Adequate Tow Vehicle Rating

I’ve seen this subject come up on just about every vehicle forum there is. A basic safe “Rule of Thumb” to use when selecting a tow vehicle is to get/use a vehicle that has a tow rating 20% more then the total weight being towed (this includes passengers and cargo).

Koz

[Mr. Adventure]

Originally Posted by Pitbull

I’ve seen this subject come up on just about every vehicle forum there is. A basic safe “Rule of Thumb” to use when selecting a tow vehicle is to get/use a vehicle that has a tow rating 20% more then the total weight being towed (this includes passengers and cargo).

Koz

Extra capacity is always a good thing. The only limit to tow capacity is cost. At some point there's a balance between what you do and what you won't. Given that ratings are figured differently among manufacturers and model years, a blanket 20% rule penalizes TVs with conservative ratings versus those that were set more aggressively, and it really doesn't address safety or durability questions. Capacity is on the doorpost and in the manual, but safety is out there on the road.

Here's a better basic rule of thumb for safety in towing: "Never drive too fast for your vehicle and conditions." And a close second: "Take a good long look at your tires, trailer, and hitch before you go and at every stop along the way."

[scrubjaysnest]

Originally Posted by Pitbull

I’ve seen this subject come up on just about every vehicle forum there is. A basic safe “Rule of Thumb” to use when selecting a tow vehicle is to get/use a vehicle that has a tow rating 20% more then the total weight being towed (this includes passengers and cargo).

Koz

Putting some numbers to this and one must always be careful with averages.

average TM as reported to the forum 4000# plus two adults, 300 to 400#
Lets say 4400# x 1.2 = 5280# without adding any cargo to the TV. So the TV needs to have about a 6000# tow rating. Sounds reasonable to me as long as Mr A says you can stop it.

Here's a better basic rule of thumb for safety in towing: "Never drive too fast for your vehicle and conditions." And a close second: "Take a good long look at your tires, trailer, and hitch before you go and at every stop along the way."

I agree with Mr. Adventure. Common sense has to be applied to towing and tow ratings.

One of the reasons I purchased a TM was because I could use my daily driver for towing as well. The tow rating on my jeep liberty diesel is 5000 lbs and the max tongue weight is 600 lbs so the TM is well within limits and I get around 22 mpg while towing. If I bought a TV using worst case rules of thumb I'd be driving an otherwise useless (to me) vehicle getting 11 or 12 mpg.

A lot of people wouldn't use this combination because of the jeeps short wheel base but I have towed my 2720SD for thousands of miles through mountains, gusty winds (as high as 50mph), crowds of transport trucks on LA freeways, driving horizontal rain ...and have only a few times felt a push on the steering. I have never had any sway or felt out of control.

There are a lot of factors besides towing rating. I have a weight distribution hitch (with no sway control) and regular passenger tires (Truck tires would be better for squirm but not so good for cost) on the jeep. I keep my trailer brakes adjusted and test them every time I stop for a rest. My trailer tires are 15" and I keep them at 60 to 65 lbs pressure. I never go faster then 65 when passing and usually average 55 to 60 mph on a trip.

We camp in all conditions from snow and freezing to dry desert heat. The only thing that keeps me off the roads is black ice, freezing rain or snow covered surfaces. The tricky thing about winter camping is figuring out when the roads are ok to get from home to the campsite.

Peter

[Mr. Adventure]

Stopping distance is not the only physical factor in safety, but it's probably well ahead of whatever choices we have for second place. I have a friend who owned a trucking company for 20+years. I've posted here before about some of the things I learned from talking to him.

I once asked him if a loaded truck with anti-lock brakes has a longer or shorter stopping distance than an empty one. He said they'd probably come out pretty close to even. In other words, in this offhand estimation, he figures that a semi at 40,000# stops about the same as at 80,000#. So in an extreme example, the 40,000# truck with a GCWR of 80,000# doesn't have a significant stopping advantage to show for it despite being on the road at half its tow capacity.

Having a tow capacity margin for a given load probably has durability advantages, and may allow more relaxed calculations to stay within axle loads, etc. But it doesn't guarantee that you'll be more certain to stop before reaching the scene of the accident (I do like those integrated brake controllers, though).

Originally Posted by Pitbull

I’ve seen this subject come up on just about every vehicle forum there is. A basic safe “Rule of Thumb” to use when selecting a tow vehicle is to get/use a vehicle that has a tow rating 20% more then the total weight being towed (this includes passengers and cargo).

Koz

Heh, our first TV (Toyota Tacoma) had a 6500# tow rating, but a payload of only 1100# which we routinely went over by 350-500# (high tongue weight + lots of gear + people).

So it's not just the tow rating you want to consider, but the payload (and GCWR) as well.



Besides safety, another advantage of an over-rated TV is that it will probably be quieter and less worrisome. The engine will be running at lower rpm, and there will be less shifting involved. Not a big deal if your trips are few and/or short. But if you're retired and spending a lot of time in your TV (making that once-in-a-lifetime tour of the continent for example), an over-rated TV could well be a more comfortable, quieter ride, in addition to the peace-of-mind associated with the extra safety cushion. We've certainly noticed this with our new F150 (Tow 11,300#, Payload 2030#) compared to the old Tacoma (6500#,1100#).

A disadvantage of an over-rated TV might be worse gas mileage (although our F150 is getting about the same mileage as the old Tacoma).

[yoda911]

I am new to the travel trailer world but am seasoned at camping and hauling trailers. From back packing to hunting to hauling horses and hay over mountain passes. I have always been concerned about how much "stuff" I bring camping and how much it weighs. We have been able to keep our TM under 3500lb with proper planning. If we wanted to bring more "stuff" we would have gotten a different trailer and TV. My TV has a tow capacity of 3500lb but the same HP, torque, wheelbase, transmission and coolers as some vehicles that have listed capacities twice that. Having owned a horse ranch, towing was a necessity with 3 F250's and 1 F350 over the years. I understand why some would want a TV with a much higher TC than needed to increase their safety margin but if safety is truly their concern, they would never load the TM over 3500lb. The 2727SD TM axle has a rating of 3500 lb, the brakes are rated at 3500lb and the tires are rated at 3700lb so loading the TM beyond this becomes more of a safety concern that having a TV that is rated right at 3500lb. It concerns me that some will have a huge TV that they say is for "safety reasons" yet grossly overload the trailer axles and trailer brakes then say that those of us towing with TV's rated at 3500lb are unsafe. To be truly safe, always tow with a towing mindset. Inspect all of your components often, keep your speeds down and you following distances up, limit all distractions, both hands on the wheel, anticipate dangers on the road and from other drivers and take your time, enjoy the drive. Remember, its a vacation so enjoy all aspects of it. IMHO

Originally Posted by brulaz

Heh, our first TV (Toyota Tacoma) had a 6500# tow rating, but a payload of only 1100# which we routinely went over by 350-500# (high tongue weight + lots of gear + people).

What year and model had that rating?

I had a 98 that was rated at 5K lbs (tow) and 1650 payload.

Koz

Originally Posted by kokilo

I agree with Mr. Adventure. Common sense has to be applied to towing and tow ratings.

One of the reasons I purchased a TM was because I could use my daily driver for towing as well. The tow rating on my jeep liberty diesel is 5000 lbs so the TM is well within limits and I get around 22 mpg while towing. If I bought a TV using worst case rules of thumb I'd be driving an otherwise useless (to me) vehicle getting 11 or 12 mpg.

Peter

Your set-up is very close to the 20% rule of thumb at approx 4K lbs, with a 5K lbs rating (maybe a little closer to the max rating depending on cargo). With a 5K lbs rating you need to keep an eye on tongue weight.

Koz

[Bill]

Originally Posted by yoda911

My TV has a tow capacity of 3500lb ...

You make some good points. On the other hand, I'm sure you've seen the specs on the Lexus site that say "Max towing 3500 pounds" followed by footnote 7, which reduces that capacity by saying "The maximum you can tow depends on the total weight of any cargo, occupants and available equipment." In other words, rated tow capacity is reduced pound-for-pound by the weight of cargo, occupants, factory options, and aftermarket equipment. This additional weight runs between 500-1000 pounds for most owners. Now where do things stand?

By the way, the Lexus site says the V-6 engine puts out 270 hp, not 370 hp.

Not to be discouraging, but since you live in Denver, you will probably travel at high altitude, with significant up and down grades. That will be a challenge. My wife and I have a cabin in Big Elk Meadows (Lyons, kind of), at 7700 feet. Our Explorer (7000 pound tow capacity), with the TM behind and probably 800 pounds of "cargo, occupants, and other", is always a bit reluctant, as we make the long steep climb to the gate from either direction. As a quick check, you might want to put a tranny temp gauge on your Lexus (they require only a quick electrical plug-in - no plumbing - and not too expensive), load up the Lexus and the TM ready for camping, and drive up to the gate at Big Elk. Take CR47 off Rte 36 between Lyons and Estes Park. You may be surprised.

Bill