Tow Questions

[ronerjones]

Sorry I know this has been discussed extensively but I am getting ready to buy a new tow vehicle and I do not want to buy something too small and I do not want to over purchase as my pockets have many holes these days.

Coleman 2002 Utah - GVWR 3,450 - Gross axel weight 3,050 - Tounge Rating 400 - Unloaded vehical weight 2,485 - unloaded axle weight 2,370 - unloaded tongue weight 115

I currently own a 2003 Toyota Tundra I think it is a little under powered for the trailer completely loaded

The smaller Tundra V6 has a max tow rating of 4,800 - GVWR 6,400 - Payload of 1,470

I am guessing that my trailer fully loaded A/C unit and with 4 bikes mounted to the roof is about 4,000 lbs and I am being generous. In the bed of the truck I would typically have 300-400 lbs of gear and 4 warm bodies 450 lbs.

Does the smaller Toyota mean that I can tow a trailer up to 4,800lbs and have another 1,400 lbs of cargo. I am trying to decide if I need to get the V8 in order to be set up properly.

[ronerjones]

I would also like to ask that you suggest my minimum tow requirements that I should be looking for thanks for all suggestions.

[wavery]

Tow rating means very little. Almost all manufacturers rate the maximum tow capacity with the vehicle empty (although few people tow without at least a driver). There are many ratings that must be considered when towing, the tow rating is the LAST thing to be considered. The fact is, that's the only thing that most people consider and they just don't understand what they are doing.

The most important rating to consider for towing is the GCWR (Gross Combined Weight Rating). This is the maximum weight that a vehicle can safely tow (actually stop) including the combination of TV, trailer, passengers, cargo and fuel.

You have a few of the numbers that are critical. Your laden trailer weight of 4000#, your passenger & cargo are about 850# plus about 100# of fuel, make it and even 1000#. That makes your total added (combined) burden around 5000#.

You need a vehicle with a GCWR minus TV curb weight that has room for an additional 5000# without exceeding the max tow rating (which should exceed 4000#).

My guess is, the Tundra V6 may do quite nicely......the key is the GCWR.

[coach]

Why would you load a trailer rated to 3450 lb to 4000 lbs, it's limit is 3450???

You tow vehicle with the 4800 lb rating is enough to tow the trailer and family. With people and cargo, it will near it's max ratings. WDH should be considered. Overloading the trailer is what I would advise against!

Adding the tow package to the V6 - tacoma
http://www.toyota.com/tacoma/specs.html

The GCVWR = 11,100 wow!
11100 less curb of 3835 = 7265, more than enough for the 6500 lb max tow rating!

[wavery]

Why would you load a trailer rated to 3450 lb to 4000 lbs, it's limit is 3450???

You tow vehicle with the 4800 lb rating is enough to tow the trailer and family. With people and cargo, it will near it's max ratings. WDH should be considered. Overloading the trailer is what I would advise against!

Adding the tow package to the V6 - tacoma
http://www.toyota.com/tacoma/specs.html

The GCVWR = 11,100 wow!
11100 less curb of 3835 = 7265, more than enough for the 6500 lb max tow rating!

Good catch.......I missed that. I just noticed this, "Gross axle weight 3,050". It always puzzles me why the gross trailer weight rating is usually higher than the axle rating. I guess they are figuring that at least 10-15% of the weight will be on the tongue....

Overloading the trailer is begging for a blow-out of the tires. Good idea to check the weight rating on the tires too.

[AustinBoston]

I just noticed this, "Gross axle weight 3,050". It always puzzles me why the gross trailer weight rating is usually higher than the axle rating. I guess they are figuring that at least 10-15% of the weight will be on the tongue....

In addition, they know a significant number of owners will use a WDH, which pushes tongue weight back onto the axle.

The best we can do is to emphasize that every rating is the absolute maximum under ideal circumstances.

Most SUV tow ratings should be divided by 1.3 for towing in the mountains, where you need more horsepower and especially more brakes.

ronerjones: Your Utah probably has electric brakes.  No SUV will be rated to tow it unless the trailer brakes are properly functioning.

Austin

[austinado16]

...Most SUV tow ratings should be divided by 1.3 for towing in the mountains, where you need more horsepower and especially more brakes...Austin

[class]
This is a neat little saying, "Torque wins races, horsepower sells cars."

Just ask folks at Audi who continue to win at the 24hr Le Mans year after year with their diesel powered race cars.

Torque is what makes power
[/class]

[AustinBoston]

[class]
This is a neat little saying, "Torque wins races, horsepower sells cars."

Just ask folks at Audi who continue to win at the 24hr Le Mans year after year with their diesel powered race cars.

Torque is what makes power
[/class]

If you are trying to win a race while towing, you are making a big mistake, and I don't think it's wise to draw towing wisdom from racing wisdom.

I realize there is a lot of smoke-and-mirrors in the horsepower rating game, and it is true the torque moves trailers.  But the only thing needed to change horsepower into torque is gears.  That's the idea with higher ratio differentials; same horsepower, same engine, same transmission, more torque, less fuel mileage.

But the real point of my horsepower statement has to do with the fact that normally aspirated internal combustion engines loose between 2% and 4% of their power for each 1,000 feet of elevation.  So at the top of an 8,000 foot pass, an engine without a turbocharger is down between 16% and 32% of it's sea-level horespower.  That loss is across the RPM spectrum, so it ends up translating to torque as well.

The part about brakes should be obvious.  :yikes:

Austin

[austinado16]

If you are trying to win a race while towing, you are making a big mistake, and I don't think it's wise to draw towing wisdom from racing wisdom.

I realize there is a lot of smoke-and-mirrors in the horsepower rating game, and it is true the torque moves trailers.  But the only thing needed to change horsepower into torque is gears.  That's the idea with higher ratio differentials; same horsepower, same engine, same transmission, more torque, less fuel mileage.

But the real point of my horsepower statement has to do with the fact that normally aspirated internal combustion engines loose between 2% and 4% of their power for each 1,000 feet of elevation.  So at the top of an 8,000 foot pass, an engine without a turbocharger is down between 16% and 32% of it's sea-level horespower.  That loss is across the RPM spectrum, so it ends up translating to torque as well.

The part about brakes should be obvious.  :yikes:

Austin

Racing while towing? What are you talking about?  My comment was merely that it's torque that is power, not horsepower.  Can you change gear ratios for maximum torque from any engine?  Sure......but that doesn't mean you'd want to tow with it.

[wavery]

It depends on whether you are talking about torque at the flywheel or torque on the ground. If you're talking about torque to the ground, gearing will matter but it will also mess with the optimum RPM/torque range of the engine.

Higher torque engines have a larger bore and shorter stroke with a little tweaking of the lift & duration on the camshaft.

The ideal towing engine is high torque at about 2500-2800RPM (a little lower for diesel). That's why I chose the 4.3L Chevy V6 that I did. It's only 190HP but it has 250# of torque at 2800RPM. Mix that with a 3.42 gear ratio and it will pull just as strong as a lot of V8s (plus it's light) without the sacrifice of gas mileage when not towing.

When you are pulling a hill, it's the torque at mid-range RPM that will keep you from having to downshift to achieve more power to the rubber.

[AustinBoston]

Racing while towing? What are you talking about?

Hint:

[class]
This is a neat little saying, "Torque wins races, horsepower sells cars."

Just ask folks at Audi who continue to win at the 24hr Le Mans year after year with their diesel powered race cars.

Torque is what makes power
[/class]

You are the one who mixed the two, not me.

My comment was merely that it's torque that is power, not horsepower.  Can you change gear ratios for maximum torque from any engine?  Sure......but that doesn't mean you'd want to tow with it.

Can you find the blatant contradiction in that statement?

The fact is, to get the torque needed to tow, you must have - absolutely must have - horsepower.  How that horsepower is created and utilized is another matter entirely.  

More to my point: If you've lost 32% of your horsepower at altitude, you have lost 32% of your potential torque as well.  End of story.

Austin

[flyfisherman]

It depends on whether you are talking about torque at the flywheel or torque on the ground. If you're talking about torque to the ground, gearing will matter but it will also mess with the optimum RPM/torque range of the engine.

Higher torque engines have a larger bore and shorter stroke with a little tweaking of the lift & duration on the camshaft.

The ideal towing engine is high torque at about 2500-2800RPM (a little lower for diesel). That's why I chose the 4.3L Chevy V6 that I did. It's only 190HP but it has 250# of torque at 2800RPM. Mix that with a 3.42 gear ratio and it will pull just as strong as a lot of V8s (plus it's light) without the sacrifice of gas mileage when not towing.

When you are pulling a hill, it's the torque at mid-range RPM that will keep you from having to downshift to achieve more power to the rubber.

I'm very fond of GM's 4.3 V-6, I think it's one of the very best engines GM ever produced. And I pondered rather continueing on with the 4.3 when I bought my present GMC Sierra. At the time (2002) I had plans for motoring west with the PU; and Mr.GoodWrench's admonishment for high-altitude performance is that for every 1,000 feet above sea level the engine loses about 4% of it's performance. So driving by Denver's Mile High stadium would mean a loss of 20% of the engine's performance. Already know of some mountain passes that exceed 10,000 feet so I decided to go with the 4.8 V-8.

Now having driven trucks with both engines (4.3 V-6 and the 4.8 V-8), with the same rear end gear ratios (3.42)  and  pulled the same popup camper with about the same loads over the same roads, really have had a chance to compare
both engines. First off, with out towing anything, the V-6 would give better gas mileage by at least 2 mpg ... 3 mpg in town driving. But here's the interesting part, towing the V-8 delivers 2 mpg better than the V-6 ... just the opposite! Now since most of my driving is not towing (like maybe 95%!) and never made that trip west because of sky rocketing gas prices, I wish I would have stayed with the V-6.

Another interesting comparision of these two engines is the high torque, low rpm of the V-6 (260 lb-ft @2800 rpm) and the V-8 (285 lb-ft @4000 rpm). The net H.P. for the V-6 = 200 @4600, and the V-8 = 270 @5200. On a couple different campsites I frequent here in western NC, where you have to climb a steep mountain, winding grade, to get to them, the V-6 would just hunker down and deliver the needed power without a big fuss, whereas you can hear the additional roar of the V-8 to get the needed rpm's for that power. One other point, and this is Fly's definition of torque vs h.p. (and don't any of you wizz kids try and confuse me with facts!) ... torque gets the thing in motion, up to speed as it were, and horse power maintains the speed. Explains why the V-8 gets better gas mileage towing ... it's kinda lopping along the byway whereas the V-6 is having to work harder at it under load.


Fly

[austinado16]

Another interesting comparision of these two engines is the high torque, low rpm of the V-6 (260 lb-ft @2800 rpm) and the V-8 (285 lb-ft @4000 rpm). The net H.P. for the V-6 = 200 @4600, and the V-8 = 270 @5200. On a couple different campsites I frequent here in western NC, where you have to climb a steep mountain, winding grade, to get to them, the V-6 would just hunker down and deliver the needed power without a big fuss, whereas you can hear the additional roar of the V-8 to get the needed rpm's for that power. One other point, and this is Fly's definition of torque vs h.p. (and don't any of you wizz kids try and confuse me with facts!) ... torque gets the thing in motion, up to speed as it were, and horse power maintains the speed. Explains why the V-8 gets better gas mileage towing ... it's kinda lopping along the byway whereas the V-6 is having to work harder at it under load.


Fly

And there's the cold hard facts about torque vs. HP right there.  Torque is what makes power, HP is just bragging rights......and low end torque (torque maximums produced at lower rpm ranges, is the kind of torque that produces the power you want for normal use, because it's there where and when you need it.

My '90 Suburban with throttle body injection, 9.3:1 compression, 5.7L (350ci)V-8 is 210hp @ 4,200rpm and 300lb-ft of torque @ 2,400rpm.  It gets about 14-15mpg towing and 17-18 not towing, if I keep the speed down.

[AustinBoston]

Torque is what makes power

I know you don't answer direct questions, but I'm going to ask one anyway.  You keep saying this and saying this.  Do you have some kind of scientifc document that makes this claim?

Austin

[wavery]

I know you don't answer direct questions, but I'm going to ask one anyway.  You keep saying this and saying this.  Do you have some kind of scientifc document that makes this claim?

Austin

Holy cow Austin.............give it a rest....... :eyecrazy:

Torque and HP are simply 2 different ways of measuring an engines performance qualities. Either can be tweaked by various methods of tweaking fuel/air ratio, stroke, bore etc. Often when one is enhanced it is at the expense of the other.

When it comes to towing, people should be able share their experiences without causing arguments or providing, "Scientific proof' of the way that they word their post.......... :rolleyes: ........good grief.......