats what the dealer at lake norman told me which i now feel silly for taking seriously because dealers are usually soo full of bullshit they can't see straight."

Yeah there's no way that's remotely true. Just another dealership feeding out a line of bullshit.

8/23/2011 1:08:10 PM

Quote :

" as long as I could back the ski into the water without dunking the ass end of my car"

tounge extension. easy fix and will make the trailer tow better and be easier to back down the ramp. Hell, get one that will fit all of your trailers and bolts in and you can mount a plastic toolbox to it to keep your supplies that you dont want in the back of your luxury german wagon.

8/23/2011 1:10:18 PM

Quote :

"Also keep in mind a Mercedes v12 biturbo may have 700+ft-lbs of torque but the drivetrain isn't built to handle that kind of twist for sustained periods. Their thought is if this car makes 700ft-lbs for 10 seconds its going 180."

^^^ and speaking of which, those hot German sedans are designed to comfortably and reliably operate at a sustained 150+ mph. That takes a not-insignificant amount of sustained power output.

[Edited on August 23, 2011 at 1:14 PM. Reason : ^ thought about fabbing up something like that...didn't know they were readily available]

8/23/2011 1:12:59 PM

Once your daughter is too big to fit in the back of the 996, what will happen?

Also, you've been talking about a 911 for about what 35 years now? Are you going to get one? Also, yes please do.

8/23/2011 1:58:44 PM

My dad fabbed one for me from some scrap he had. I think he just welded together two sticks of 2x4 steel tubing and those just slide into the existing tongue. Put 3 big ass bolts through the whole thing and it was good to go. I needed to add about 3 feet to a jet ski trailer to accommodate a small boat i have.

quick search shows that they are commercially available for less than $100. Not sure how much your materials would run, it may be cheaper to just buy one if you dont have the appropriate scrap.

8/23/2011 2:06:30 PM

Also, I'd have no reserves about thinking an uber wunder sedan would be able to handle towing significant loads. Sustained 150mph + places thermal loads on components that would be very significant. Heat output from axles, wheel bearings, engine/exhaust, transmission/diff, etc. would all be tremendous.

That said, you realize 911s have seats in the front also!11 You know, for bigger daughters to fit into!1


PS: I've towed 1500lbs w/a Volvo 850 turbo wagon (rated to 3300lbs right here in the U.S.), it did so like a champ. It also enjoyed having 5 grown ups in it being driven by a grown man w/the sensibilities of an infant -me- on a ski trip (mountain roads), and handled that just fine. 5 grown Americans add up to roughly 1 billion lbs I believe.

8/23/2011 2:27:29 PM

Yes, the heat load would be immense but the cooling ability of 150 mph air is also immense

8/23/2011 2:42:45 PM

^^ Well, I mean, the point is that since I'm about to have 50% custody, I'm gonna want something that seats more than 2 people as my daily driver. Doesn't have to be done immediately, but eventually I'm gonna get tired of taking the car seat in and out, or not being able to carry any adult passenger in my car, etc.

Quote :

"5 grown Americans add up to roughly 1 billion lbs I believe."

At least.

8/23/2011 2:49:04 PM

^you're short, the child's mother is short, I'm sure your daughter will stay short. Sitting in the back of the 996 shouldn't be an issue

8/23/2011 3:34:32 PM

Quote :

"It also enjoyed having 5 grown ups in it being driven by a grown man w/the sensibilities of an infant -me- on a ski trip (mountain roads), and handled that just fine. 5 grown Americans add up to roughly 1 billion lbs I believe."

i can corroborate this story.

8/23/2011 4:33:12 PM

theDuke866, if you're looking for a diesel, highish mpg dd that's cheap, look into a used sprinter. i've seen higher mileage ones under 10k. they get 28ish mpg unloaded. they can pull 5k lbs and the storage in the back is retarded. you could fit your PWC or bike or both inside and reserve the trailer for moving/hauling a car to the track. super cheap tires for the 15" wheels, too

8/23/2011 5:05:31 PM

I would tow with a car. Most of the cars in US are not rated because rear bumper rebar is not designed with at hitch or there is no available hitch for the car. If mfg does put one as an option (or rebar has the option to attach the hitch), they would most likely have to retest the crash safety testing, which is a royal PITA for them. Power wise and cooling wise they are able to tow without much problems. Suspension, axle size and weight wise you would be more limited than a truck, but that's not to say you couldn't tow 2-4k load with a big sedan.

If any of you goons think a car can't tow much, take a trip to the old continent. Ton of cars towing.
Also, here is the official word on from VW on towing from none other, but GOLF!

http://www.volkswagen.co.uk/volkswagen-world/news/185

http://www.volkswagen.co.uk/volkswagen-world/news/162/double-victory-for-volkswagen-golf-at-towcar-awards-2009

If Golf with its 4 cyl diesel can tow, I assure you longer wheel base 540i or 530i can tow MUCH MORE!

for the record, this guy retrofitted a tow hitch on his 335i coupe

http://www.e90post.com/forums/showthread.php?t=58387&highlight=jetski



[Edited on August 23, 2011 at 6:55 PM. Reason : d]

[Edited on August 23, 2011 at 7:05 PM. Reason : F]

8/23/2011 6:52:37 PM

we have all been trolled

8/23/2011 7:21:21 PM

i love this pic

8/23/2011 7:33:47 PM

God someone is fucking stupid and its not me this time

Have you ever seen a cv joint or a frontwheel drive transmission.

8/23/2011 9:06:00 PM

Quote :

"for the record, this guy retrofitted a tow hitch on his 335i coupe"

I tow my stand up jet ski, sit down ski, and ATV with my Honda Civic all the time. Anything under 800 lbs isn't really a concern for me. This thread is relevant to me more for the idea that I would consider selling my 4Runner and buy a 545i or something to tow the boat with. 3,000 lbs, 4,000 lbs, or 5,000 lbs is a whole different world than the sub 1,000 range IMO.

8/23/2011 11:48:44 PM

Absolutely...but 3000-4000 lbs is in turn a lot different from 7000-8000 lbs where you without a doubt need a full-size truck or SUV.

8/24/2011 12:12:20 AM

^ I'm with you on the 7k-8k thing. I'm just not going to be impressed by a 335i doing something that I've already done with a Civic and a Saab 900.

If I felt I could safely pull my boat that is over 3k# on the trailer I'd be very interested. I've been wanting to get into a single car for a while and I've thought many times that I'd be better off with a BMW X5 than I am with a Civic and a 4Runner. I've towed it short distances with vehicles as small as my old Wrangler, but I don't think I'd ever consider getting on the highway and towing it back and for to Raleigh unless I was 100% convinced it was safe and it wasn't going to eat up my transmission/clutch in the process. This thread is definitely relevant to my interests.

[Edited on August 24, 2011 at 12:22 AM. Reason : l]

8/24/2011 12:18:37 AM

i think towing the weight of your vehicle is on the ragged edge of what it may be designed to tow.

8/24/2011 8:19:18 AM