Recommended Flat Towing Setup for a 2018 Ford F-150 w/ a Motorhome that has Air Brakes

Updated 07/25/2025 | Published 07/24/2025

Products Featured in This Question

Demco Stay-IN-Play Duo Flat Tow Brake System for RVs w/ Hydraulic Brakes - Proportional

(799)

$1245.50

etrailer XHD Non-Binding Tow Bar for Roadmaster Direct-Connect Base Plate - RV Mount - 10,500 lbs

(209)

$1018.64

Roadmaster 4-Diode Universal Wiring Kit for Towed Vehicles - 7-Way to 6-Way Coiled Adapter Cord

(3386)

$167.90

Roadmaster Battery Charge Line Kit for Towed Vehicles

(1324)

$43.45

Roadmaster Direct-Connect Base Plate Kit - Removable Arms

(3493)

$575.00

Roadmaster Brake-Lite Relay Kit for Towed Vehicles

(732)

$48.06

Demco Air Force One Flat Tow Brake System for RVs w/ Air Brakes - Proportional

(539)

$1399.00

Question:

The SMI duo brake system says it's for RVs with hydraulic brakes. What about for RVs with Air Brakes (2019 Tiffin AB40ip) when towing a 2018 F-150 Lariat?

asked by: Mike H

Expert Reply:

Hey Mike, welcome back. For RV's with air brakes, you'll want the Demco Air Force One Flat Tow Brake System for RVs w/ Air Brakes - item # SM99243. This system uses the air pressure from your Tiffin's brake line to apply your F-150's brakes at the same time, with the same intensity.

Here are the rest of the parts you'll need to flat tow your 2018 Ford F-150 Lariat:

Tow Bar and Safety Chains - etrailer XHD Non-Binding Tow Bar for Roadmaster Direct-Connect Base Plate item # e84ZR

Base Plate Kit - Roadmaster Direct-Connect Base Plate Kit - Removable Arms item # RM-524431-5

Wiring Harness - Roadmaster Diode 7-Wire to 6-Wire Flexo-Coil Wiring Kit item # RM-15267

Charge Line - Roadmaster Battery Charge Line Kit for Towed Vehicles item # RM-156-25

Brake Light Switch - Roadmaster Brake-Lite Relay Kit for Towed Vehicles item # RM-88400

High Low Adapter - The tow bar needs to be within 3" of level. If you measure the height of the inside top of the hitch receiver tube on your RV, and the height difference is more than 3 inches above/below the base plate tab height, you'll need a high/low adapter. I have linked a FAQ article that explains all this in more detail along with our selection of adapters.

Have you ever flat towed before and does your Tiffin have a hitch?

expert reply by: Jerred H

Mike H.

7/24/2025

Thanks! I have not flat towed before, although I have lots of towing experience with a variety of trailers up to 10,000 lbs. Out Tiffin has a hitch, 7 wire plug, and an airline with a quick-disconnect fitting already there at the hitch. Also has a prodigy brake controller so I assume the PO towed something back there.

Jerred H.

7/25/2025

@MikeH You're welcome and thanks for all of that information! That quick connect is going to be a big help! You most likely have the air tank or a comparable connection to your braking system. That means all you need is the Demco Air Force One Flat Tow Brake System for 2020 and Newer Tiffin Chassis RVs w/Factory Air Brakes item # DM55MV. This is the same towed vehicle set up for your F-150 but all you'll have to do is plug into that quick connect on the back of your motorhome. You won't have to cut into air lines to install the tank that comes with item # SM99243.