Car first or caravan first?
Either order works, and each one fixes half the sums.
Buying the van first fixes its ATM (Aggregate Trailer Mass), and buying the car first fixes the limits the van must fit under.
Updated . 9 min read • Buying Guide
Either order works: buying the van first fixes its ATM, buying the car first sets a weight ceiling instead.
Compare the van's ATM and ball weight with the car's tow rating, towbar rating, towball limit, GVM (Gross Vehicle Mass) and GCM (Gross Combination Mass).
- Van first - fixes the loaded weight (and hands you a shortlist of cars rated to tow it)
- Car first - sets a weight ceiling (and every van above it comes off the list before you see it)
A tow car and a caravan look like two purchases. They behave like one, because the numbers on each of them have to agree with the numbers on the other.
Whichever one you buy first fixes half of that arithmetic, and the second purchase then has to fit around it.
Why the order matters at all
Three numbers do most of the work here, and they belong to different parts of the rig.
- ATM (Aggregate Trailer Mass), on the caravan. The most the loaded van is allowed to weigh. The ATM does not change with how you tow the van.
- Braked towing capacity, on the car. The most that car is rated to pull. The van's ATM has to sit inside it.
- GCM, across both. The cap on the loaded car and the loaded van together. On many cars it is lower than the car's GVM (Gross Vehicle Mass) and its towing capacity added up. That is how a rig can be inside the first two and over the third.
Ball weight and the car's towball limit sit alongside those. The download the van puts on the towbar is part of the van's ATM, and it also comes out of the car's payload. It competes with the passengers, the dog and everything in the boot, and it has to sit under the towball limit.
Buy the van first and you have fixed the ATM, and the ball weight within a range, so the car has to be found to suit them. Buy the car first and you have fixed the capacity and the payload, so the van has to be found to suit those.
The full explanation of each figure is in caravan weights explained, and the compliance plate guide shows where the van's figures are stamped and where the car's are kept.
How buying the van first plays out
This is the layout-led route. You work out how you want to live in the thing, which fixes the floorplan, which fixes the ATM.
From that point the car search is no longer open-ended. It is a shortlist of whatever is rated to tow that ATM with GCM left over, and the shortlist can be short.
What it fixes
You get the van you actually chose. For anyone who wants a specific layout, a full off-road build or a particular length, that is the point of going this way round.
It also means the van decides the car. If your car is not rated for the van, the van has made the car decision too. Budget the changeover as part of the van purchase.
Where it bites
A van you cannot tow is a van sitting in someone else's yard. New vans are usually built to a slot, so there is a handover date, and the car has to be sorted by it rather than after it.
A private-sale van is the sharper version of the same problem, because the seller wants it gone the day you pay.
Checking a specific van against a specific car
Put the van's published ATM and ball weight against the car's published figures and see what margin is left.
Open the tow calculatorHow buying the car first plays out
There are two versions of this, and they feel very different from the inside.
The car you already own
Most people are in this one without having decided to be. The ceiling already exists, in the car's owner's manual, whether or not anyone has looked at it yet.
Read those figures early. They tell you which part of the market you are shopping in before you fall for a van outside it. A car with a GVM over 4,500kg needs a heavier licence than a car licence.
A tow car bought for the job, new or used
Here you set the ceiling deliberately, and the van search becomes everything underneath it. The trade is that you choose the car before you know what it will pull. The headroom you leave is a guess about a van you have not picked yet.
What it rules out
Every van above the ceiling is off the list, whatever its layout and however well it suits you otherwise. You stop spending weekends on vans the car cannot tow. You also never see the ones just over the line.
The honest way to see what a ceiling actually leaves you is to look at the vans under it before you commit to the car.
See what a given car can tow
Pick a make and model and get every checked range inside its tow rating, towball limit and GCM.
Browse caravans by tow vehicleTrade-ins, and the overlap nobody plans for
Changing both assets usually means two things going out as well as two coming in, at two different yards, on two dates that have no reason to line up on their own.
The overlap is where the money goes, mostly on small costs that add up.
The four dates worth writing down together
- • The van's handover date, which is the day you need a tow car that suits it
- • The day the old car goes, since selling it early leaves you without one
- • The day the next car actually lands, which is not always the day it was ordered for
- • The day an old van has to be gone, if one is going
Insurance and registration have their own start dates. Both need to be in place from the day each one is yours.
Storage is the other one. A van collected before the car is ready has to sit somewhere, and paid storage is easy to leave out of the plan.
None of this is complicated. Treat the two purchases as one timeline.
Buying a car that only just clears the van
A car chosen to exactly clear the van in front of you is cheaper today, and it fixes your ceiling for as long as you own it.
A tight margin does not stay where you left it.
The margin gets spent
A van leaves the factory at tare and puts on weight from there. Water, gas, batteries, an awning, tools, food and the bikes on the back all live in the gap between tare and ATM, and that gap is what payload means.
The same thing happens to the car. Ball weight, passengers, the dog and everything in the tub or the boot come out of the car's payload together, and a rig that measures fine empty is not the rig you tow.
The heavier van later
Some buyers move to something bigger within a few years, as the family grows or the trips get longer. A car matched tightly to today's van has no room for that, so the next van makes it a car decision as well, and one purchase becomes two.
Headroom left in the car today is the thing that buys the option later. Whether it is worth paying for now is a call only you can make, because it depends on how likely that second van is.
Work out what is left for your gear
Payload is the difference between a van's tare and its ATM, and it fills up faster than most people expect.
Open the payload calculatorCommon questions
Should you buy the caravan or the tow car first?
Both orders are common, and each one fixes a different side of the same arithmetic. Buying the van first fixes the ATM, which sets the towing capacity the car has to meet and turns the car search into a shortlist. Buying the car first fixes the ceiling, so the van search is everything that sits under it. Which order suits comes down to which of the two you are least willing to compromise on, the floorplan or the car in the driveway.
Does the caravan's ATM decide what tow car you need?
It sets the floor for it. The car's braked towing capacity has to cover the van's ATM. The van's ball weight has to fit inside what is left of the car's payload once people and gear are in, and under the car's towball limit. The GCM (gross combination mass) has to cover the loaded car and loaded van together. A car can be inside its towing capacity and still be over its towball limit or GCM, so check all four.
Can you tow a caravan with the car you already have?
That depends on figures in the car's owner's manual. The braked towing capacity, towball limit, GVM and GCM are all there. The towbar and towball carry their own ratings. Our tow calculator takes those numbers and shows the margins.
What happens if you buy a car that only just clears the van?
The margin gets spent. A van gains weight from tare towards its ATM as you load water, gas and gear. Its ball weight counts against the car's payload, alongside passengers and luggage. A tight match leaves nothing for a heavier van later, so upgrading the van becomes a car decision as well.
How do trade-ins work when you are changing both the car and the van?
They are two separate transactions at two different yards, and the dates rarely line up on their own. You need a tow car on handover day. A car sold early leaves a gap, and a van collected before the car is sorted has to sit somewhere. Write the van handover date and the car date next to each other early, and the overlap does not turn into storage fees.
Either way round, on one screen
If the van is the fixed point
- • The layout you want sets the ATM
- • The ATM sets the towing capacity the car has to meet
- • The car shortlist is whatever clears that with GCM to spare
- • The car has to be sorted before handover day
If the car is the fixed point
- • The car's published figures set the ceiling before you shop
- • Every van above the ceiling is off the list, whatever the layout
- • Ball weight comes out of the car's payload, with passengers and gear
- • Headroom left today leaves room for a heavier van later
Both orders work, and both are common. The one that goes badly is the one where the two purchases were treated as unrelated until the week of handover.
Whichever end you start from, check the van's figures against the car's owner's manual and towbar label before anything is signed. Next steps either way: the can I tow it check, the tow calculator, caravans for your car, or the start-to-finish buying guide.