Manufacturer's Tow Ratings

[DKB_SATX]

Originally Posted by Bruce B

I don't understand what you are referring to here. Are you saying your minivan engine makes more HP than your truck engine? Why refer to first gear?

Torque multiplies as a result of gearing. If you put 100 pounds feet torque into a transmission gear with a 10 to one reduction you now have 1000 pounds feet of torque. Now put that into your differential and multiply by that ratio. That engine torque becomes a big number....That is why different gear ratios make otherwise like vehicles feel so different. HP is HP, gear ratios have no impact on that, this has always been my understanding anyway...

Torque developed by an engine is just a small part of the equation. Torque curve and gearing play a very large part in the picture.

Just curious....
Bruce



Sent from my SM-N900V using Airstream Forums mobile app

Looking at his signature, he's got a 2000 Dodge 1500, so it's not difficult at all to imagine that a new minivan would have more horsepower and similar torque compared to the 318 (230 hp, 300 lb-ft) or 360 (245 hp, 335 lb-ft) available at the time.

A modern engine's torque curve can be MUCH flatter with better computer controls and especially with direct injection. Add forced-induction to that and the results are amazing, as we see in the Ecoboost engines from Ford. Huge amounts of torque available below 2,000 RPM, and a fat, flat torque curve way up into high RPM levels.

While the direct effect of reduction gears multiplies torque, the right choice of gearing also puts the engine in a "good" rpm range at the desired road speed. There are lots of trade-offs in what that "good" range might be (fuel consumption, power production, NVH, longevity, etc.)

PS: Yes I realize there aren't any Ecoboost minivans, I was just geeking about about modern engines.

[Road Ruler]

Originally Posted by rostam

Times have changed. We are not in the 70's anymore and almost no one uses a sedan as TV. Car companies know this and have softened up the sedans to reduce the cost and increase the profit;

Apparently a common misconception that modern sedans have been "softened up"....

Crash Test 1959 Chevrolet Bel Air VS. 2009 Chevrolet Malibu (Frontal Offset) IIHS 50th Anniversary - YouTube

[truckasaurus]

Originally Posted by dznf0g

IMO, no.

IMO No too. Looking at truck specs, if you add $$$$ options the tow rating goes down. Add diesel, 4x4, big wheels with low profile tires etc and the rating starts to dwindle. Often the big tow rating used for an advert is reg cab, 2x4, gas, 17" cheapie rims and no luxuries.

[MrUKToad]

Originally Posted by Road Ruler

Apparently a misconception that modern sedans have been "softened up"....

Wow!

[Chuck]

Originally Posted by Bruce B

I don't understand what you are referring to here. Are you saying your minivan engine makes more HP than your truck engine? Why refer to first gear?

That's the highest gear, in which you will get the most actual thrust at the drive wheels. engine torque x 1gear ratio x final drive (rear end) ratio /wheel diameter = thrust at the wheels.
My truck, in 1st gear, will produce 2000lbs. (weighs ~5300lbs, give or take)
the "mini" will produce 3000. (and weighs 4500).

truck engine--318v8, designed in the 1960s, 220hp, and a horrible torque curve--300ftlbs at its peak of >4000rpm; much much less at rpm's that you can actually use

Mini-3.6L: 283hp, 260ftlbs torque, and its a much wider torque band.

The mini is more truck-ish than my truck. Or...the truck is very pokey. (But nobody thinks I'm a nut-bar when I pull into the campground with it. )

Here's another fun fact: the new Durango with the Hemi motor (giant gobs of both hp and torque) only produces about 3200lbs of thrust in 1st gear, because of the lower gearing. But it weighs in at about the same as my truck, so...
With all of its HP, it probably won't shift as much on highway grades, but my point is just that thinks aren't always as they seem at first glance.

[jcl]

All of this discussion of cars compared to trucks for towing, and safety, yet no mention of the fact that passenger vehicles are designed, built, and tested to meet passenger vehicle safety standards that many trucks are exempt from due to their GVW. In other words, the starting point is safer.

I see debate about whether a hitch can be safely added to a passenger vehicle, but has anybody considered what it would take to re-engineer a pickup truck for passenger car levels of crash safety, performance in roll over tests, etc? It would be far easier to get the passenger car to tow than it would be to make the pickup truck equally safe in a crash, IMO.

Jeff

[dznf0g]

Originally Posted by jcl

All of this discussion of cars compared to trucks for towing, and safety, yet no mention of the fact that passenger vehicles are designed, built, and tested to meet passenger vehicle safety standards that many trucks are exempt from due to their GVW. In other words, the starting point is safer.

I see debate about whether a hitch can be safely added to a passenger vehicle, but has anybody considered what it would take to re-engineer a pickup truck for passenger car levels of crash safety, performance in roll over tests, etc? It would be far easier to get the passenger car to tow than it would be to make the pickup truck equally safe in a crash, IMO.

Jeff

NHTSA test and rates through 3500/350 (One ton) series. Not every year, every model as trucks don't change much during their lifecycle. Go to their website, you don't have to guess. Some trucks perform better than some cars in some categories. Cars generally do better than trucks in some categories. And some cars are better than other cars in some categories.

[Bruce B]

Originally Posted by jcl

All of this discussion of cars compared to trucks for towing, and safety, yet no mention of the fact that passenger vehicles are designed, built, and tested to meet passenger vehicle safety standards that many trucks are exempt from due to their GVW. In other words, the starting point is safer.

I see debate about whether a hitch can be safely added to a passenger vehicle, but has anybody considered what it would take to re-engineer a pickup truck for passenger car levels of crash safety, performance in roll over tests, etc? It would be far easier to get the passenger car to tow than it would be to make the pickup truck equally safe in a crash, IMO.

Jeff

I believe older pick up trucks were terrible in terms of being safe in an accident, newer trucks are being engineered with all the safety improvements available. Safety sells these days.

You do bring up something I have always wondered about though. What is the impact of the chassis stiffening done to enable a modern car tolerate the loads of towing a large trailer? Do these modifications impact the factory designed crumple zones or safety features?
Curious....
Bruce


Sent from my SM-N900V using Airstream Forums mobile app

[jcl]

I'd agree that older trucks were very poor for safety performance, and that newer ones are better.

I would expect intuitively that a rear crumple zone on a passenger car would be impacted slightly by a receiver. One vehicle that I installed a factory hitch involved stiffening to the rear unibody to support the receiver, and removal of the collapsible bumper supports. The bumper was stiffened, apart from the receiver, presumably so that it could still meet the bumper impact damage rules without the shocks. All of this was using factory OE parts, installed after delivery.

I wonder what comprises the rear crumple zone of a pickup truck? And how is it impacted by installing a heavy duty receiver?

This is all after the fact, though. I think the most important safety features are active ones, that allow one to avoid an accident in the first place.

Jeff

[dznf0g]

Most of the OE receivers are now actually THE rear cross member of the frame and designed that way. That's just in the last few years' new introductions. BUT, for GM, if it is offered as OE it is engineered and crash tested with the receiver installed.
However, with a PU there is 5 to 8 feet of "crumple zone" from bumper to occupants. It's really not defined as such, but offers a lot of distance from the intruder, so to speak.

[cameront120]

Originally Posted by dznf0g

However, with a PU there is 5 to 8 feet of "crumple zone" from bumper to occupants. It's really not defined as such, but offers a lot of distance from the intruder, so to speak.

Assuming that that 5 to 8 foot box is empty...

[dznf0g]

Originally Posted by cameront120

Assuming that that 5 to 8 foot box is empty...

true dat! Customers are responsible for their loads and their safety, just like what they tow.

Of course, the same concern is there for whatever you load in any vehicle rear compartment/space.

[mstephens]

Originally Posted by dznf0g

"many of them" and "facts" arent stats.

In order to settle this (and we won't because real data does not exist) one would need a collection of statistically significant samples carline by carline, with comparable groupings of towing mileages, of each carline. There would have to be equal groupings of those vehicles who exclusively tow within mfr limits and those who exceed mfr limits...by equally graduated amounts. I know of nowhere in the industry where this kind of data has been collected.

Anything less than that kind of empirical data is nothing more than cannon fodder. However, some of us live in that world (both inside knowledge of engineering and marketing practices and customer interface) and have experiences over decades which can offer educated opinions. But even that has no statistical absolute validity.

I didn't argue for a specific "statistic." I argued we have facts, and we do. CanAm could cite large numbers of sedans and minivans and SUVs they have set up, and that information is factual. They could talk about hundreds of these setups with hundreds of thousands of miles of towing. Not to form an MTBF statistic, or a model by model comparison, but to say that in their experience these setups DO TOW BIG AIRSTREAMS with no abnormal amount of failure.

The argument has never been about a statistical advantage of this over that. It has been people insisting that these sedans "can't tow" or "will fail" or "will create lawsuits" or "will kill people." The data we have may be small, but it is not insignificant.

The argument is all about documentation, not the actual performance. We don't tow on paper, we tow on the road.

[dznf0g]

I understand, mstephens, your position clearly. I have, in over 30 years, come May, seen and spoken to many customers who have sustained damage due to overloading. Some by towing and some by piling on the vehicle. sometimes it manifests itself by catastrophic component failure and sometimes by an unexpected shortened life of the overall vehicle system.
Although my observations, over the years, are not document-able by stats either (I only see the failed stuff...no one calls the Service Rep just to say "I've been overloading my vehicle for 100,000 miles and all is OK) they are real and relatively common.

The other, more human, characteristic thing I have noted is that a person who knowingly overloads their vehicle won't discuss their disbelief in specs after a failure because they realize who is really to blame. It's sort of a weird embarrassment thing....like when someone buys an item because they believe it's high quality, defends it to the hilt, then doesn't tell anybody when they have problems. They don't want to lose "credibility currency".

None of that is quantifiably identifiable here, but I am sure it exists.

BTW, I don't consider this an argument nor an indictment of anyone....merely a discussion of a topic of which I have extensive experience. I know I won't change any detractors from my position, but maybe for my part, I can inform some of those who haven't considered all the angles.

[Chuck]

Originally Posted by dznf0g

... Some by towing and some by piling on the vehicle. sometimes it manifests itself by catastrophic component failure and sometimes by an unexpected shortened life of the overall vehicle system.

What do you find tends to fail?

I've noticed another human characteristic, one that probably can't be quantified by statistics: some people are just hard on things. They break stuff.
Like the customer Bruce mentioned, who controls the speed of their vehicle with the brake pedal (instead of the correct way, which is with the throttle). The highest form of this is the guy (or gal) who drives an automatic with their left foot on the brake, and their right on the gas, and each has only 2 positions: fully engaged, or fully dis-engaged.
"piece of crap is on its 3rd tranny--nobody can figure out why"
gee, I think I have an idea...
I used to work at a place that had a fleet of 1-ton trucks carrying 700 tank-bodies (liquid)...overloaded if everything was really topped up, but not by a lot. Anyway, the mechanic there once told me that it was typical for him to replace trannies at 50 or 60k miles. I never had such a problem with my truck; but I didn't drive it like I didn't own it, like most people seemed to.

We have these same discussions on the plow forum. Its almost comical, the similarities. Just change the usernames, and replace the word "trailer" with "snow plow".
"you WILL burn the clutch out in 5 minutes, plowing with that Jeep". -um....no
"I used one of those once {light-weight snow plow made for non-commercial/personal use} it broke after 10 minutes "
-you're lying (most likely), or you're a complete idiot.

I had one of these plows for 8 years. It never "broke". The worst thing that happened to my truck during this time was that it got rustier.
Oh, and this particular truck isn't "supposed" to plow, either. (according to the manufacturer). BUT, when they say "plow," they mean "big, heavy, typically 800lb commercial plow...operated by someone who doesn't own it", not "200 lb home-owner special" Heck, Chrysler probably never even heard of such a thing.

[dznf0g]

Hi Chuck,
Yes the biggest factor in premature failure...all the way to the unsafe issues starts and ends with how loose or tight the nut located 3' behind the steering wheel is. Whether it is the choice and spec'ing of product, loading of the product, or operation of the product.

To answer your question of most common failures from overloading; of course it varies by type of vehicle and typical environment of usage but, in no particular order:

For overloading the vehicle with weight:
transmission
short brake life
frame fatigue/cracking
spring/hanger/pocket
axle bearings
rear end issues
once in great awhile...bent axle housings
Shorter than expected engine life
Generally a loose feeling vehicle all over

trailering:

transmission
brake life
rear end issues
shorter than expected engine life


Mind you, most all of my interface is with truck and van customers. However I also call on a lot of sales type accounts who use cars. Trailering is not typically allowed with these accounts, but they do overload trunks and rear compartments with samples, etc.

With these, I typically see alignment issues and tire wear due to not realigning independent suspensions with their typical heavy load. Maybe trannys sometimes, but not often. And short brake life. These instances are not nearly as common as commercial truck overloading.

Also, lest you think this is unique to my brands, it isn't. I frequently visit with my counterparts with most of the other brands and we share the same overloading stories. Also my accounts are pretty free with info about competitive brands.

[dznf0g]

I also used to see a lot of overheating, but relative new technologies, like overheat protection pretty much eliminated that. (Loose driver seat nut protection feature)

[mstephens]

Originally Posted by dznf0g

I understand, mstephens, your position clearly. I have, in over 30 years, come May, seen and spoken to many customers who have sustained damage due to overloading. Some by towing and some by piling on the vehicle. sometimes it manifests itself by catastrophic component failure and sometimes by an unexpected shortened life of the overall vehicle system.
Although my observations, over the years, are not document-able by stats either (I only see the failed stuff...no one calls the Service Rep just to say "I've been overloading my vehicle for 100,000 miles and all is OK) they are real and relatively common.

The other, more human, characteristic thing I have noted is that a person who knowingly overloads their vehicle won't discuss their disbelief in specs after a failure because they realize who is really to blame. It's sort of a weird embarrassment thing....like when someone buys an item because they believe it's high quality, defends it to the hilt, then doesn't tell anybody when they have problems. They don't want to lose "credibility currency".

None of that is quantifiably identifiable here, but I am sure it exists.

BTW, I don't consider this an argument nor an indictment of anyone....merely a discussion of a topic of which I have extensive experience. I know I won't change any detractors from my position, but maybe for my part, I can inform some of those who haven't considered all the angles.

My use of the word "argument" is in the debate sense. not anger sense. e.g. The case for a position.

[Chuck]

That darn steering wheel/seat interface nut is something they've never been able to design-out. Usually throws error code: ID: 10-T (ID10T)

[dznf0g]

Originally Posted by Chuck

That darn steering wheel/seat interface nut is something they've never been able to design-out. Usually throws error code: ID: 10-T (ID10T)

That's good...can I use that one?