Should Your Pickup Tow Less at Altitude?
By Tim Esterdahl
We do a lot of strange things as auto writers (including driving some pretty nice pickup trucks), but one thing I occasionally like to do is look through and read owner's manuals, especially the parts on towing and hauling.
While recently testing a 2015 Ford F-150, I looked through its manual and found this on page 251: "Note: For high altitude operation, reduce the gross combined weight by 2% per 1000 ft. (305 m) starting at the 1000 ft. (305 m) elevation point."
Interestingly, we could not remember reading or hearing about anything like this from any of the other manufacturers before. Clearly, this means that the truck's carrying capacity (found in the gross vehicle weight rating) and maximum towing capacity (found in the gross combined weight rating) would be negatively impacted at higher elevations in significant ways. In fact, this made us wonder why only Ford would offer such advice. Was it responding to some kind of pending litigation or was this just good customer safety awareness?
Defining Terms
In the name of clarity, we need to review a couple of terms:
- Gross vehicle weight rating is the maximum weight in pounds your pickup can carry — which includes passengers, cargo, a full fuel tank and lubes, the vehicle itself and any related tongue weight when towing.
- Gross combined weight rating is the maximum weight in pounds your pickup can carry and tow — which includes your pickup at max GVWR (including tongue weight) plus the actual weight of what's being pulled behind the pickup.
Interestingly, as we discovered, this note in the manual about GVWR and GCWR numbers is not new. We looked at 2013 Ford F-150 and 2014 Ford F-150 owner's manuals and found the same note. We found it in the 2015 Ford F-250-550 owner's manual as well.
Anyone who drives at higher elevations knows that the higher you go, the less powerful your engine feels, especially naturally aspirated gasoline engines. This is something the recreational vehicle industry always has been pretty good about communicating to its customers, as they tend to explore remote campsites in the mountains. We found a good explanation in Ford's 2013 RV and Trailer Towing Guide: "Gasoline engines lose power by 3-4% per 1,000 ft. elevation. To maintain performance, reduce GVWs and GCWs by 2% percent per 1,000 ft. elevation."
What About Turbocharged Engines?
To be fair, most people understand the common sense idea that at higher altitudes, the air is less dense so a vehicle (or person for that matter) is likely to have more trouble breathing as freely as it did at sea level. But what about Ford's twin-turbo EcoBoost? Can't that engine just spin the turbos faster and pull in more air?
Ford Truck Communications Manager Mike Levine said that while yes, "turbocharged EcoBoost engines have the capability to deliver a similar boost level at higher altitudes when the atmospheric pressure is decreasing," this same drop in atmospheric pressure is typically the reason why both power and torque decrease in naturally aspirated engines. While maintaining the same boost level at lower altitudes, Levine noted, other limits can be encountered, like turbo speeds at higher rpms that could also result in a power reduction (at higher elevations), but still have a smaller amount or no reduction of peak torque.
Because EcoBoost engines can lose some performance, Levine said, a reduction in the GCWR is recommended if customers want to maintain the same performance level they had when driving the same truck and trailer at sea level. We would also note that, although not as significantly impacted, the bigger, torque-biased diesel engines encounter the same type of performance challenges.
Why Does This Matter?
The obvious reason is safety. Every pickup sold in the U.S. is required to post maximum ratings and capacities, normally found on the driver's side doorjamb, so drivers know what they can safely carry or tow. Items like vehicle structure, chassis and suspension design, engine type, axle ratios and other mechanical variables are taken into careful consideration when engineers create these vehicles. Overloading a pickup could cause significant safety concerns since the brakes, axles and frame may be jeopardized if the operator is unaware of the safety limits.
Calculating the normal safety limits of your pickup is normally straightforward; you add the weight of your passengers and the weight of your cargo (typically loaded in the bed) to the weight of your pickup (assuming you know the truck's actual weight — don't simply rely on what the manufacturer or salesman tells you). You want this combined number to be below the stated GVWR (found on the doorjamb) for your specific vehicle. If you're towing, remember to add the tongue weight to the GVWR calculation.
When figuring out what you can safely tow, take the GCWR of your truck (a number not always posted on the doorjamb), subtract your truck's weight, the cargo and passengers you're carrying, and the remainder will be the amount of weight you can safely tow.
That all seems like some straightforward math; however, finding out your exact elevation or looking at what elevation gains you may encounter that could lower your GCWR (and quite probably your GVWR as well) 2 percent per 1,000 feet is not common knowledge. Plus, while 2 percent may not sound like a lot, it can have a substantial impact.
A Quick Example
The maximum GVWR of a 2015 Ford F-150 regular cab with a 5.0-liter V-8 engine is 7,850 pounds. The maximum payload is 3,300 pounds for a two-wheel-drive truck with the Heavy Duty Payload Package and 18-inch wheels. That means our F-150 should weigh 4,550 pounds: GVWR minus payload equals truck weight. Most other F-150 setups without the Heavy Duty Payload Package can carry between 1,580 and 2,330 pounds.
At 11,000 feet, like when driving through the Eisenhower Tunnel just west of Denver, our factory-rated GVWR could drop, if using Ford's recommendations, by as much as 20 percent. This means a truck with a payload of 2,330 pounds would need to drop 466 pounds. A truck with the Heavy Duty Payload Package would need to reduce its GVWR by close to 700 pounds.
Maximum towing capacity at that elevation would, of course, also drop as well. Using our same example of the Eisenhower Tunnel and the truck's maximum tow rating of 12,200 pounds — a two-wheel-drive F-150 equipped with a 3.5-liter EcoBoost V-6 and a 3.55:1 rear axle — the towing capacity could drop almost 2,500 pounds when going through the tunnel.
Other Truck Manufacturers
Looking at other manufacturers' owners' manuals, we couldn't find a single reference to reducing hauling or towing capacities at various elevations, so we contacted each pickup maker to find out why.
Chevrolet Truck Manager Tom Wilkinson told us, "Engines do lose some power with altitude, but we have sufficient reserve to handle the payloads and trailer weights at which we rate the trucks."
Nick Cappa of Ram communications said, "Ram is the only pickup manufacturer to use SAE J2807 towing criteria for all three full-size pickup truck segments, and we do not reduce the towing or payload capabilities of our pickups as elevation increases."
Nissan states in its owner's manual that engine performance will suffer at higher altitudes, but says nothing about towing or hauling: "An engine will lose about 4% of its performance for every 1,000 feet above sea level that you travel. If you will be towing in high altitudes, it is a good idea to allow more time than usual due to the engine's reduced performance."
Steve Parrett, manager of Nissan's southeast and south central region communications, said the performance loss applies "specifically for naturally aspirated" engines and Nissan does "not place any restrictions on GCWR as a result of elevation change."
We couldn't find any such note in the 2016 Toyota Tundra owner's manual, and when we contacted Toyota we were told the pickup's towing capacity is not affected by altitude.
No doubt we'll hear more about this issue from Ford and the other manufacturers. In the name of full disclosure, we did contact SAE International several times but have yet to hear back.
Cars.com images by Evan Sears
Comments
Altitude will not affect anything but power levels. It will have no effect on the safety items like braking and handling.
Oh Ford said this if coarse it should be the law of the land at least that's how this Ford site works.
Wow. Fiat's propaganda guy talks just like their fans on here! Toyota was using J2807 waaaayyyyy before Fiat. They finally started using is YEARS later. Their statement is as lame as something like, "we have the fastest and most capable pickups that use coil springs and Mexican made engines."
Another advantage to turbocharging.
@Dav
Nick Cappa of Ram communications said, "Ram is the only pickup manufacturer to use SAE J2807 towing criteria for all three full-size pickup truck segments...
Note the all 3 full size pickup segments....
Tundra only has one fullsize segment
but i still would buy a ram ever.
The trucks that aren't towing shouldn't take a hit in the payload department as the GVWR determine that is much less than the GCWR. My 2010 Raptor has a GCWR off 12300lbs and a GVWR of 7100lbs. At the Ike tunnel it will loose 22% of its GCWR making its new GCWR 9594lbs. Still above the weight rating of the truck itself. However Raptors are limited in towing to 6,000 lbs by suspension and tires which remain constant at altitude and uses the same drive train avalible on other f150s.
Ford sucks.
f-150's are trash. That CAR motor they use does not belong in a truck.
Since the air is thinner, there is less engine overrun braking.
Ever notice when tflt guys do there Ike tests those NA v8's just scream up there at high rpms and constantly shifting while those little ford v6's just lope along at a low rpm with no to little shifting while pulling that hill better then the v8 rivals???
yeah and the 3.5 eco got 3.3 mpg towing up the ike vs those screaming v8 getting 4.3 mpg there is no eco in the eco boost once the boost starts the eco goes in the toilet
@Scott because of Forced Induction, and if I recall correctly none of the trucks had problems going faster than the minimum posted speed limit on the highway. The Ecoboost Ford was sitting mid-range (where it makes its power). The video of the 14 Tundra and Ram Sport towing the big Lincoln, both sat ~4,000 RPMs for the majority of the trip, in the video I saw. I don’t consider that “screaming”, seems pretty typical for a NA gas job.
The 6.2 Silverado videos I saw made it seem like GM went full retard on the transmission tuning and it kept dipping low then downshifting to red line then back to a low RPM upshift. I believe the 8 speed fixed the majority of the issues that old 6 speed had with these engines.
There are so many variables in those videos, as they stated, like traffic, weather conditions. You honestly can't compare the numbers. It’s more of a watch how each individual truck handles “REAL WORLD” towing conditions. I think it is more impressive to run into traffic and see how the truck accelerates back up to speed with a load and at that high of elevation.
I also recall the Ford got the worst MPG, in nearly every towing comparison I’ve ever read, thanks to those thirsty turbos.
Skeeter, what the Ike Gauntlet test fails to mention is that if one truck gets the load up the hill at a higher speed, then the fuel economy test is no longer fair. Of course you would burn more fuel if you get the job done quicker. They should do two tests: One at the fastest speed possible, and the other with the faster vehicle matching the acceleration and speed of the slower vehicle to compare fuel economy.
@skeeter
Your statement is incorrect. Ecoboost would get better mpg's if they went as slow as the others. The 2.7 used the same fuel as a 2015 6.2 with same weight in tow while doing it faster.
http://www.tfltruck.com/tfltruck-hall-ike-gauntlet/
Watch the videos comparing the Ram ecodiesel vs the Ford 2.7. That ecodiesel is a huge disappointment in power compared to the 2.7. I would have bet the Ram would have been better than it was by far.
I couldn't find a similar warning in my 2010 F150's manual. It does make sense to reduce weight. My manual did explain GVW and what factored into cargo capacity.
I also recall the Ford got the worst MPG, in nearly every towing comparison I’ve ever read, thanks to those thirsty turbos.
Posted by: john | Sep 11, 2015 11:01:09 AM
That statement is a fallacy created by fan boys
Look at the graphs in this link on towing.... There is a little bullet below the towing graph where the 3.5 Eco pulled 6800lbs in this tow test.
http://special-reports.pickuptrucks.com/2015/01/2015-annual-physical-fuel-economy.html
These are the v8's in the same test towing 6700 lbs in the same time frame on same route.
http://special-reports.pickuptrucks.com/2015/01/2015-light-duty-v-8-challenge-fuel-economy.html
Ford owners are the only owners stupid enough to have to be told this.
Ford owners are the only owners stupid enough to have to be told this.
@Dav
Toyota was using J2807 waaaayyyyy before Fiat.
Toyorust started back in 2011 to use J2807 and Dodge back in 2013 is it waaayyyyyyyy before Dodge men go back to school and leave the men alone.
Go suck a lolipop in your Toyota bed.
@Scott not sure what you are even trying to prove. One link is to the V6 engine test, and the other is a V8 test. The only time Ford wasn't at the bottom loaded/towing a trailer was when it has the NA V8 5.0. I'm thinking you have no idea what you are talking about.
I think you failed, or copied the wrong link….
@ Scott this is really the test you should have used, since it has the ecoboost and the V8 trucks... Look at Ford, good unloaded MPG and crappy towing MPG, just like Ram.
http://special-reports.pickuptrucks.com/2013/06/2013-light-duty-challenge-mileage-drive.html
@john
The annual physical test and v8 test were performed at the same time. It's even stated in the test that the 3.5 pulled what the v8's did so they could compare to the v8's. They could just move there data around the graphs. It is very relevant in mpg's towing.
Also John the link you posted both gm's had the 5.3 and look how horribly slow they were in the test. If they slowed the ecoboost up to the dismal speed produced by the gm's in the link the ecoboost would get better mpg's do to going a lot slower.
As air density decreased with altitude a turbocharges must spin faster to pump the equal amount of air to the engine.
The NA engine will suffer largely at altitude. It would also be hard to give a definite number on the loss of a turbocharged engine accurately as a NA engine. As stated a 4% loss on a NA engine is more or less a given.
The turbo engine will depend on turbo efficiency.
I think you'll find on multiple turbo engines the losses will be lower at altitude. The 3.5 Ford EB isn't a multiple spool engine as it has a dedicated turbo for a set of cylinders.
Big Al,
"I think you'll find on multiple turbo engines the losses will be lower at altitude. The 3.5 Ford EB isn't a multiple spool engine as it has a dedicated turbo for a set of cylinders."
The 3.5 and 2.7 EB engines both have 2 turbos one mounted on each manifold. Both turbos are plumbed together into the intercooler. They do not run independently of each other. Both feed into a collective and act as one once compressed air enters the single intercooler and onto the throttle body.
I wonder how much this has to do with the examples we see on the internet of guys having their ecoboost engine grenade at high altitude?
I recall two forum threads of high altitude motor loss. One f-150 was multiple times.
http://www.f150forum.com/f70/first-time-my-eco-blew-up-208912/index2/
A lot of talk about altitude and turbo spikes on these motors....
Ha,Ha,Ha, another way Ford has boosted their numbers on paper until you read the fine lines. lol Think j2807
Ford does not recommend a V6 for frequent towing. That's what their 5.0 is for.lol
HEMI V8 - look at all of those Ram recalls. NHTSA does not recommend Ram for anything other than scrap.
Hemi,
the F150 is already J2807 compliant. http://www.ford-trucks.com/articles/towing-the-standard-ford-to-adopt-sae-j2807/
In fact when the F450 Superduty ( not the chassis cab) was tested Ford was told to raise the GCVW because it was actually stronger than what Ford was certifying it for. I would love to see where Ford says the 3.5 is not for frequent towing
Altitude will not affect anything but power levels. It will have no effect on the safety items like braking and handling.
@John
You were kidding, right? Tow ratings are meaningless without a regard for the performance of chassis, steering and especially brakes.
None of these components are able to perform at spec if the truck is driven down a steep grade with a lot of turns. Even more concern if road surface conditions are not optimal, i.e., ice, snow or rain.
But you were kidding...
While I understand that the author is using approximate figures for their calculations for the purpose of this article, once again why isn't PUTC demanding that all truck manufacturers post the ACTUAL curb weight of the particular truck on the door jamb? If I'm not mistaken the door jamb uses a generic value of the GVWR which does not take into account the difference of all the options added to a truck. Maximum Payload is a generic figure too, so when subtracted from GVWR you're only getting an approximate figure. If you're out several hundred pounds in your actual loads it could mean extra wear and tear on drivetrains and possibly lead to unsafe conditions-I don't want to be the guy who gets clobbered by someone who overlaoded their truck and couldn't stop in time or lost control. It should be a fairly simple matter for truck manufacturers to weigh each truck as it comes off the assembly line and affix an accurate curb weight decal. This takes into account the weight of each and every option added to the truck-a fully optioned truck is going to weigh more than a stripped down base optioned model-what is the exact difference? 100lbs, 300? 500? I don't know and neither does the owner unless they take the truck to a scale and actually weigh their truck. While for some towing very light trailers this may not be significant, for others who are determined to tow loads at the maximum limit rather than get a more capable (and safer) truck the difference could be very significant. In any event , posting the Curb Weight on the door jamb takes all the guess work out and makes calcualting max tow and payloads simple.
That's been in ford owners manuals for over 20 years. The gvw wont change so I don't know why you said it will reduce carrying capacity. The towing is a different story.
Ford has to list this because they are rating their trucks to their absolute limits. It will be interesting and likely entertaining to see how their micro-engines that are boosted to the max are going to perform with a little age. It would appear that Ford is validating this because there are so many other elements to consider when setting a tow rating. It could be that the aluminum becomes brittle as air pressure and temperature decline with elevation too. Living up to a name: Found On Road Dead!
The simple answer to the headline question is, "Yes." While high altitude may have no effect on the carrying capacity of the vehicle, if your engine has 20% less power at altitude, you're simply not going to have the oomph to get over that hill (mountain) as it would at sea level. That is, after all, why the PUTC shootouts tend to include the Eisenhower Tunnel climb as one of their tests. Yes, it CAN make the grade, but as is very obvious especially in their videos of the trucks, they simply lack the power to maintain highway speed UNLESS they're turbocharged.
Just remember to let that turbo cool down before you shut off the engine after a workout like that.
The simple answer to the headline question is, "Yes." While high altitude may have no effect on the carrying capacity of the vehicle, if your engine has 20% less power at altitude, you're simply not going to have the oomph to get over that hill (mountain) as it would at sea level. That is, after all, why the PUTC shootouts tend to include the Eisenhower Tunnel climb as one of their tests. Yes, it CAN make the grade, but as is very obvious especially in their videos of the trucks, they simply lack the power to maintain highway speed UNLESS they're turbocharged.
Just remember to let that turbo cool down before you shut off the engine after a workout like that.
Dan, it is obvious that you have very little knowledge when it comes to trucks and especially engines. Your comments are just way to funny to be accurate. The boosted 2.7 and 3.5 are far from their limits when it comes to making power. The bottom ends are built very robust with the 2.7 being made of the same material as Ford, International and some Cummins engines. When you build a bottom end similar to a Diesel you get diesel like longevity. I know several construction companies that us the 3.5 powered trucks for heavy work and they all have over 200k on them with some pushing get 300k. No major or real minor issues to speak of. Just regular PMs.
Your comment on aluminum is just to stupid of a post.
These wide open full load tests up the hill are meaningless. Reduce speed while climbing large elevations, especially near max tow/load, its the smart thing to do, for wear and tear, FE, safety.
What did people do 20 years ago when these trucks had over 100 less HP??
This is all for bragging rights, when you clear away all that BS and know you shouldn't be at max load tow on a light duty truck anyways, at least not on a regular basis, the fudge factor should be 10-20 percent less than advertised max tow/haul.
If you are going to be routinely using a truck at max tow/haul and its a half ton, its time to move to an HD, its not like the HD's cost that much more and are WAY more capable.
I'd be fairly certain that Ford puts that note in the owners manual for liability reasons. Maybe they've been sued by someone who had an accident with an overloaded truck and thought he could milk the system. So now Ford gives warnings so when some idiot tries to sue, Ford can say, "Look, we warned you that you shouldn't tow as much at high altitude, if you want max performance when towing you should use premium fuel," and the list goes on. You can thank our idiotic law system that allows people to do retarded things and then put the blame on someone or something else instead of taking responsibility for their own actions.
@Dan Ford's 3.5L and 2.7L ecoboost engines are not boosted to the max. They run an average range of 12 psi of boost, which is no where near max!!!!!!!!!!! Considering the blocks are made from high strength aluminum alloys (3.5L) and CGI Compact Graphite Iron (2.7L). They can easy withstand higher boost pressures without failure.
All the Ford has to do is tow the loads as slow as the competition and they will get the same or better mileage. The Eco Diesel is sooooo slow your always letting off to stop any other truck from running it over. The GM having gone on full retard trans programming wide should have their trans team taken out and shot for such a foolish blunder.
The Eco Boost is the best performing tow truck, the 2.7EB just layed a beating on all the latest and the greatest on TFL Truck, a real world test. Even the haters had to agree, it had the best mileage empty and mid pack hauling a lot faster and better!~!~
Ford has been honest enough to make those claims while towing better than any other truck on the planet...Maybe the only honest truck manufacturer.
By far the most exotic truck and most luxurious truck on the planet. Twin Turbo engines, Mod 4 valve/quad cam engines all aluminum body, with the most available options and more configurations than any other truck on the planet!!!
Im pretty confused. I used to haul a heavy old school horse trailer, loaded with 2 1000-1100 horses up and down the mountian roads of San Bernardino in my 1995, F150 inline 6, manual transmission and never had a sputter , loss of power or overheating problem. Yet, I am reading, many folks with stronger and newer vehicles are experiencing issues while driving high altitudes without tow loads comparable what I was hauling. Can somebody enlighten me? I frequently went above the 7,000 foot altitude level.
Linda,
there is a loss of HP at higher altitudes because the air is thinner. Thin air means less available air that can enter the combustion chamber. Turbo Charged engines have some reduced power but not as much as a normally aspirated engine. Some of the newer trucks like the F150 and Superduties and Tundra have met the J2807 tow ratings that indicate that they can maintain a set speed up a specific hill. So as long as they can climb that hill under max load flat ground would be much easier for the vehicle. Those 300CI engines would not break any speed records but they would tow for sure.
Having lived in the Andes, where you can end up driving at 19000+ feet above sea level. An old F150 with a carburator would actually perform considerably better than a current Silverado or Dodge truck.
Not saying that Ford is better, just that a carburator had its advantages as the same would be true for any other carburator based pick up truck. Even the oldToyota Stout could easily tow over 3 tons when it was rated at 2 at 4200 meters (13700ft).
The key was to advance the distributor timing as you increased in altitude. This allowed the engine to perform a lot better than at sea level. It was like driving on high octane gasoline, the engine also ran a tad bit warmer, because the radiator couldn't dissipate heat fast enough due to the lack of less air mass.
Though for many years now, computers have been running the show, for what was once was a mechanical device. Vehicle electronics are regularly reprogrammed in South America to handle the altitude. (Likely the reason why Peugeot had an advantage during 2016 Dakar that frustrated Gordon's Gordini and Gordon himself).
The real questions we should ask truck manufacturers, are: have they consider this option on their ECUs.? If so, how can we order it? Better yet, why don't they include this as a default option, like Toyota, Nissan, Scania and Mercedes do si in South America?
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