A-framing a small car

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  • I know it's normally the preserve of super motorhomes, but I'm considering getting a small car and tugging it around behind Nora on an a-frame....


    Anyone done it??


    The choice of cars is limited by price, and by which ones a-frames are available for... I was originally thinking a Smart, but ones I can afford seem to have problems.. So now the list seems to be Fiat Panda, Kia Piccanto or Toyota Aygo/Citroen C1/Peugeot 107...


    Has anyone run one of these cars?

  • old version?

    Friend had a smart car and pleased with it.

    Nissan micra? What about a road legal quad?

    It's what I can get an a-frame for... and original Fiat 500s are definitely not cheap!!!

    Guy down the road from me has a little fiat 126 he drags about, says he's happy with it.


    Lots of cheap micras about, timing chain, cheap spares..

    Ditto 126s!



    Micras are ok, I like the idea of a 3 cylinder engine though.. hence the baby Toyota on my list.... I had two 3 cylinder bikes, and loved them both....

  • What are the current requirements for a frames, braking etc?


    When i was offroading i towed an sj410 with a homemade a frame which attached to two points welded on the front of the chassis - completely unbraked as it was under 750kg.


    This was a lot of years ago, and I know there was talk of changing the law/rules but i never kept up with it.

  • Post by NomadicRT ().

    This post was deleted by the author themselves ().
  • Current law seems to be thus...


    1: If your trailer is under 750kg, it doesn't need brakes (no change there).

    2: If your trailer has brakes (regardless of weight) they must work as designed.

    3: Your a-framed car is a trailer.

    4: Therefore it's brakes must work as designed (by the car manufacturer). ie proportionately on front and back wheels.

    5: If your car's brakes are servo assisted while driving, they must be servo assisted while towing, or they're not working as designed....

    6: Your trailer's brakes must not engage when going backwards.


    Soooooooooo....


    The best towing kit uses the brake light feed from the towing vehicle, and an accelerometer to determine that you are braking, and mechanically pushes the brake pedal down, to apply the towed car's brakes... In cars with vacuum servo brakes, the kit includes an electric vacuum pump to keep the servo working. The accelerometer thinks going backwards is braking, but the brake lights aren't on, so the brakes aren't applied when you reverse.....


    Needless to say, that little lot doesn't come cheap!! I can do most of it with an Arduino, but the actuator to depress the brake pedal might be an issue....

  • So its no longer a case of just selecting a car under 750kg then...


    Daz (with the 126) doesnt have any of that, hes using a dolly with the front wheels off the ground. My understanding of this is that they are supposed to be for recovery only..


    Would a windscreen wiper motor with an arm attached be strong enough to press the pedal?


    If you are going to be running a vac pump then maybe a standard air cylinder could maybe be utilised, operated via solenoid valve from your arduino, sucking on the rod end rather than blowing air in the back end?

  • If I was going to do this myself, I'd take a vacuum pump from a small diesel, and spin it with an electric motor, to provide vacuum to the car's servo... The actuator to push the pedal down would ideally be a linear actuator, probably only need 10lbs of push to do the job... I'd have to do some research on that bit...


    I've already interfaced an Arduino to an accelerometer, but that was doing shock detection... My code may need to improve to work with sub 1G levels of force!!


    Or I could save shit-loads of time and effort, and just buy the kit, and install it myself...


    The company selling it claims that despite a-frames being illegal in parts of Europe, no-one has ever been prosecuted for using it, because they can prove that their towed car constitutes a trailer, and fulfils all the requirements of a trailer....

  • Would a compressed air fitting mounted on your towbar connected to your vans vac pump, then a coily hose (think truck trailer hoses) plug into it along with the trailer socket be an option?

    Possibly combined with a small gas bottle or similar as a vacuum reservoir.


    Non electronic braking detection could possibly be achieved by using the same system as the standard braking on trailers, but instead of the overrun lever operating the brakes on the trailer it just operates a microswitch. Brake lights on van + microswitch operates = braking required.

  • Nice thinking... I could run vacuum to the back of Nora, but not sure how the vacuum pump on Nora's alternator (yes really!) would cope under braking.. I guess I could add an extra reservoir, but Mr MOT might complain.... Also, a simple switch on the overrun lever wouldn't give proportional braking......

  • If you add the reservoir in the tow car mr mot wouldnt see it.

    Also, as far as the mot is concerned they check braking effort - so long as they pass should be fine. Position the reservoir at the rear of the van they wouldnt even see it.


    Do you need proportional braking? My old trailer the brakes were on and off, juddered a bit as you slowed as they were off on continuously, but maybe a good damper would sort that?


    Thinking about it, it the overrun lever were to operate a linear pot that combined with some electronicary would give you a proportional system.

  • Do you remember those three or four unbodied reliants from the rat and survival 2006 ish, if i had the room id love one of them! I had some pics on my old pc till the hdd died..

    I remember a really old issue of AWOL that had a Reliant trike with a roll cage - well, a sort of pyramid-y structure - over a central bucket seat.. I think it might have had a V8 Rover engine as well... I loved that machine!!!!