jhorsf Posted April 5, 2012 Share Posted April 5, 2012 Derek Uzzell - 2012-04-05 11:20 AM OK, imagine that I’ve added a tow-bar to my motorhome and had a little car converted so that it can be towed via an inertia-braked A-frame system provided by a specialist UK manufacturer. To side-step potential arguments about Type Approval and the like, I’ve chosen a lightweight kit-car from the 1960s that pre-dates Type Approval. This (notional) car has big non-power-assisted brakes that are unquestionably capable of providing the braking performance stipulated by UK trailer regulations if the car’s brake-pedal is pulled on by an inertia-braking system's operating cable. I’ve had the car suitably wired up electrically and I’ve attached to the car a registration-plate that carries my motorhome’s registration-number. So is this motorhome + car combination legal in the UK? Well, I would suggest not simply because of the braking-while-reversing issue. This is touched on in the much-quoted Department for Transport advice document, saying “From 1 October 1988 the inertia braking system was required to allow the trailer to be reversed by the towing vehicle without imposing a sustained drag and such devices used for this purpose must engage and disengage automatically. This will be very difficult to achieve on an “A” frame using an inertia (overrun) device.” It’s always been glaringly plain to me that the design of an A-frame using the inertia-braking principle (which is what most UK motorcaravanners have) is highly unlikely to allow that basic reversing requirement to be satisfactorily met. I discussed this once with a UK A-frame manufacturer who told me he’d asked the DofT to define what “sustained drag” meant and exactly what minimum distance in reverse the vehicle combination needed to cover to comply with UK trailer rules. He said that no definitive answer had been received from the DofT. I replied that these were pointless questions, as we both knew there were easily-envisaged situations where it would be impossible to reverse a car on an inertia-braked A-frame unless the braking link between the towing and towed vehicles were first disabled. He agreed this was true, but claimed that the UK regulatory authorities like the police and DofT had far more important things to concern themselves with than microscopically exploring the minutiae of UK trailer regulations. It has been regularly claimed on motorhome forums that it is possible, by very carefully adjusting the inertia-braking system of a traditional A-frame, to obtain satisfactory braking performance when the car is being towed forwards coupled to a reversing capability that is adequate for most driving scenarios. However, a caravan or braked-trailer can theoretically be reversed up any incline to be encountered on UK roads for any distance one cares to specify, but a car on an inertia-braked trailer cannot. I’d argue that, if an A-frame-towed car is agreed to be a “trailer” as far as UK regulations are concerned, then the car must display ALL the braking and reversibility capabilities of an ordinary trailer not just some of them. Cars on inertia-braked A-frames fail to do this. It’s no good seeking to cherry-pick those UK trailer regulations that A-frame systems comply with and conveniently ignore the show-stopping ones. I believe that, if the practice of towing a car on a common-or-garden inertia-braked A-frame were ‘tested’ in a UK court, the practice would not receive legal approval. I’m more confident that UK-marketed A-frame systems that don’t employ inertia-braking could gain legal approval, but not many people use those (yet). As it’s straightforward enough for UK motorcaravanners to obtain insurance for their motorhome + car combination; as (to the best of my knowledge) nobody has been prosecuted for A-frame towing in the UK; as nobody claims that the practice is inherently dangerous, and as UK regulatory authorities do indeed have far more important things to concern themselves with than UK motorhome A-framing small-print, it doesn’t really matter whether UK motorhome A-framing is ‘legal’ here or not. Obviously, if the plan is to try to use UK ‘legality’ to override other EU states’ national laws that forbid motorhome A-framing, that’s something else. Answer http://www.smart-tow.com/ Link to comment Share on other sites More sharing options...
Brambles Posted April 5, 2012 Share Posted April 5, 2012 jhorsf - 2012-04-05 3:23 PM .................Answer http://www.smart-tow.com/ Wow!!! Just look at this front wheels castor the wrong way on reverse and scrape over the ground. If Smart Tow produced that video they are pretty stupid to publish it. Clearly that is not good for the tyres or the ball joints/suspension arms etc. So based on this video, I would say reversing is not possible. The speed at which the front steering corrects to a straight ahead again could easly damage the steering rack or at least blow of one of the bellows. Link to comment Share on other sites More sharing options...
lennyhb Posted April 5, 2012 Share Posted April 5, 2012 Wow just listen to the horrible noise looks like the best place for that Smart is the scrapie after making that video. Link to comment Share on other sites More sharing options...
Dr Dave Posted April 5, 2012 Share Posted April 5, 2012 It would probably cause less damage if you put the smart on its roof and scraped it around the corner. Flat spot on the tyres or what? Come to think of it a roof rack with wheels on would that be legal? Link to comment Share on other sites More sharing options...
Guest peter Posted April 5, 2012 Share Posted April 5, 2012 Derek Uzzell - 2012-04-05 11:20 AM OK, imagine that I’ve added a tow-bar to my motorhome and had a little car converted so that it can be towed via an inertia-braked A-frame system provided by a specialist UK manufacturer. To side-step potential arguments about Type Approval and the like, I’ve chosen a lightweight kit-car from the 1960s that pre-dates Type Approval. This (notional) car has big non-power-assisted brakes that are unquestionably capable of providing the braking performance stipulated by UK trailer regulations if the car’s brake-pedal is pulled on by an inertia-braking system's operating cable. I’ve had the car suitably wired up electrically and I’ve attached to the car a registration-plate that carries my motorhome’s registration-number. So is this motorhome + car combination legal in the UK? Well, I would suggest not simply because of the braking-while-reversing issue. This is touched on in the much-quoted Department for Transport advice document, saying “From 1 October 1988 the inertia braking system was required to allow the trailer to be reversed by the towing vehicle without imposing a sustained drag and such devices used for this purpose must engage and disengage automatically. This will be very difficult to achieve on an “A” frame using an inertia (overrun) device.” It’s always been glaringly plain to me that the design of an A-frame using the inertia-braking principle (which is what most UK motorcaravanners have) is highly unlikely to allow that basic reversing requirement to be satisfactorily met. I discussed this once with a UK A-frame manufacturer who told me he’d asked the DofT to define what “sustained drag” meant and exactly what minimum distance in reverse the vehicle combination needed to cover to comply with UK trailer rules. He said that no definitive answer had been received from the DofT. I replied that these were pointless questions, as we both knew there were easily-envisaged situations where it would be impossible to reverse a car on an inertia-braked A-frame unless the braking link between the towing and towed vehicles were first disabled. He agreed this was true, but claimed that the UK regulatory authorities like the police and DofT had far more important things to concern themselves with than microscopically exploring the minutiae of UK trailer regulations. It has been regularly claimed on motorhome forums that it is possible, by very carefully adjusting the inertia-braking system of a traditional A-frame, to obtain satisfactory braking performance when the car is being towed forwards coupled to a reversing capability that is adequate for most driving scenarios. However, a caravan or braked-trailer can theoretically be reversed up any incline to be encountered on UK roads for any distance one cares to specify, but a car on an inertia-braked trailer cannot. I’d argue that, if an A-frame-towed car is agreed to be a “trailer” as far as UK regulations are concerned, then the car must display ALL the braking and reversibility capabilities of an ordinary trailer not just some of them. Cars on inertia-braked A-frames fail to do this. It’s no good seeking to cherry-pick those UK trailer regulations that A-frame systems comply with and conveniently ignore the show-stopping ones. I believe that, if the practice of towing a car on a common-or-garden inertia-braked A-frame were ‘tested’ in a UK court, the practice would not receive legal approval. I’m more confident that UK-marketed A-frame systems that don’t employ inertia-braking could gain legal approval, but not many people use those (yet). As it’s straightforward enough for UK motorcaravanners to obtain insurance for their motorhome + car combination; as (to the best of my knowledge) nobody has been prosecuted for A-frame towing in the UK; as nobody claims that the practice is inherently dangerous, and as UK regulatory authorities do indeed have far more important things to concern themselves with than UK motorhome A-framing small-print, it doesn’t really matter whether UK motorhome A-framing is ‘legal’ here or not. Obviously, if the plan is to try to use UK ‘legality’ to override other EU states’ national laws that forbid motorhome A-framing, that’s something else.The reversing connundrum with a frames can be overcome. The solution is blatantly obvious to anyone with a background in engineering. All you need to do is fit a 12volt solenoid that operates a pin that locks the piston of the overun braking system. This solenoid can easilly be operated automatically by linking the power wire to the reversing light circuit of the plug. Thus when reverse gear is selected the pin locks the overun piston and you can reverse if you want to. Link to comment Share on other sites More sharing options...
Brambles Posted April 6, 2012 Share Posted April 6, 2012 ...... just leaving the streering castor problem to be resolved when reversing! Link to comment Share on other sites More sharing options...
Derek Uzzell Posted April 6, 2012 Share Posted April 6, 2012 peter - 2012-04-05 10:17 PM The reversing connundrum with a frames can be overcome. The solution is blatantly obvious to anyone with a background in engineering. All you need to do is fit a 12volt solenoid that operates a pin that locks the piston of the overun braking system. This solenoid can easilly be operated automatically by linking the power wire to the reversing light circuit of the plug. Thus when reverse gear is selected the pin locks the overun piston and you can reverse if you want to. Of course there are simple engineering solutions to prevent the brakes being operated on a car being reversed while on an inertia-braked A-frame, but I'm not aware that any UK manufacturer of inertia-braked A-frames offers such a solution as standard or as an option. It will be interesting to see what the Rt.Hon. Nick Herbert MP, Minister of State for Policing and Criminal Justice does with Half Moon Bay (Leisure) Ltd's "White Paper - Summary of A-Frames in UK Market". Whatever the result, it's nice to see that at least one UK A-frame supplier is making an effort to clarify matters. Link to comment Share on other sites More sharing options...
Dr Dave Posted April 6, 2012 Share Posted April 6, 2012 Peter I don't agree that your simplistic solution would work in every eventuality, imagine you had braked the motorhome and this had compressed the overrun coupling. you would have to move forward to un-compress the coupling before reversing and enable the solenoid pin to lock and this is not always going to be possible and i it wont work every time its a non starter. Link to comment Share on other sites More sharing options...
Mel B Posted April 7, 2012 Share Posted April 7, 2012 With all this talk about reversing the A-framed vehicle, one thing that has also to be considered is the ability of the driver to do it!!! From the number of people we've 'met who can't reverse a car on its own down a road, never mind with a trailer it is frightening that they are legally allowed on the road. Add a motorhome and an A-framed car or a small trailer the difficulty is increased as small 'units' are more difficult to reverse than a large unit as its not easy to see what the trailer/car is doing (even with a camera). Now include the resistance of the A-framed car and the 'damage' that is caused to it such as scrubbed wheels, side pressure on bearings etc (as has been mentioned) somehow I don't think reversing vehilcls on A-frames them is a sensible thing to do at all!!! 8-) We used to try to do it with our Bond Minicar on a custom made 'bar' and it was night on impossible for more than a foot!!! Link to comment Share on other sites More sharing options...
Guest peter Posted April 9, 2012 Share Posted April 9, 2012 Dr Dave - 2012-04-06 4:59 PMPeterI don't agree that your simplistic solution would work in every eventuality, imagine you had braked the motorhome and this had compressed the overrun coupling. you would have to move forward to un-compress the coupling before reversing and enable the solenoid pin to lock and this is not always going to be possible and i it wont work every time its a non starter.O/K Dr Dave, I'll defer to your superior knowledge of such matters, and I apologise for having the temerity to make a suggestion that might actually be made to work.My god where would we be if every invention that was ever dreamt up had such negative detractors like you to contend with. We would all still be living in caves wrapped up in goatskins. Of course there would be obstacles to overcome on the way to a working unit, that's what the human brain is good at isn't it. You don't think that the first attempt at making anything was a success do you?. What this country needs is innovation and imagination at solving problems. Not herberts popping up and sayig "it'll never work mate, so don't bother trying" Link to comment Share on other sites More sharing options...
Brian Kirby Posted April 10, 2012 Share Posted April 10, 2012 BGD - 2012-04-04 8:01 PM Is A-Framing in the UK legal or illegal? Discuss................. Yes, definitely! :-) Link to comment Share on other sites More sharing options...
Derek Uzzell Posted April 10, 2012 Share Posted April 10, 2012 A Department for Transport spokesman has opined that the concept of a motorhome towing a car on an A-frame in the UK is unlikely to be considered illegal provided that all the relevant trailer regulations are met. As A-frame towing systems vary, it then needs to be asked which, if any, of the systems fully comply with the trailer regulations. This will involve studying the regulations and the A-frame systems very carefully. The 'letter of the law' (not the spirit) would need to be observed and, at the end of the day, it should be possible to decide which systems do fully comply with the regulations and which do not. I would suggest that those systems that do comply can be termed 'UK legal' and those do not can be termed 'UK illegal'. And that's probably as good a definition as it's practicable to get. Link to comment Share on other sites More sharing options...
DJP Posted April 11, 2012 Share Posted April 11, 2012 I have a cunning plan! Make all A Frames Illegal to use anywhere in the world, then re-brand them as V Frames. A frames illegal. No more debates! V frames.........................................., Well it would end the A frame debates and open up a whole new world. >:-) Link to comment Share on other sites More sharing options...
Merle Posted April 11, 2012 Share Posted April 11, 2012 I have a cunning plan! Make all A Frames Illegal to use anywhere in the world, then re-brand them as V Frames. A frames illegal. No more debates! V frames.........................................., Well it would end the A frame debates and open up a whole new world. Is that the two fingured 'V' ? Link to comment Share on other sites More sharing options...
Dr Dave Posted April 11, 2012 Share Posted April 11, 2012 peter - 2012-04-09 6:06 PMDr Dave - 2012-04-06 4:59 PMPeter I don't agree that your simplistic solution would work in every eventuality, imagine you had braked the motorhome and this had compressed the overrun coupling. you would have to move forward to un-compress the coupling before reversing and enable the solenoid pin to lock and this is not always going to be possible and i it wont work every time its a non starter.O/K Dr Dave, I'll defer to your superior knowledge of such matters, and I apologise for having the temerity to make a suggestion that might actually be made to work.My god where would we be if every invention that was ever dreamt up had such negative detractors like you to contend with. We would all still be living in caves wrapped up in goatskins. Of course there would be obstacles to overcome on the way to a working unit, that's what the human brain is good at isn't it. You don't think that the first attempt at making anything was a success do you?. What this country needs is innovation and imagination at solving problems. Not herberts popping up and sayig "it'll never work mate, so don't bother trying"Well well I assume by the sarcasm in your reply and by calling me a herbert that you did not want anyone contributing to or commenting on your simplistic design. Peter please note i did not state that such a system could not be made to work with the addition of some additional components possibly an electrical or hydraulic de-compression valve connected to the hydraulic overrun piston to relieve the action of the compressed coupling during braking and subsequent immediate reversing. I thought that the forum was for debate discussion and opinions. If i stated anything wrong in the reply then i will stand corrected. however you did state...The reversing connundrum with a frames can be overcome. The solution is blatantly obvious to anyone with a background in engineering. All you need to do is fit a 12volt solenoid that operates a pin that locks the piston of the overun braking system. This solenoid can easilly be operated automatically by linking the power wire to the reversing light circuit of the plug. Thus when reverse gear is selected the pin locks the overun piston and you can reverse if you want to.It is not as simple as you stated that's what i commented on and if that makes me a herbert a herbert i must be. Link to comment Share on other sites More sharing options...
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