Should I pay extra for trailer electronic anti-sway systems if I have TSC on my towcar?

This is a question I am getting about once every two weeks now, and it’s impossible to answer because there’s a sliding scale of cost vs risk reduction. In all aspects of life we make a tradeoff between safety and convenience/cost – for example we cross roads away from pedestrian crossings. Cost is a factor too – many of us could replace our cars with safer versions, or option more safety gear, but we don’t because our perception is it’s not worth it. When we go remote travelling we could take a satphone, sat messager and HF radio so we have multiple systems…but most of us draw the line at cost and take just one. We take at least one spare tyre, and many insist you should take two. So why not three? Or four? And so on.

Humans are terrible at assessing risk which is why we’re terrified of sharks and snakes, but blase about driving and roads.

Back to the trailer systems. In the video below you’ll see two basic types explained; car and trailer. They are complementary and non-exclusive, which means that if you have both they work together, but each by itself can work too. All the car systems are essentially the same thing, but there’s two types of trailer system. Regardless of the system, all do the same thing, which is detect sway and apply brakes to fix it.

At this point I need to emphasise that you MUST set up your trailer properly so that such electronic systems never need to operate. This is mostly about weight distribution, but also tyre pressures and hitch height – working on the latter now, stay tuned for a video. Weight distribution in a caravan is hard, and mostly about not making it worse.

So back to the question. Do you *need* one or the other? Well chances are your towcar has car-based TSC already, so that’s taken care of. Do you need to add it to the trailer as well? Hopefully by now you realise that’s an impossible question for me to answer. Would it reduce the chances of a sway-crash? Yes, definitely. Is the reduction in risk worth the money? I can’t say, all I can do is give you the base information for you to make that call. One other point to consider is relative weights; a 3000kg “offroad” (lol) caravan on muddies towed by a 300,000km old LC200 on worn rubber with original suspension is more likely to sway than a 1000kg camper trailer towed by an LC300 with all new gear.

Further complicating the matter is where else you could spend the money you would have spent on trailer sway systems; for example modifying your trailer for better weight distribution, or putting it towards a better towcar.

We are seeing trailer sway systems fitted to more and more trailers as standard or an option, and I applaud those manufacturers who are taking this important safety step – thank you – so long as it’s not there to mask inherently poor stability.

Your caravan insurance may also be lowered a little if you have TSC on the trailer, although it would be quite a few years before you break even.

There is, sadly, a lack of empirical research on trailer dynamics – how they behave with different weights, speeds, towcars etc. I’ve spent years looking for it and there’s very little. My dream is to get funding to properly explore trailer dynamics and make the results freely available so we’re all safer, but I need a few million more views on YouTube and a few thousand more Patreons before I can think about funding that!