Trailer towing Range

[Luke42]

Not being a truck, towing, or RV kinda guy, I have a question along these lines. If a vehicle gets X range from its tank/battery, and there is a Y% penalty for towing a given trailer. Shouldn’t the penalty be the same for ICE or EV? Same aero, same amount of energy required. Sure, with ICE you have “in/out of power band” issues with underpowered tow vehicles, but it would seem the penalty there would be worse on an ICE vehicle. I thought I read that someone on a thread said EVs were worse at towing penalty, but I don’t see why. Please enlighten me.

The trailer doesn't care what kind of engine is pulling it. It just resists motion due to intertia, aerodynamic drag, and rolling resistance.

From that perspective, the 50% range-hit (MPG reduction) that I take from towing my travel trailer with my ICE truck should be roughly the the same with the Cybertruck.

What makes it complicated are:

• The more efficient the truck, the bigger the range-hit the trailer creates. The trailer's efficiency is fixed so, if you swap in an efficient truck, it'll lose more range pulling the relatively inefficient trailer. We won't really know how well this works until someone tries it.
• Quirky edge cases in drivetrains can cause certain combinations of speeds and loads to be more or less efficient. This is particularly true in ICE vehicles which have engine-sweet spots and multiple fixed gear ratios -- but they can theoretically happen with hybrid and EV vehicles, too. We won't really know how well this works until someone tries it.

Given that we have Cybertruck sightings daily now, but that they never include trailers, I'm starting to wonder if this thing is really being developed as a tow vehicle. We won't really know how well this works until someone tries it.

Back to the towing range-numbers, I mentally divide the range number by three to guess what the towing range of the Cybertruck will be with my travel trailer. It's a wild guess, but it's the best guideline I've got until someone does a range-test with the Cybertruck pulling a travel trailer the same size & shape as mine.

That means I'm really hoping "500+ miles" really means "620 miles", but we won't know until the specs & pricing are released.

Towing would be a big part of my justification for owning a Cybertruck, so I'll be waiting for someone else to really put it through the towing ringer before I buy. And, honestly, the inevitable Tahoe-sized 3-row SUV/van variant of the Cybertruck might fit my use-case better anyway.

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[cvalue13]

Shouldn’t the penalty be the same for ICE or EV? Same aero, same amount of energy required. Sure, with ICE you have “in/out of power band” issues with underpowered tow vehicles, but it would seem the penalty there would be worse on an ICE vehicle. I thought I read that someone on a thread said EVs were worse at towing penalty, but I don’t see why. Please enlighten me.

at a “population” average, that’s pretty much it

so why do people worry?

because current BEVs have the equivalent of tiny gas tanks, and few refueling stations.

take my Lighting F150 range compared to the most fuel efficient F150 range, and you’ll find that my Lightning has the equivalent of a tiny 13 gallon fuel tank.

an ICE truck with a 13 gallon fuel tank would also cause range anxiety when towing and experiencing 50% range loss - with the exception that gasoline stations are found every 20-30 miles.

basically, in terms of tank size/infra range constraints, BEVs are presently equivalent to say ICE trucks towing in the ~1960s, when trucks had smaller fuel tanks, and gas stations were more sparsely distributed.

(when today people say things like “BEV trucks aren’t ‘real’ trucks because they can’t tow far,” it’s the same as saying no truck that existed in the 1960s was a “real” truck - an irony that highlights the actual issue: tank/infra constraints, not energy source.)

all that said, as others have pointed out, there are some functional differences that result in different constraints or bobbles in the math for a given example. But for every occasional advantage area of ICE (eg efficiencies at a certain power bands), there can be occasional advantages of BEV (eg existence of regenerative breaking)

But as BEV tank/infra improves, they’ll quickly catch up to then surpass ICE for towing: once range is solved, BEV’s torque and performance far outperform ICE when towing.

At a simplified reality level, this engineering explained video does a good job:

If the f150 lightning halves its range while towing, the CT will loose more because it will rely more on aerodynamics to achieve its baseline range.

this above is a reality of the physics involved that I’ve seen few appreciate

while it’s not a foregone conclusion, it’s entirely possible (if not likely) that the CT is effected by towing more than the Lightning

the Lightning’s base range of 320mi reflects its poor aerodynamics (and basic rolling resistance). Put that identical Lightning powertrain in the CT aero envelope, and directionally it may be a 450mi range combo.

conversely, put a 500mi CT powertrain in a Lightning envelope, and it may be a 320mi range combo.

for the same reasons, put an identical trailer behind each of the Lightning and CT envelopes, and the range effects will be different - generally, worse for the CT

All else equal, the Lightning’s relatively poor aero mean it’s busting up the air in front of the trailer, reducing the relative drag of the trailer; while the CT’s relatively good aero mean the trailer will proportionately incur more drag from needing to bust up the air that much more.

All else may not be equal, and it isn’t necessarily a foregone conclusion depending on whether the CT deploys some particular technology to minimize this effect. But if so it will be at the margins, and mitigation of the basic physics at play

it’ll be a wait and see how the CTs towing performance compares in terms of range effects - the same qualities that result in unladen range stats may be what also emphasize the effects of towing.

 

[kev12345]

If the f150 lightning halves its range while towing, the CT will loose more because it will rely more on aerodynamics to achieve its baseline range. Obviously when towing, aerodynamic advantages are thrown out the window.
I have towed things with our model y, and I tell you first hand that you will be doing a lot of patience training towing with ANY ev.
I think there’s gonna be a lot of disappointment out there when people start hitching up.

just assume you'll lose 2/3 of your range right now and you won't be disappointed later! hopefully the delivery event comes with an announcement of more pull through superchargers.

 

[Crissa]

The more aerodynamically efficient truck might lose more range. There's also a bit of a shadow effect from the disturbed air behind the truck, but the trailer might do better behind a the more efficient truck back it's not baffling (the low pressure waves collapsing repeatedly) as much.

Also, the more efficient truck might have more efficient cooling. motor controller energy conversion, better regen control, more deft control of the trailer braking, or not need as much braking due to all-wheel steering giving better control over the trailer.

There are so many variables at play. Aero is just the biggest one.

-Crissa

 

[charliemagpie]

Its only a couple of minutes long, for anyone interested.(ICE)

He cuts through the crap regarding wind resistance, and provides a realistic towing range expectation, to maybe temper our unrealistic ones. imo

If course, is it uphill, downhill, wind, no wind? I'll leave that up to the experts here to discuss over the next 1000 years.

 

[JBee]

Not being a truck, towing, or RV kinda guy, I have a question along these lines. If a vehicle gets X range from its tank/battery, and there is a Y% penalty for towing a given trailer. Shouldn’t the penalty be the same for ICE or EV? Same aero, same amount of energy required. Sure, with ICE you have “in/out of power band” issues with underpowered tow vehicles, but it would seem the penalty there would be worse on an ICE vehicle. I thought I read that someone on a thread said EVs were worse at towing penalty, but I don’t see why. Please enlighten me.

Without wanting to repeat what others have already posted, rather to offer a summary; the two main factors that make an ICE truck less affected by towing than a CT are:
- better CT aerodynamics that creates less drag
- and the difference in available energy to propel the vehicle.

The CT displaces air more efficiently because of better aerodynamics, that requires less energy to move the CT the same distance in comparison to an ICE. It could use between 20-50% less energy than a conventional ICE truck.

That means it goes further with less energy, which in turn means it is more sensitive to changes in aerodynamic and weight load, in that a small increase in drag results in a substantial range reduction for the CT.

For comparison the drag created by the CT is the equivalent of a 3x3ft piece of ply board held at right angle to the direction of travel. If you had that sticking out of the bed of the CT, it would also nearly halve the range.

Secondly, A standard ICE truck also has much more available energy in the form of liquid fuel, in comparison to the stored energy in the CT battery. As cvalue13 pointed out, the lightning only has about 15 gallons of useable fuel energy, in comparison to a standard ICE F150 with 40gallons.

Simply, that means that an ICE truck is less sensitive to added drag, and has more energy to compensate for any added drag.

---

In saying all that though is is possible to design a trailer that is aerodynamic, and if attached to the CT in such a way to continue the airflow, without a gap between the vehicles, could result in little extra aero drag. In Europe they already use telescopic hitches on trucks to improve aerodynamics, by pulling the trailer up close behind the truck whilst driving straight. Then telescoping out so that it has enough clearance to turn.

In fact there are already rear cargo boxes that improve EV range, by increasing the trailing length of the vehicle so that airflow is recombined more efficiently. As you would know, an airfoil has a fairly blunt front leading edge, but requires a tapered trailing edge for good airflow.

https://www.topgear.com/car news/thule-arcos-cargo-box-improves-EV-range

 

[Haopec]

If the f150 lightning halves its range while towing, the CT will loose more because it will rely more on aerodynamics to achieve its baseline range. Obviously when towing, aerodynamic advantages are thrown out the window.
I have towed things with our model y, and I tell you first hand that you will be doing a lot of patience training towing with ANY ev.
I think there’s gonna be a lot of disappointment out there when people start hitching up.

The Lightning’s base range of 320mi reflects its poor aerodynamics (and basic rolling resistance). Put that identical Lightning powertrain in the CT aero envelope, and directionally it may be a 450mi range combo.

conversely, put a 500mi CT powertrain in a Lightning envelope, and it may be a 320mi range combo.

Both of these quotes are spot on and from my experience towing extensively with both a 100dMX and the Rivian R1T, I can tell you without a doubt, that the MX takes a lot bigger penalty due to its better aero drag component/efficiency while towing
This does worry me about having a 350-mile "ish" CT that would be a towing range LOSS compared to my R1T, which just gets me to the lake with 15-20% battery. If the CT has anything smaller than a 130-135kwr pack it's a no-go for me, not because of the unladen range, but the towing range hit it will take.
I also was going to link the Engineering explained, that guy is spot on!

 

[ninja6r]

You'd be able to drive 324 miles with that 7,000 pound trailer and 500 pounds of occupants if you maintain 55 mph and we assume a 200 KwH battery.

When I think about towing, the battery size is all I think about. Reading your post, I really hope this is the size they go with for the trimotor. With your math, I would love to tow my 5000 lb trailer close to 300 miles. I don't go faster than 60mph when I tow and you give me hope that I might actually get more than the 220-240 I was expecting.

 

[TyPope]

When I think about towing, the battery size is all I think about. Reading your post, I really hope this is the size they go with for the trimotor. With your math, I would love to tow my 5000 lb trailer close to 300 miles. I don't go faster than 60mph when I tow and you give me hope that I might actually get more than the 220-240 I was expecting.

You and me both.

 

[Sirfun]

It also depends on traffic. Out here my average speed for the last 15 years is a whopping 11 mph. Realize that takes into account LOs Angeles traffic, red lights, stop signs and speed bumps. I gave up my big jetting trailers for many reasons and purchased a utility work trailer that is much lighter and multi purpose.
It’s the stop and go that kills the mileage more than anything. My sprinter diesel 3500 gets 12 mpg. And my Nissan 3500 NG gas gets 6 mpg. Realize at close to 9000 # loaded up with real world LA driving, the stop and go is the reason for poor mileage, more so with the energy required to start the load.

on the highway, I’ve seen the Nissan register 13 mpg while going downhill. I’ve never gone 200 miles on a tank of gas. Right now regular is $4.69 and diesel is approx $5.29.

My Traverse is slightly better at anywhere from 11- 22 mpg city highway.

Traffic is the deal breaker, mixed with weight. Gave up s manual trans back in the early 80’s.

So the CT has to be better than any and everything I presently drive.

Fortunately, my annual mileage is under 6k combined between the 3 vehicles. Welcome to LA.
Rick

This is where vehicles with regen SHINE! I have a PHEV Chrysler Pacifica mini van. We drive it any time we go to LA because the regen makes a huge difference between it and my Avalon. The Avalon can get 31mpg on the open hwy. But driving to LA in traffic I'm lucky to get 19mpg. With the Pacifica the regen is producing energy and storing it in the battery every time I slow down. Then as I'm stuck in traffic, the electric motor takes over. It will get 31mpg in traffic using a combination of gas power and the electric motor, that is getting it's energy from the regen.

 

[ldjessee]

Given that we have Cybertruck sightings daily now, but that they never include trailers, I'm starting to wonder if this thing is really being developed as a tow vehicle. We won't really know how well this works until someone tries it.

This is no longer true, lots of sightings in the last week with trailers.

I am hoping that this forces trailer manufacturers charged an arm and a leg for box on wheels and actually have to do some work making trailers more aerodynamic.

 

[SlegMD]

This is no longer true, lots of sightings in the last week with trailers.

I am hoping that this forces trailer manufacturers charged an arm and a leg for box on wheels and actually have to do some work making trailers more aerodynamic.

I think they’re going to charge for the additional arm and leg you have when they come out with this “trailer”!

But it will be interesting to see what is produced.

 

[Carlfluk]

Has anyone seen anything on the range
of the cyber truck towing a trailer?
I am waiting since 2019 as with many others, But i tow a trailer often on longer trips, But concerned about the range of the CT when pulling a trailer??
I ordered the highest model- guessing it’s the tri motor w 500 mile range (???)
i am hoping that the range won’t be cut in half pulling a 5000lb trailer-
Anyone have any insight on this ???
Hopefully we start getting finally order detail emails soon-
Thanks all

weight is not even half of it - it’s aero.Ill bet pulling 5k of bricks on a flat open trailer massacres pulling a 5k box trailer. I know first hand with my f150…bought a new trailer just 4 ft longer and 1.5 higher and it’s flat not v shaped and it feels like I’m pulling a parachute VS. Before nothjng f

 

[ldjessee]

The V in the front helps very little compared to if the V had been in the back.

I bet the biggest difference is the 1.5 ft taller, sticking even higher out of the 'wind shadow' of your truck.

Think of a rain drop, falling, it is a sphere with a long tail. The only thing that shapes raindrops is air, water tension, and gravity. Hard to beat a raindrop for aerodynamics. That is why so many pioneers in aerodynamics used a rain drop shape as their guide towards aerodynamics, long before computer modeling and sophisticated wind tunnels.

The thing is, aerodynamic trailers would help ICE as well as EV trucks...

 

[PilotPete]

The V in the front helps very little compared to if the V had been in the back.

I bet the biggest difference is the 1.5 ft taller, sticking even higher out of the 'wind shadow' of your truck.

Think of a rain drop, falling, it is a sphere with a long tail. The only thing that shapes raindrops is air, water tension, and gravity. Hard to beat a raindrop for aerodynamics. That is why so many pioneers in aerodynamics used a rain drop shape as their guide towards aerodynamics, long before computer modeling and sophisticated wind tunnels.

The thing is, aerodynamic trailers would help ICE as well as EV trucks...

While you are correct about the tail, the V in the front is incredibly helpful. Having a flat front disrupts any smooth airflow in the first few feet of the sides, and creates a huge high pressure area over most of the front. A leading V will drastically minimize that. As you said, tapered the tail will eliminate an equally large low pressure area across the back. But raindrops are never fully flat across the front.

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