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Three separate things have to line up before you can tow: your licence, your car’s weight limits, and a towbar that is type-approved for your exact vehicle variant. Get any one of them wrong and you are either illegal, unsafe, or out of pocket for a towbar that will not fit. This guide covers all three, plus the electrics question that catches out more people than the rest combined.
What your licence lets you tow
The rules changed on 16 December 2021, and a great deal of what is still published online describes the old position. If you have read that a category B licence limits you to a 3,500kg combined weight, that is out of date.
| When you passed your car test | What you can tow now |
|---|---|
| On or after 1 January 1997 | A trailer up to 3,500kg MAM — this is the entitlement previously known as category BE |
| Before 1 January 1997 | A car and trailer combination up to 8,250kg MAM |
The change removed the need to take a separate B+E trailer test. If your physical licence does not yet show category BE, DVLA adds it the next time you renew — you do not need to do anything to gain the entitlement.
One thing to watch: official documentation still sets out what category B itself covers, which is a vehicle up to 3,500kg plus a trailer up to 750kg, or a combination up to 3,500kg. That is the definition of the licence category, not a description of what you may tow today. The BE entitlement is now granted administratively on top of it.
The licence change removed the test requirement. It did not make you competent — towing a heavy trailer for the first time is a genuinely different driving experience, and voluntary training is worth considering.
The five weights that matter
This is where most people come unstuck, because the terms are used loosely and the numbers live in three different places.
| Term | What it means | Where to find it |
|---|---|---|
| MAM (maximum authorised mass) | The weight of a vehicle or trailer including the maximum load it can safely carry on the road. Also called gross vehicle weight or permissible maximum weight. | VIN plate or sticker; handbook |
| Gross train weight (GTW) | The total weight of the towing vehicle plus trailer plus load. Also called gross combination weight. | VIN plate (often the second figure) |
| Kerbweight | The car’s weight in running order, including fluids and driver. | Handbook. The V5C records “mass in running order” |
| MTPLM | A caravan’s maximum laden weight. | The caravan’s own weight plate, usually near the entrance door |
| Noseweight | The downward load the trailer or caravan puts on the towball. Typically 50–100kg. | Must be measured. Limited by both the car and the towbar |
Reading your VIN plate
The plate is usually under the bonnet or on the driver’s door pillar. It typically lists four figures in order: the vehicle’s maximum weight, the gross train weight, then the maximum permitted weight on the front axle and the rear axle. Subtract the vehicle maximum from the gross train weight and you have the maximum the car is permitted to tow.
Cross-check that against the handbook, because manufacturers often quote separate braked and unbraked trailer limits, and those are the figures you actually work to.
Noseweight — the one nobody mentions
Noseweight is the vertical load pressing down on the towball, and it is limited by two things independently: the car’s maximum permitted noseweight, and the towbar’s own S value. You must respect the lower of the two. Too little noseweight and the trailer is prone to snaking; too much and you overload the rear axle.
You cannot judge it by feel — it needs measuring with a noseweight gauge, with the trailer level and the load in its towing position.
You will also see an “85% guideline” quoted, which suggests keeping the loaded caravan below 85% of the car’s kerbweight. That is a club recommendation for stability, not a legal limit. It is sound advice, particularly for a first-time tower, but it is not the law and it is not what your insurer or the police will measure you against.
Towbar type approval
A towbar is not a generic bracket. Since 1 August 1998, towbars fitted to cars covered by European whole vehicle type approval must themselves be type-approved — originally under EC Directive 94/20/EC, since replaced by UN Regulation 55. The requirement was extended to light commercial vehicles on 29 October 2012.
In practice this means the towbar must carry a label, and that label must show:
- An approval number
- Details of the vehicles it is approved for
- The manufacturer’s trade name or mark
- The class of coupling and its characteristic values
Those markings must be permanent and legible once the device is installed on the vehicle.
D value and S value
Two numbers on the approval plate do the real work. The D value is a characteristic performance figure for the horizontal forces the coupling can handle. The S value is the vertically imposed mass in kilograms — in other words, the towbar’s own noseweight limit.
The label listing the vehicles it is approved for is the proof of fitment — not a make-and-model match on a retailer’s website. If your exact variant is not on that label, the towbar is not approved for your car.
The four towbar types
| Type | How it works | Best for |
|---|---|---|
| Fixed flange | Towball bolted to a flange plate. The bolts allow bumper protectors, stabilisers and drop plates to be fitted. | Caravans, and anyone needing a stabiliser or drop plate |
| Fixed swan neck | A single curved neck with an integral ball. Cleaner, less obtrusive, and less likely to trigger parking sensors. | Bike racks, trailers, general use |
| Detachable | The neck unlocks and comes off completely, leaving the mounting hidden. | Anyone who wants the car to look standard when not towing |
| Retractable | The neck folds or swings away under the bumper, either manually or electrically. | Premium and factory-fit installations |
Note that “flange” and “swan neck” are UK trade terms. Manufacturers use their own classifications — Westfalia, for example, categorises its range as fixed (F10, F20), detachable (A40V, A40H) and retractable (R10).
Why a towbar is always vehicle-specific
There is no such thing as a universal car towbar. Westfalia states it directly: only type-approved towbars that are make and model-specific can be fitted to your vehicle, and a towbar can only be transferred to the exact same make and model — a newer or older model, or a slightly different variation, may not be suitable.
Westfalia lists more than 1,700 different towbar models, and its own product finder requires the manufacturer, the model and the production date before it will return a result. That production date requirement is the clue: mid-generation changes to the rear crash structure, the bumper or the chassis rails can change which bracket fits, without the model name changing at all.
Towing electrics: 7-pin, 12S and 13-pin
This is the part that generates the most confusion and the most wasted money.
| Socket | Standard | What it carries |
|---|---|---|
| 7-pin “12N” (black) | ISO 1724 | The legal road lighting only — indicators, brake lights, rear fog, position/marker/plate lights, common return |
| 7-pin “12S” (white, supplementary) | ISO 3732 | The extras — reverse light, interior lighting, permanent live, fridge/battery charge |
| 13-pin | ISO 11446 | Both of the above in one connector. Pins 1–8 lighting plus common return, 9 constant live, 10 ignition-controlled live, 11 return for pin 10, 12 reserved, 13 return for pin 9 |
UK-built caravans moved to the single 13-pin connector in September 2008. Before that, a caravan needed both a 12N and a 12S socket. There is also a trap for older vehicles: the 12S wiring convention changed in September 1999, which can cause mismatches between a pre-1999 car and a later caravan.
The adapter trap — read this before you buy one
A 7-pin to 13-pin adapter fitted to a single 12N socket cannot give you reverse lights, a permanent live, or a fridge charge line. Those circuits do not exist on a 12N socket, and no adapter can create a wire that is not there. It will run the trailer’s road lighting, and that is all.
The only adapter that delivers the full 13-pin function set is a twin 7-pin (12N and 12S) to 13-pin lead — because the extra functions come from the 12S socket. If your car has only one 7-pin socket, an adapter is not the answer; rewiring is.
Dedicated versus universal wiring on modern cars
On any car with a CAN-bus electrical system — which is most cars built this century — this matters more than the price difference suggests.
A vehicle-specific wiring kit is tailored to the car in its cable lengths and connectors, and connects directly into the existing data bus. Because it talks to the car rather than splicing into it, it allows functions that a universal kit cannot: deactivating the rear parking sensors when a trailer is connected, and enabling trailer stability control through vehicle coding. Trailer sway mitigation works by using the car’s existing ESP sensors to detect swaying and braking individual wheels to correct it.
A universal kit splices into each rear light circuit with quick connectors. It will make the lights work. It will not deactivate your parking sensors, which means they will detect the towbar or trailer and alarm continuously, and it may not enable trailer stability functions at all.
On a modern car, buy the dedicated kit and have it coded properly.
Is a towbar an MOT item?
Yes. The DVSA MOT inspection manual covers it under section 6.1.6, “Coupling mechanisms and towing equipment”. The test covers:
- All coupling mechanisms and towbars at the rear of the vehicle
- The vehicle structure within 30cm of the towbar mounting points — corrosion here is a common failure
- Tow balls, with covers removed for inspection
- Couplings behind access panels
- Retractable towbars in their in-use position
Defects run from Minor — a towbar obstructing the number plate or a lamp — through Major to Dangerous. See our MOT preparation guide for the wider test.
The legal kit list
| Requirement | Detail |
|---|---|
| Trailer brakes | Required if the trailer weighs over 750kg when loaded |
| Breakaway cable or secondary coupling | Required. Engages the trailer’s brakes, or stops the trailer, if it detaches |
| Number plate | The trailer must show the same plate as the towing car — on the rearmost trailer if towing more than one |
| Towing mirrors | Required where the trailer or caravan is wider than the rear of the car. Penalty: a fine of up to £1,000 and 3 penalty points |
| Maximum trailer width | 2.55m |
| Maximum trailer length | 7m behind a vehicle of 3,500kg MAM or less |
Speed limits when towing
| Road type | Limit when towing |
|---|---|
| Single carriageway | 50 mph |
| Dual carriageway | 60 mph |
| Motorway | 60 mph |
Towing equipment worth having
Products verified against manufacturers’ own listings, August 2026. Towbars themselves are not listed here because they must be specified against your exact vehicle variant and production date.
Noseweight gauges
Milenco Precision Calibrated Noseweight Gauge (2691) — measures up to 130kg, which covers most car-and-caravan combinations.
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Milenco Precision Calibrated Ball Weight Gauge (3155) — measures up to 400kg, for heavier trailers and vehicles with a high permitted noseweight.
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Towing mirrors
Milenco Grand Aero 4 (2912 convex / 2073 flat), sold in pairs. Milenco states that all its mirrors are type approved and correctly e-marked, which matters because a towing mirror that is not type approved does not meet the requirement it is there to satisfy. Buy in pairs — the requirement applies to both sides.
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Milenco Aero 4 (2899) — the universal version, also sold as a pair.
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Adapters — pick the right one
Maypole MP602 — twin 7-pin (12N and 12S) to 13-pin. This is the one that gives you the full function set, because it draws the extras from the 12S socket. If your car has both 7-pin sockets and your caravan has a 13-pin plug, this is what you need.
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Maypole MP600 / MP6005 — single 7-pin to 13-pin. Lighting functions only. Correct for a lighting-only trailer; not sufficient for a caravan needing reverse light, permanent live or fridge charge.
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Maypole MP601 / MP6015 — 13-pin vehicle to 7-pin trailer. For a modern car towing an older trailer.
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Breakaway cable
A breakaway cable is a legal requirement on braked trailers, and the technical basis is UN Regulation 55. Cables wear and fray — replace rather than repair.
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Stabiliser
AL-KO AKS 3004 stabiliser coupling (1280484). A friction stabiliser grips the towball directly, which means the ball must be clean, dry and free of paint and grease. Worth knowing before you grease your towball out of habit — with a friction stabiliser fitted, that is exactly wrong.
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What you need to confirm a towbar fitment
- Exact model year and build date. Towbar approvals are date-ranged, and manufacturers’ finders demand it.
- Body style. Hatchback, estate and saloon versions of the same model often need different brackets.
- Engine and drivetrain. Relevant to the towing limits, and sometimes to the bracket where the exhaust or rear subframe differs.
- Whether the car has factory tow-prep. Some cars are built with the wiring harness and coding already in place, which changes the electrics kit you need.
- The VIN. The reliable route to variant and build date, and the way to settle it when a registration lookup returns more than one option.
Then check the towbar’s own approval label lists your vehicle. That label — not the retailer’s listing — is the proof.
Frequently asked questions
Do I need to take a trailer test to tow a caravan?
No. The requirement for a separate B+E test was removed on 16 December 2021. If you passed your car test on or after 1 January 1997 you may now tow a trailer up to 3,500kg MAM, and DVLA adds the category to your licence at your next renewal.
How do I find out what my car can tow?
Take the gross train weight from the VIN plate and subtract the vehicle’s maximum weight. Cross-check against the handbook, which usually gives separate braked and unbraked trailer limits.
Can I move a towbar from my old car to my new one?
Only if it is the exact same make and model. Westfalia states that a newer or older model, or a slightly different variation, may not be suitable — and the towbar’s approval label has to list your vehicle.
Will a 7-to-13 pin adapter give me reverse lights on my caravan?
Not from a single 7-pin 12N socket, no. Those circuits do not exist on a 12N connector. You need either a twin 12N-and-12S to 13-pin adapter, or the car rewired with a 13-pin socket.
Does a towbar affect my parking sensors?
It can. A vehicle-specific wiring kit that connects to the car’s data bus can deactivate the rear parking sensors when a trailer is connected. A universal kit that splices into the light circuits cannot, so the sensors will keep detecting the towbar or trailer.
Is a towbar checked at MOT?
Yes, under section 6.1.6, including the vehicle structure within 30cm of the mounting points. Retractable towbars are tested in their in-use position and towball covers are removed for inspection.
What is noseweight and how do I measure it?
It is the downward load the trailer puts on the towball, typically 50–100kg. Measure it with a noseweight gauge, with the trailer level and loaded as it will be towed. Respect the lower of the car’s limit and the towbar’s S value.
What speed can I do when towing?
50mph on a single carriageway, 60mph on a dual carriageway and 60mph on a motorway.
Related guides
- Car parts compatibility checker
- MOT preparation guide
- Car battery types explained
- What a UK car costs to maintain
How we check fitment for this guide
The licence, weight, MOT and trailer requirements on this page are taken from GOV.UK and the DVSA MOT inspection manual directly. The type-approval position comes from UN Regulation 55, and the electrical standards from the ISO specifications that define each connector. Where a widely repeated figure is a club or trade recommendation rather than law — the 85% guideline is the main one — we say so.
Towbar fitment is variant and build-date specific. Confirm against the towbar’s own approval label, which must list the vehicles it covers, and use the VIN rather than the registration alone if the car is an import or a facelift-year example. How we check fitment.
Towbar fitting and towing electrics on a CAN-bus vehicle should be carried out by a competent fitter. Incorrect installation can affect the vehicle’s braking and stability systems.
Last verified: August 2026. We review this page every six months, as licence and MOT rules change.