Caravan & Motorhome Glossary
This glossary explains every key term you need to understand when buying, towing, or driving a caravan, motorhome, or campervan in the UK. From MTPLM and kerbweight to C1 licences and damp checks.
Weights & Limits
MTPLM
MTPLM stands for Maximum Technically Permissible Laden Mass. It is the maximum permitted loaded weight of a caravan or motorhome, set by the manufacturer, and includes the vehicle plus all payload and contents. Use MTPLM, not the empty weight, when checking whether a car can tow a caravan safely and legally.
MiRO
MiRO (Mass in Running Order) is the weight of a caravan as it leaves the factory, including standard equipment, a full gas cylinder, and essential fluids. But without personal belongings or passengers.
MRO
MRO (Mass in Running Order) is the older term for the unladen weight of a leisure vehicle. It has been largely replaced by MiRO for caravans, but you may still see it on older spec sheets.
GVW
GVW (Gross Vehicle Weight) is the maximum permissible weight of a motorhome or campervan including everything on board. Passengers, fuel, water, and belongings. It determines which driving licence you need.
MAM
MAM (Maximum Authorised Mass) is another term for GVW. The maximum weight a motorhome or commercial vehicle can legally weigh. It is the figure used by DVLA to determine licence categories.
Payload
Payload is the weight you have available for personal belongings, passengers, water, gas, and accessories. It equals MTPLM minus MiRO (for caravans) or GVW minus unladen weight (for motorhomes).
User Payload
User payload is the weight remaining after factory-fitted optional extras are deducted from total payload. It represents what you actually have left for personal gear.
Towing
GTW
GTW (Gross Train Weight) is the maximum combined weight of your tow car plus your caravan or trailer, fully loaded. It is set by the car manufacturer and must not be exceeded.
Towing Capacity
Towing capacity (also called maximum braked towing limit) is the heaviest trailer or caravan your car can legally tow. It is set by the car manufacturer and shown on the VIN plate.
Kerbweight
Kerbweight is the weight of your car with a full tank of fuel, all standard fluids, and no passengers or luggage. It is the base figure used to calculate the 85% towing rule.
Noseweight
Noseweight is the downward force a caravan exerts on the towball when hitched up. UK guidance is to aim for around 5 to 7 percent of the caravan's actual laden weight, while staying inside the car and towbar limits, for stable towing.
85% Rule
The 85% rule is a widely recommended towing safety guideline: your caravan's MTPLM should not exceed 85% of your car's kerbweight for confident, stable towing.
Licences
C1 Licence
A C1 licence allows you to drive vehicles between 3,500kg and 7,500kg. Including most larger motorhomes. If you passed your car test after 1 January 1997, you do not have C1 automatically.
Category B Licence
A standard UK Category B car licence generally lets you drive a vehicle up to 3,500kg MAM and tow a trailer within published trailer rules. For motorhomes this usually means staying at or below a 3,500kg GVW unless you also hold C1.
Layouts & Body Types
Fixed Bed
A fixed bed is a permanent sleeping area that does not need to be made up or converted from a seating area. It is the most popular layout feature in modern caravans and motorhomes.
Island Bed
An island bed is a fixed double bed with walk-around access on both sides, like a bed at home. It is the most popular premium layout in modern caravans.
Transverse Bed
A transverse bed runs across the width of the caravan rather than along its length. This space-efficient layout allows a fixed bed in shorter, more towable caravans.
Bunk Bed Layout
Bunk bed layouts provide stacked sleeping berths. Usually for children. Allowing families to sleep 4-6 in a standard-length caravan or motorhome.
End Washroom
An end washroom is a full-width bathroom at the rear of a caravan or motorhome, offering the most spacious shower and toilet arrangement available in a leisure vehicle.
Side Dinette
A side dinette is a booth-style seating area along one wall of a caravan or motorhome, typically with a table that lowers to create an additional sleeping berth.
Coachbuilt
A coachbuilt motorhome has a purpose-built living area constructed on a cab chassis. It offers more interior space than a panel van conversion, with an overcab bed or drop-down bed adding extra sleeping capacity.
A-Class
An A-class motorhome has a fully integrated cab. The driving area is part of the habitation body, not a standard van cab. It offers the most spacious and premium motorhome experience.
Low-Profile
A low-profile motorhome is a coachbuilt without the overcab bed area, giving a sleeker, more aerodynamic profile. It trades the overcab sleeping space for better fuel economy and easier driving.
Van Conversion
A van conversion (campervan) is a panel van. Typically a VW Transporter, Ford Transit, or Fiat Ducato. Converted into a motorhome with sleeping, cooking, and sometimes washing facilities.
Inspections & Checks
Damp Check
A damp check uses a moisture meter to test caravan and motorhome walls, floor, and roof for water ingress. It is the single most important pre-purchase inspection on any used leisure vehicle and should be a non-negotiable for every used buyer.
Habitation Check
A habitation check, sometimes called a habitation service, is the annual safety inspection of the living area of a caravan or motorhome. It covers gas, 240V and 12V electrics, water, ventilation, fire safety, and damp, and is separate from a mechanical service or MOT.
Service History
Service history for a caravan or motorhome includes habitation checks, damp reports, mechanical servicing, and any repair records. A full service history significantly increases resale value.
Compliance & Legal
Motor Caravan Status
Motor caravan status means DVLA has classified a vehicle as a "motor caravan" rather than a panel van. This affects tax class, insurance, and whether the vehicle is exempt from certain commercial vehicle restrictions.
ULEZ
ULEZ, the Ultra Low Emission Zone, is a London charging area where vehicles that do not meet set Euro emission standards pay a daily fee. For motorhome and campervan buyers it usually means checking that a diesel base vehicle meets Euro 6, with rules confirmed on the TfL website.