Unique Dual Sensing setup brakes only when braking is required (both stop light actuation AND the G force (motion sensor) are required to actuate braking. 

Inferior system that works ONLY on a brake light signal from the Motorhome will function on the slightest touch of the  Motorhome brakes and will activate 100% of the towed vehicle brakes. There is no proportionality, the towed vehicle brakes are either ON or OFF. Very binary I/O and cannot react for every given situation.

Inferior systems working ONLY on a signal from the G Sensor then you will at least get 20% braking with 20% braking and 80% braking with 80% braking etc. But if you are going down a long hill or mountain pass under Engine Braking then the “trailer” will sense this and apply its brakes. Soon the towed vehicle’s brakes will overheat and you could arrive at the  bottom of the hill with smoking, burnt out brakes!

Only with Dual Sensing do you solve the problem. Under engine braking, although the G Sensor is sensing deceleration, the brakes will not be applied until you touch the brakes in the motorhome and provide the second signal to the system.

Under light braking on the flat a 12v signal may be sent to the brake system but with little or no deceleration sensed the G Sensor will keep any braking safely proportional.

  • Because our unique system features dual sensing – it offers proportionate braking effort. (Proportionate means it brakes as you do – gentle or hard it mirrors your braking effort
  • Pneumatic brake actuation means fast responsive braking response ( 1 second delay in braking at 60 mph = 88ft further travelled)
  • DOT approved high pressure pipe AND large diameter 3/8 id Vacuum
    pipe (same as most vehicles) (Inferior systems with smaller ID pipe (1/8) reduces the volume of vacuum available for braking and the rate it can be replenished under load is diminished)
  • Visible monitor in car optional
  • Tow A Frame braking system tested on MOT brake test rollers passed the MOT brake efficiency test using only the TowAFrame emergency braking system
  • TowAFrame offer 24 month UK warranty as standard
  • The SmartboxDUO system has had many accolades from Motorhome Readers’ choice Awards and substantiates our confidence in this product.
  • 2014, 2015, 2016 Gold Award 
  • 2017 Silver Award

Our A frames, tow pins, threaded inserts, crash bar modifications fabrication and installations are all carried out in the UK – we value our suppliers as well as our customers. 

Tow TOUGH tested to destruction at 5000kg, Tow GLIDE tested to Tow ball failure – testing halted at 7100kg Pull test

Calculating Towing rolling resistance, the formula for calculating pulling effort on the flat, on tarmac surface for a rolling vehicle is 1000kg car divided by 25, this formula gives = 40kg rolling resistance, this varies with gradient and how hard you accelerate, in addition surface type can make a big difference, Grass can be 1000kg / 4 = 250kg resistance. This product is designed solely for use on tarmac surfaces.

  1. The Brake light signal AND deceleration force activate the [Smartbox-DUO] pump.
  2. Pump creates vacuum for servo and activates the pneumatic brake actuator on the pedal with corresponding braking effort.
  3. The brake actuator depresses the brake pedal with proportionate force until braking is no longer required.
  4. System is ready for action when required offering intelligent braking.