Towing capability is something that truck and SUV manufacturers love to brag about, but what is it, exactly, that gives these vehicles the ability to safely handle a heavy trailer? The size of a tow rig is certainly one factor, but there are many other things that come into play when hauling that all contribute to a safe and efficient experience on the road.
Cooling, Cooling, Cooling
If there’s one thing that’s universally true about pulling a trailer, it’s that it puts a serious strain on your vehicle’s driveline. In order to improve towing capability, most of the tow packages that you’ll find on an automobile’s options sheet include heavy-duty cooling systems. Moving more weight causes an engine to work harder, which, in turn, demands a bigger radiator, as well as additional radiators for the vehicle’s oiling system and transmission fluid. You may even see a “finned” differential cover on tow vehicles that helps keep differential fluid from frothing due to overheating.
Adding more weight in the form of a loaded trailer doesn’t just place extra demand on your motor, it also calls for additional firepower when trying to stop. Towing capability is determined not only from a car or truck’s horsepower and torque rating, but also its braking, which explains why towing packages also typically include upsized front pistons, larger rotors and more heat-resistant brake pads. Some modern vehicles also include a trailer sway control option that uses an anti-lock braking system to keep what you’re towing from fishtailing, which can be especially helpful when towing in slippery conditions.
It used to be that if you wanted to be able to control your trailer’s lights or brakes from inside the cab of your tow vehicle, you had to buy and install an aftermarket system. These days, there are many trucks and SUVs available with integrated trailer brake controllers and factory-wired lighting harnesses. These aren’t luxuries; they’re actually two great ways to make sure that you have consistent, controlled braking for your trailer and bright illumination, so that everyone behind you can see that load you’re towing.
It’s never a good idea to leave anything to chance when deciding how much you can safely tow with your car or truck, especially if you’re just getting started with trailering. Make sure that your cooling, braking and integrated systems are up to the task before you take that load out on the road.
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Photo courtesy of Morguefile.
Having been bitten by the car bug at a young age, I spent my formative years surrounded by Studebakers at car shows across Quebec and the northeastern United States. Over ten years of racing, restoring, and obsessing over automobiles lead me to balance science writing and automotive journalism full time. I currently contribute as an editor to several online and print automotive publications, and I also write and consult for the pharmaceutical and medical device industry.