How Can I Tow an EV?
This question has started to be heard more frequently and it will become more important as more of us choose an electric vehicle as our day to day driving vehicle. There are a couple of answers to this question. At the present time, there are no EV manufacturers that have specified that their vehicle is flat towable. Some EVs that were derived from an Internal Combustion Engine (ICE) powertrain, have a front wheel drive electric motor (replacing the gas engine and transmission) and the rear wheels are the same as those used in with the ICE variant. The primary consideration that enters the picture is whether there are any changes to the vehicle that activates the rear wheel brakes when the vehicle is not being driven. My experience with both a 2019 Kia Soul EV and a 2019 Kia Niro EV is that the parking brake does not automatically activate when the vehicle is in ‘Park’ and the ignition is turned off. As with most vehicles, the parking brake can be applied as needed. An electric vehicle has wheels that are directly driven by the electric motor. If it was flat towed, the motor would be spinning when being towed. Without any doubt, flat towing is definitely not recommended or approved. However, while Kia does not ‘approve’ an EV being towed, given the design of the powertrain, if the front wheel drive vehicle is placed on a tow dolly with the front wheels off the ground on a tow dolly and the rear wheels are on the road, then the towing characteristics are similar to any front wheel drive vehicle that is dolly-towed. After carefully checking with our dealer’s Service Technicians which did some review of the powertrains, they concluded we would be safe to dolly tow our 2019 Kia Niro EV.
Rather than rewrite the relevant Blog article again, I will refer you to that article on our website. The relevant article was published and is listed under the date of November 7,2019. It is copied below.
After 50 km (30 mi.) Check Straps
Our first long trip while towing an EV on a Tow Dolly was interesting. Loading the dolly becomes easier as we familiarize ourselves with the process of forming a ‘basket’ of the webbing used to secure the tires. It is an evolving process that is refined each time we load the car. We’ve learned that the 50 km (30 mile) stop to check and adjust the webbing of the ‘basket’ is critical, since after towing the EV for that relatively short distance, the straps are looser and must be re-tightened. While it may seem to be an inconvenience to have to stop to check, it is far better to do so, than to risk having the car loose on the tow dolly. In addition to finding the straps looser, we have had one instance where one strap came off the tire completely and was laying beside the tire on the dolly. Over time we have also refined our method of attaching the straps to the dolly to make them easier to install after the car is loaded and allow the straps to be tightened to secure the car to the dolly. We’ve learned through use, how to install the safety retention chain to the car’s suspension and the dolly frame, so that a loose strap does not result in the car coming off the dolly. A proper inspection at each rest stop is essential, although as we become familiar with the loading and strap tie down procedure, it becomes routine. We’ve also learned that the wiring connection from the EV to the tow dolly need not be very long with about 30 cm (12”) of slack in the wiring sufficient for all turning that the car does while being towed on the dolly.
Add Rear Lighting to Towed Vehicle
We highly recommend the addition of rear lighting on the EV which is connected to the tow dolly’s lighting wiring that in turn receives its power supply from the RV. With this additional lighting, the bright lighting on the tow dolly combined with the LED lighting on the side and rear of the RV, turns that are signalled result in those following us, giving the required space to allow us to change lanes or merge safely.
Braking is Different
Braking is somewhat different when towing with a tow dolly versus flat towing using an independent tow vehicle braking system. The tow dolly has a surge braking system that needs to sense a difference in speed between the towing RV and the dolly, using that surging speed of the dolly relative to the RV to brake the dolly with the EV. This is slower by nature than a typical electrically or air operated tow vehicle braking system. We’ve never felt as if we did not have any tow vehicle braking, it is delayed in applying the brakes when we apply the brakes in the coach and wait for the surge brake to react to the slowing RV.
Avoid Adding Axle Grease
The EV tows well on a tow dolly. We did notice that one side’s axle was warm after towing, with grease strips spread around the radius of a tire. When we bought the slightly used dolly, the previous owner had greased the axles using the built-in hub grease fitting. We had only towed a relatively short distance with the EV on the Tow Dolly, however before our trip and after reading the Master Tow instructions, I decided to re-grease the bearings. After seeing the grease on the tire, and noticing the raised axle temperature, I had the tow dolly inspected by a dealer. The technician replaced the rear seal on the axle (although he admitted that it did not seem to be leaking) as well as the two grease fitting rubber caps. His experience with this brand of tow dolly was that people were excessively greasing the axles (following the Master Tow’s (maker) instructions) and creating the problem we experienced. His suggestion was to forgo adding lubricating grease unless and until there was evidence of grease leakage. In other words, more damage was potentially occurring from over-lubrication than from not lubricating the axle bearing. We will follow this advice going forward.
Load Dolly with it Straight
Another item that we noticed is that loading the dolly should be done after the dolly is pulled straight ahead by the RV and loading on a relatively level road surface. This is important since the EV battery hangs below the floor of the EV and the tow dolly loading ramps can contact the bottom of the battery if not level and straight behind the RV. Once the car is on the dolly and strapped into place there is 5 cm (2 inches) of space between the battery bottom and the loading ramps, which is sufficient to reduce any contact between the two while towing the EV down the road.
These lessons are all part of the learning process that comes with using a tow dolly to tow a vehicle after decades of flat towing many vehicles. Every change in vehicle required some adjustment to the new towing system and vehicle. Changing to an alternative method of towing heightens the changes and extends the adjustment process.
EV Brake Rotors May Corrode
One slight change in the towing procedure, then driving the EV was that after towing on a day of extended rainfall, then driving the EV, the EV hydraulic brake rotors ‘corrode’ (become rust covered) slightly. Afterwards, if the EV braking requires those brakes to be applied, in addition to the more frequently used regenerative braking, there is some noise associated with harder braking the first time the brake caliper pads contact the ‘rusty’ rotors. Under typical EV braking, the hydraulic brakes rarely get much use. The EV uses the regenerative brakes for most of its braking. This is a short term, once or twice occurrence and only after towing in heavy rain.
Remember that Length is Longer When Dolly Towing
The other adaptation to towing using a tow dolly when compared to flat towing a vehicle is the extended distance that the vehicle on the tow dolly is behind the RV. This comes into play primarily when negotiating a tight turn, since the coach negotiates the turn and then it takes longer in distance and time for the towed vehicle to clear the turn and the curb nearby. What this means is that the RV must drive farther in the forward, straight-ahead direction, before turning to complete the turn. It is easy to see in the rear camera and side mirror and it takes only a few turns to adjust to the additional length when driving to accommodate the tow dolly and car.
There is an improvement we made to the Dolly Towing procedure which is set out in out the Blog article published April 23,2020. Check it out on our website. Also check out some of the blog articles about charging an EV while on a trip. Changes are always being made and I’ll be writing updated blog articles as we learn of those changes as they develop.
In the next TechTip, I’ll dig into some further information about the potential to flat tow an EV. There are some EV makers which are evaluating the possibility of flat towing and while it is a fast-changing area there are some possibilities that may arise going forward.