By BoatUS Trailering Editors
It’s been called a classic chicken-and-egg story: You buy the boat and then you look at your tow vehicle. Not good. Not good at all
A family found “the perfect boat” and brought it home on its brand
new trailer from the dealer. They were new to boating and eager
to learn everything they could. Things went fine until they tried
pulling the boat up the ramp after their first day on the water. The
truck’s engine was straining and the rig was moving very slowly.
Seeing a problem, a couple of boaters came over to lend assistance and told
the new owner, “Nice boat, but your truck’s too small.”
“Whaddaya mean ‘too small’?” the new boater asked, looking at his freshly waxed truck. One of the guys took a deep breath and said, “OK, we’ll do it this way. Truck’s just fine. It’s the boat that’s too big.”
To help readers avoid making the same mistake, BoatUS Trailering gathered some tow vehicle experts to respond to four possible excuses, many of which are common on boat trailer blogs and websites, the boat owner may have used.
We spoke with former Toyota and Hyundai engineer and now director of vehicle testing for www.Edmunds.com Dan Edmunds (no, he's not related); Dave Sowers, marketing manager of Ram Trucks; Mike Levine of Ford F150 trucks; and Robert Krouse, trailering engineer for GM North America.
"All I need to know is the tow capacity"
Krouse: You have to know what goes into that number. Look at your boat weight and then you'd better be sure that weight includes not just the boat itself, but the trailer it is on, and all fuel and gear carried in it. That's called the GCWR or Gross Combined Weight Rating. Lastly, you had better be used to driving with the boat in tow and know how it will respond in various situations.
Sowers: If tow capacity is the only thing they know, they are going to potentially make a mistake because a lot of people go boating and take more cargo and more people, and the weight changes from when they tow it away from the dealer in its completely dry state to when it?s full of fuel and years? worth of snacks and life preservers, and so on.
“I only pull the boat a few miles to the ramp.”
Krouse: Sometimes, interstate driving is the easiest. Sure, the engine and transmission won’t overheat on a short trip to the launch ramp, but that trip probably has some stops and turns, and maybe even some grades (hills). Braking and handling capability — which are key factors in the Gross Combined Weight Rating and Trailer Weight Rating [TWR] — come into play. Braking and handling incidents can occur suddenly under virtually any circumstances, so you’d better be sure your tow vehicle is up to the task.
Levine: Your tow vehicle is just like any tool you use. Unless you’re familiar with how it works, what its strengths and weaknesses are, how to properly operate it, you can do some serious damage.
"What's an axle ratio and why should I care?"
Knowing Towing Tip:
The weight of the fully loaded tow vehicle, and trailer and
boat, and engine, and everything being towed is known as the GCVW (Gross Combined
The GCVW must always be lower than GCWR (Gross Combined Weight Rating).
Levine: The higher the axle ratio, the easier it's going to be for the tow vehicle to get going with the boat and trailer in tow. The Ford F150 has a choice of five axle ratios, but each is designed for a specific model. They range from a low of 3.15 to a high of 4.10 on our 6.2L V8. The average ones are a 3.55 or 3.73 axle ratio. Axle ratio is important, but with today's 6-speed transmissions, the importance is less of a factor than it once was when we were using 4-speed transmissions. Ford went to 6-speeds in 2009.
Edmunds: There's no standard number of axle ratios. It's part of a system that includes the diameter of the tire and the kind of transmission. The downside is that the higher the axle ratio, the lower your gas mileage is going to be.
"The tow package is a waste of money."
Sowers: Most people are familiar with watching their engine temperature when it's hot outside and they'll see the temperature climb a little, whether towing or not, and the hottest temperature is when they're on grades. What they don't think about, though, is transmission cooling and when towing the heaviest of loads where there's frequent shifting on grades. That's when the transmission temperature will increase, so it's important to have that additional cooling capability in a tow package so that your transmission doesn't overheat. It has automatic transmission fluid that is circulated to an external device, or in some cases it's integrated into part of the radiator. Some tow package choices include the option to select a different axle ratio.
Edmunds: With new vehicles, if you just click it into "tow haul" mode, it's going to take care of that. With the tow haul feature, the shift schedule and the lockup characteristics of the torque converter change so it's more positive with less slippage, which is good for transmission cooling and reducing heat buildup.
You'll see the tow haul feature on almost every new truck that's available these days.
New Testing Coming Soon To A Tow Vehicle Near You
It’s always been an exercise in “macho” for truck manufacturers to announce the towing capacity of their new vehicles because the next step is to point to the competition and say, “We’re better than those guys.” While the bragging will continue on television, every tow vehicle and car is going to be measured in the same way beginning with the 2013 model year. It’s called J2807 and here’s what you need to know from someone in the middle of the new testing — Robert Krouse, GM North America Trailering engineer and SAE Tow Vehicle Trailer Rating Committee chairman:
How did you come
up with J2807?
There is no significance to the name J2807 — just the numerical order SAE (Society of Automotive Engineers, who set the guidelines) used to assign document numbers. The actual committee name is SAE Tow Vehicle Trailer Rating Committee.
Why do we need it?
J2807 allows a boat owner to more easily compare potential tow vehicles — each OEM (Original Equipment Manufacturer) is using the same tests and same performance requirements to determine trailer weight rating — so an 8,000-pound trailer weight rating on Ford F150, Toyota Tundra, Chevy Silverado, Ram 1500, or Nissan Titan should mean the same thing. There are obviously still differences from one truck to another, but the way the trailer weight rating is determined should no longer be one of them.
Is every manufacturer
Six OEMs have supported the SAE Tow Vehicle Trailer Rating Committee work for at least a few years, and two more have begun to support the work in the last year. All tests, including the one done at Davis Dam, part of Arizona Highway 68, apply to all tow vehicles — trucks, SUVs, crossovers, and cars — from all manufacturers, but each OEM will use its own proving ground resources for all other tests.
This sounds like
are used as well
as on-site locations
like Davis Dam,
Simulation and analytical methods are key enablers for vehicle development and validation today so it is entirely appropriate to allow those methodologies when working toward SAE J2807. However, if both methods are used, physical test results take precedence.
How much weight
is towed in the test?
It depends upon the GCWR and TWR (trailer weight rating) of the tow vehicle being tested, but for a one-ton truck, it could be in the 20,000- pound range. Many pickup trucks, even half-ton models, may be trailering more than 10,000 pounds. The Davis Dam incline is almost 12 miles long and averages about five to six percent with a few locations, mostly near the top, that are about seven percent. It’s a 3,000 foot altitude difference between the top and the bottom which is a reason this site works for us. This is used for highway gradability and thermal performance, but there are other propulsion tests for launch and acceleration run at provingground sites. The thermal performance run at Davis Dam is done when the outside temperature exceeds 100 degrees and each truck has its air conditioner on high.