FAQ: Can I tow a car on an A Frame behind my Motorhome?
Discussion
This question is often asked, and this FAQ thread is an experiment in trying to create a useful set of answers.
Dept for Transport Official Guidance
Dept for Transport Official Guidance
Dept for Transport said:
May 2010
Information Sheet “A”-Frames and Dollies
“A”- Frames
When an "A" frame is attached to a vehicle (e.g. a motor car) and towed by a motor vehicle (e.g. motorhome) we believe the "A" frame and car become a single unit and as such are classified in legislation as a trailer. As a consequence the car and “A”-frame are required to meet the technical requirements for trailers when used on the road in Great Britain. These requirements are contained within the Road Vehicles (Construction and Use) Regulations 1986 (SI 1986/1078) as amended (C&U) and the Road Vehicles Lighting Regulations 1989 (SI 1989/1796) as amended (RVLR).
Trailers having a combined axle mass not exceeding 750kg are not required to have brakes fitted. However, if the trailer (regardless of mass) is fitted with a braking system, then all brakes in that system must operate correctly. The regulations do not include design constraints on how this should be achieved but, for example, it could be met by direct linking of the trailer brakes to the brake system of the towing vehicle or by automatic inertia (overrun) operation via the towing hitch. Inertia systems can only be used for trailers with a maximum combined axle mass of 3500kg.
Regulations 15 and 16 of C&U set out the braking requirements - including minimum braking efficiencies for trailer brakes. Subject to certain age exemptions, the regulation requires the braking system to comply with the construction, fitting and performance requirements of European Community Directive 71/320/EEC along with its various amending Directives. Alternatively the braking system can comply with the corresponding UNECE Regulation No.13.09.
In addition, C&U Regulation 18 requires the braking system to be maintained in good and efficient working order. If the brakes of the towing vehicle do not directly operate the trailer brakes the use of an inertia (overrun) system is acceptable. If the trailer braking system has power assistance (i.e. servo or full power) it is likely that this assistance will be required while in motion to meet the required braking efficiencies. This is because once the vacuum reservoir is depleted it is possible that the brakes will not meet the braking efficiency. To prevent the trailer being used illegally a remote vacuum pump, powered from the tow vehicle, could be installed to recharge the reservoir, alternatively a source could be made available from the tow vehicle. 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.
Other provisions from Regulation 15 and Regulation 86A of C&U require the fitting and use of a secondary coupling system in which the trailer is stopped automatically if the main coupling separates whilst the combination is in motion. Alternatively, in the case of trailers up to a maximum mass of 1500kg, the drawbar must be prevented from touching the ground and the trailer able to retain some residual steering.
Whilst being towed, trailers are subject to the relevant requirements given in RVLR, including the use of triangular red reflectors. There would be further requirements for the display of the appropriate number plate, etc.
From the above I hope it is clear that we believe the use of "A" frames to tow cars behind other vehicles is legal provided the braking and lighting requirements are met. However, while this is our understanding of the Regulations, it is only the Courts which can reach a definitive interpretation of the law.
Dollies
The use of “dollies” is intended for the recovery of broken down vehicles, not for the transportation of a vehicle from “A” to “B”.
Under Regulation 83 of C&U a motor car is permitted to tow two trailers when one of them is a towing implement and the other is secured to and either rests on or is suspended from the implement. When used for recovering broken down vehicles “dollies” are exempt from having an operational braking system fitted, provided that the towing vehicle is capable of meeting the minimum prescribed braking requirements for the combination. However, if “dollies” are used for the transportation of perfectly functioning vehicles they will need to fitted with an operational braking system. Additionally the brakes on the wheels of the towed car which are in contact with the road must work and meet the specified 50% braking efficiency required for a trailer. The dolly would also be required by Regulation 22 of C&U to be fitted with suspension. Regulations 19 and 22 in C&U permit a broken down vehicle to be recovered without complying with these requirements. However, there is further legislation under the Road Traffic Regulation Act 1984 that introduces a limitation on the maximum speed that the combination can be driven; this is 40mph on motorways and 20mph on other roads.
Legislation
The Department for Transport does not supply copies of legislation but some information on various sources where they can be obtained is provided below. If you would like to purchase printed copies of Statutory Instruments these are available from The Stationery Office (TSO):
TSO Orders/Post Cash Department
PO Box 29
Norwich
NR3 1GN
Tel: 0870 600 5522
Fax: 0870 600 5533
Email: customer.services@tso.co.uk
Website: www.tsoshop.co.uk
European Braking Directive:
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?...
UN-ECE Regulation 13 and amendments:
http://www.unece.org/trans/main/wp29/wp29regs1-20....
Further information
If you require any further information regarding the content of this information sheet, please contact the DfT at the address below:
Transport Technology and Standards
Department for Transport
Zone 2/05
Great Minster House Telephone: 020 7944 2091
76 Marsham Street Fax: 020 7944 2196
London Email: TTS.enquiries@dft.gsi.gov.uk
SW1P 4DR
NOTE: The information in this document is a summary of the Department’s understanding of what the law requires. However, ultimately the interpretation of the law is a matter for the courts based on individual facts of any particular case. You are therefore advised to consult the relevant legislation and, if necessary, seek independent advice.
May 2010
Information Sheet “A”-Frames and Dollies
“A”- Frames
When an "A" frame is attached to a vehicle (e.g. a motor car) and towed by a motor vehicle (e.g. motorhome) we believe the "A" frame and car become a single unit and as such are classified in legislation as a trailer. As a consequence the car and “A”-frame are required to meet the technical requirements for trailers when used on the road in Great Britain. These requirements are contained within the Road Vehicles (Construction and Use) Regulations 1986 (SI 1986/1078) as amended (C&U) and the Road Vehicles Lighting Regulations 1989 (SI 1989/1796) as amended (RVLR).
Trailers having a combined axle mass not exceeding 750kg are not required to have brakes fitted. However, if the trailer (regardless of mass) is fitted with a braking system, then all brakes in that system must operate correctly. The regulations do not include design constraints on how this should be achieved but, for example, it could be met by direct linking of the trailer brakes to the brake system of the towing vehicle or by automatic inertia (overrun) operation via the towing hitch. Inertia systems can only be used for trailers with a maximum combined axle mass of 3500kg.
Regulations 15 and 16 of C&U set out the braking requirements - including minimum braking efficiencies for trailer brakes. Subject to certain age exemptions, the regulation requires the braking system to comply with the construction, fitting and performance requirements of European Community Directive 71/320/EEC along with its various amending Directives. Alternatively the braking system can comply with the corresponding UNECE Regulation No.13.09.
In addition, C&U Regulation 18 requires the braking system to be maintained in good and efficient working order. If the brakes of the towing vehicle do not directly operate the trailer brakes the use of an inertia (overrun) system is acceptable. If the trailer braking system has power assistance (i.e. servo or full power) it is likely that this assistance will be required while in motion to meet the required braking efficiencies. This is because once the vacuum reservoir is depleted it is possible that the brakes will not meet the braking efficiency. To prevent the trailer being used illegally a remote vacuum pump, powered from the tow vehicle, could be installed to recharge the reservoir, alternatively a source could be made available from the tow vehicle. 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.
Other provisions from Regulation 15 and Regulation 86A of C&U require the fitting and use of a secondary coupling system in which the trailer is stopped automatically if the main coupling separates whilst the combination is in motion. Alternatively, in the case of trailers up to a maximum mass of 1500kg, the drawbar must be prevented from touching the ground and the trailer able to retain some residual steering.
Whilst being towed, trailers are subject to the relevant requirements given in RVLR, including the use of triangular red reflectors. There would be further requirements for the display of the appropriate number plate, etc.
From the above I hope it is clear that we believe the use of "A" frames to tow cars behind other vehicles is legal provided the braking and lighting requirements are met. However, while this is our understanding of the Regulations, it is only the Courts which can reach a definitive interpretation of the law.
Dollies
The use of “dollies” is intended for the recovery of broken down vehicles, not for the transportation of a vehicle from “A” to “B”.
Under Regulation 83 of C&U a motor car is permitted to tow two trailers when one of them is a towing implement and the other is secured to and either rests on or is suspended from the implement. When used for recovering broken down vehicles “dollies” are exempt from having an operational braking system fitted, provided that the towing vehicle is capable of meeting the minimum prescribed braking requirements for the combination. However, if “dollies” are used for the transportation of perfectly functioning vehicles they will need to fitted with an operational braking system. Additionally the brakes on the wheels of the towed car which are in contact with the road must work and meet the specified 50% braking efficiency required for a trailer. The dolly would also be required by Regulation 22 of C&U to be fitted with suspension. Regulations 19 and 22 in C&U permit a broken down vehicle to be recovered without complying with these requirements. However, there is further legislation under the Road Traffic Regulation Act 1984 that introduces a limitation on the maximum speed that the combination can be driven; this is 40mph on motorways and 20mph on other roads.
Legislation
The Department for Transport does not supply copies of legislation but some information on various sources where they can be obtained is provided below. If you would like to purchase printed copies of Statutory Instruments these are available from The Stationery Office (TSO):
TSO Orders/Post Cash Department
PO Box 29
Norwich
NR3 1GN
Tel: 0870 600 5522
Fax: 0870 600 5533
Email: customer.services@tso.co.uk
Website: www.tsoshop.co.uk
European Braking Directive:
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?...
UN-ECE Regulation 13 and amendments:
http://www.unece.org/trans/main/wp29/wp29regs1-20....
Further information
If you require any further information regarding the content of this information sheet, please contact the DfT at the address below:
Transport Technology and Standards
Department for Transport
Zone 2/05
Great Minster House Telephone: 020 7944 2091
76 Marsham Street Fax: 020 7944 2196
London Email: TTS.enquiries@dft.gsi.gov.uk
SW1P 4DR
NOTE: The information in this document is a summary of the Department’s understanding of what the law requires. However, ultimately the interpretation of the law is a matter for the courts based on individual facts of any particular case. You are therefore advised to consult the relevant legislation and, if necessary, seek independent advice.
May 2010
When you hitch a caravan up to a car, when the car brakes, the caravan tries to run into the back of the car, the plunger on the caravans towing A frame gets pushed in, and applies the brakes to the caravan. The A frame attached to the car does the same thing, a cable is attached to the cars brakes.
We used to tow a Panda behind a Kontiki, the keys are left in the ignition to keep the steering lock off, so the car just follows, and when it tries to run into the tow vehicle, the brakes are applied.
http://www.caratow.com/home.php
We used to tow a Panda behind a Kontiki, the keys are left in the ignition to keep the steering lock off, so the car just follows, and when it tries to run into the tow vehicle, the brakes are applied.
http://www.caratow.com/home.php
Balmoral Green said:
When you hitch a caravan up to a car, when the car brakes, the caravan tries to run into the back of the car, the plunger on the caravans towing A frame gets pushed in, and applies the brakes to the caravan. The A frame attached to the car does the same thing, a cable is attached to the cars brakes.
I know that 
But reading the opening regs that isnt allowed unless the trailer is over 3500kg or it doesnt have a full braking system
A car isn't and does.
i.e. somehow the tow vehicle has to have full control of the trailer braking system - see the bit about servos too.
When I towed broken down vehicles with my A bar (A frame by the description given here) there was a cable device that was fitted to the broken down car's brake pedal and braced against the front of its seat (yes we had to keep every thing clean in storage). This thick cable then needed to be run through an open (ish) window and was attached to the front of the A bar bracket which had a [bloodyawfuldescription] pantograph style arrangement[/bloodyawfuldescription] on a sliding fitting on the tow bar end of it. There is an adjustment doodah invloved too, so it rings all bells, fits all sizes. Brake and the pedal is pushed down. Frankly the brakes would work even if the servo/engine is off, servos just make the pedal effort less, in general.
It works but is a sod if it's likely to be raining
Because it needs a partially open window
I used to block off as much as possible of the "hole" with a couple of lengths of spongey pipe insulation and sticky tape
(Heath_Robinson need NOT apply)
It works but is a sod if it's likely to be raining
Because it needs a partially open window
I used to block off as much as possible of the "hole" with a couple of lengths of spongey pipe insulation and sticky tape
(Heath_Robinson need NOT apply)
Lollers @ tvrgit post. (edited where has it gone??)
But to paraphrase Magnus Magnusson "I've started so now it seems as if I must finish"
Crikey, to be honest started this subject as thought it would be relatively straight forward given the DfT guidance, but a lack of comprehension plus some poor wording by DfT has led to confusion by some.
God only knows what it would be like with the speed limits, vans and dual carriageways version.
Right to (not) work.
Please note, if I quote somebody it isn't to make a criticism, except perhaps in saaby's case, but to pick up on a point, so please don't take offence, or a gate, as none intended.
DfT do not help themselves by using the term combined axle mass, which I would take to mean the measured axle load. I can see, perhaps, at a push how they could say this, but tbh I think they are wrong, and as DfT say it would be up to a court to decide.
aiui the actual wording in respect of unbraked trailers says "Trailers with a maximum total design axle weight which does not exceed 750 kg. " (Slight paraphrasing for clarity)
If you read the applicable EU directive, and again paraphrasing, it says
Trailers with a maximum weight not exceeding 0 775 metric tons, "Maximum weight" meaning the maximum weight stated by the vehicle manufacturer to be technically permissible.
I don't know which supercedes which I think the UK 750kgs as they refer to the EU directive and then place a slightly different limit, but hell what do I know, up to the courts.
So a Smart car would fall foul of this, in fact there are very few cars that would, even a CAterham wouldn't. Some micro-cars would, eg those Aixam, and the smaller electric ones.
Then we get
DfT hasn't helped with their wording, but inertia is only allowable up to MAM 3500kg, above that you have to have some braking system linked in to towing vehicle or operable by driver aiui. Think trucks, air lines etc.
However the fly in the ointment is that regardless of the weight, MAM of the trailer, brakes if fitted must work with efficiency of 50% and that is where to my mind the A frame system usually falls down.
see next post.
But to paraphrase Magnus Magnusson "I've started so now it seems as if I must finish"
Crikey, to be honest started this subject as thought it would be relatively straight forward given the DfT guidance, but a lack of comprehension plus some poor wording by DfT has led to confusion by some.
God only knows what it would be like with the speed limits, vans and dual carriageways version.
Right to (not) work.
Please note, if I quote somebody it isn't to make a criticism, except perhaps in saaby's case, but to pick up on a point, so please don't take offence, or a gate, as none intended.
john_p said:
A Smart Fortwo unladen weighs 730kg so maybe wouldn't need any brakes
Common mistake, unladen weight is not the issue, it is legally the Maximum Authorised Mass, or max laden weight, or in trailer terms the max plated weight that is the measure.DfT do not help themselves by using the term combined axle mass, which I would take to mean the measured axle load. I can see, perhaps, at a push how they could say this, but tbh I think they are wrong, and as DfT say it would be up to a court to decide.
aiui the actual wording in respect of unbraked trailers says "Trailers with a maximum total design axle weight which does not exceed 750 kg. " (Slight paraphrasing for clarity)
If you read the applicable EU directive, and again paraphrasing, it says
Trailers with a maximum weight not exceeding 0 775 metric tons, "Maximum weight" meaning the maximum weight stated by the vehicle manufacturer to be technically permissible.
I don't know which supercedes which I think the UK 750kgs as they refer to the EU directive and then place a slightly different limit, but hell what do I know, up to the courts.
So a Smart car would fall foul of this, in fact there are very few cars that would, even a CAterham wouldn't. Some micro-cars would, eg those Aixam, and the smaller electric ones.
Then we get
saaby93 said:
An inertia brake option is only acceptable above 3500kg.
No!DfT hasn't helped with their wording, but inertia is only allowable up to MAM 3500kg, above that you have to have some braking system linked in to towing vehicle or operable by driver aiui. Think trucks, air lines etc.
However the fly in the ointment is that regardless of the weight, MAM of the trailer, brakes if fitted must work with efficiency of 50% and that is where to my mind the A frame system usually falls down.
see next post.
Edited by F i F on Friday 21st January 09:49
perdu gives a good description of how these things work, but to my mind , and DfT infers, the issue is that once the brake servo reservoir is exhausted, a bit of bent tin pushing on the now unservoed brake pedal via a wire looped through an open window may or may not provide the required braking efficiency and that is in my opinion a valid point.
Also suggest that a secondary braking system in case of trailer detachment won't be able to stop vehicle with necessary efficiency when servo not working.
Again up to a court and a detailed vehicle examination to decide.
Also suggest that a secondary braking system in case of trailer detachment won't be able to stop vehicle with necessary efficiency when servo not working.
Again up to a court and a detailed vehicle examination to decide.
saaby93 said:
F i F said:
Trailers with a maximum weight not exceeding 0 775 metric tons, "Maximum weight" meaning the maximum weight stated by the vehicle manufacturer to be technically permissible.
I don't know which supercedes which I think the UK 750kgs as they refer to the EU directive and then place a slightly different limit, but hell what do I know, up to the courts.
Tell me if I'm wrong but that weight limit which I assumed the Smart was below, is overuled by the phrase about the braking system, so since a Smart has a braking system, that system has to be operational - hence perdu's Heath Robinson approachI don't know which supercedes which I think the UK 750kgs as they refer to the EU directive and then place a slightly different limit, but hell what do I know, up to the courts.
As I said...
F i F said:
However the fly in the ointment is that regardless of the weight, MAM of the trailer, brakes if fitted must work.....
Plus that bit you've quoted was in the bit where somebody was talking about unladen weight and I was showing unladen weight has nowt to do with it.
Or?
The issue is, that according the link posted by Balmoral Green, such a system meets the DfT interpretation for a vehicle <1500kg MAM, including when the reservoir is exhausted aand the trailer breaks away.
And in theory a vehicle combo legal to be driven in UK can legally be driven all over EU, however try explaining that to a foreign copper who "No comprendo el inglés" when he wants his 60 euro fixed penalty.
Finally I'd bet my Mrs' engagement ring (without her permission of course) that the majority of Smarts etc we see behind motorhomes are not legal.
And I'm not editing this post again, so there.
Edited by F i F on Friday 21st January 12:40
Update to the FAQ.
As outlined above one of the big concerns expressed has been the efficiency of the towed vehicle brakes after the brake servo reservoir has been exhausted, both on overrun braking and in breakaway situation.
The link here http://www.smart-tow.com/braking.htm is for a system which alleges to deal with this issue of the dead pedal and conform to the necessary regulations.
Important Note:- by linking to this manufacturer's commercial website Pistonheads nor the author in no way endorses nor approves or makes judgement regarding the legality and efficacy of the system. That is a matter for the purchaser to decide and the responsibility of the driver.
As outlined above one of the big concerns expressed has been the efficiency of the towed vehicle brakes after the brake servo reservoir has been exhausted, both on overrun braking and in breakaway situation.
The link here http://www.smart-tow.com/braking.htm is for a system which alleges to deal with this issue of the dead pedal and conform to the necessary regulations.
Smart Tow website said:
Vacuum Assisted Braking
Braking the way your vehicle manufacturer intended
One of the key problems with ordinary A-Frames, that use a manual overrun system to apply the towed vehicle's brakes, is that it is invariably operating on a "Dead Pedal" and therefore may not meet the braking efficiencies required by law. If your towed vehicle has power assisted brakes, energised by vacuum from the engine inlet manifold to the master servo, then when the towed vehicle's engine is not running it is not providing vacuum to the brake's servo and is therefore unlikely to meet an effective capacity, according to the Construction and Use Regulations and EC Directive 71/320, without applying excessive brute force to the dead brake pedal.
SmartBox Duo vacuum braking is different
SmartBox DUO vacuum assisted braking provides both vacuum and air pressure. The SmartBox DUO system energizes the towed vehicle's power assisted servo brakes without the engine running, so you have a soft and effective brake pedal. Once engaged, SmartBox DUO replenishes the vacuum in the car's power assisted servo brake system. By replenishing the vacuum, gentle smooth pressure is applied to the towed vehicle's brakes. With the power assisted servo brakes active, only 10 - 12 pounds of pressure is required to apply the brakes effectively and provide a gentle smooth stop in compliance with the requirements of the Construction and Use Regulations for braked trailers.
SmartBox DUO requires two separate signals to activate the towed vehicle brakes. Deceleration from the G sensor plus a signal from the Motorhome brake light switch. Using two activation signals is the best method for eliminating complicated electronics, control unwanted or unnecessary activation of the towed vehicle brakes and allows for an automatic reverse facility as required by law.
We believe Smart-Tow combined with SmartBox DUO vacuum assisted braking fully meets the requirements of the Construction and Use Regulations and European Community Directives 71/320/EEC and 98/12/EC.
Lot more information on the website.Braking the way your vehicle manufacturer intended
One of the key problems with ordinary A-Frames, that use a manual overrun system to apply the towed vehicle's brakes, is that it is invariably operating on a "Dead Pedal" and therefore may not meet the braking efficiencies required by law. If your towed vehicle has power assisted brakes, energised by vacuum from the engine inlet manifold to the master servo, then when the towed vehicle's engine is not running it is not providing vacuum to the brake's servo and is therefore unlikely to meet an effective capacity, according to the Construction and Use Regulations and EC Directive 71/320, without applying excessive brute force to the dead brake pedal.
SmartBox Duo vacuum braking is different
SmartBox DUO vacuum assisted braking provides both vacuum and air pressure. The SmartBox DUO system energizes the towed vehicle's power assisted servo brakes without the engine running, so you have a soft and effective brake pedal. Once engaged, SmartBox DUO replenishes the vacuum in the car's power assisted servo brake system. By replenishing the vacuum, gentle smooth pressure is applied to the towed vehicle's brakes. With the power assisted servo brakes active, only 10 - 12 pounds of pressure is required to apply the brakes effectively and provide a gentle smooth stop in compliance with the requirements of the Construction and Use Regulations for braked trailers.
SmartBox DUO requires two separate signals to activate the towed vehicle brakes. Deceleration from the G sensor plus a signal from the Motorhome brake light switch. Using two activation signals is the best method for eliminating complicated electronics, control unwanted or unnecessary activation of the towed vehicle brakes and allows for an automatic reverse facility as required by law.
We believe Smart-Tow combined with SmartBox DUO vacuum assisted braking fully meets the requirements of the Construction and Use Regulations and European Community Directives 71/320/EEC and 98/12/EC.
Important Note:- by linking to this manufacturer's commercial website Pistonheads nor the author in no way endorses nor approves or makes judgement regarding the legality and efficacy of the system. That is a matter for the purchaser to decide and the responsibility of the driver.
Edited by F i F on Thursday 22 September 09:21
Another A frame which looks quite good, if expensive.
http://www.unibrake.co.uk/
Again has a servo pump which keeps the towed vehicle operating, and allows an adjustment to help get a good balance between vehicle weights, but £1850.
http://www.unibrake.co.uk/
Again has a servo pump which keeps the towed vehicle operating, and allows an adjustment to help get a good balance between vehicle weights, but £1850.
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