Load index and load capacity for camper and van wheels: how to get it right

One in three campers drives overloaded. That is what the Dutch camper club NKC found when it weighed eight hundred of them. And the weight of your camper or van ultimately rests on four (or six) points: your wheels. The number that decides whether that is safe is called the load index. In this article we explain it in full: how to read it, how to work out with your registration number what you need as a minimum, what that second value means with twin fitment, and why the wheel is just as important as the tyre.

Reading the sidewall: where is the load index?

The load index sits right after the tyre size. A typical camper tyre shows, for example, this:

That 116 does not mean "116 kilos" but refers to a fixed table: 116 stands for 1.250 kg per tyre. The full, official table is below.

The load index table (official RDW/ETRTO values)

These are the legal values as the RDW, the Dutch vehicle authority, applies them at the Dutch periodic APK inspection (Annex 4 to Article 50), for the range you will find on vans and campers:

Highlighted: LI 116, the most common value on 16 inch camper tyres (225/75 R16).

How to calculate what you need as a minimum

The legal calculation rule is surprisingly simple, and it works per axle:

1. Look up the maximum axle load. It is listed in the vehicle register: enter your registration number at ovi.rdw.nl and check the axle loads for the front and rear axle. Always calculate with the rear axle, as on vans and campers it is almost always allowed to carry the heaviest load.
2. Divide the axle load by the number of tyres on that axle. Two tyres with standard fitment, four with twin fitment.
3. Find the first load index in the table that can handle that weight. No tyre on that axle may sit below it.

Example: a Ducato Maxi camper with a rear axle load of 2.400 kg: 2.400 ÷ 2 = 1.200 kg per tyre. LI 114 (1.180 kg) is then just short; you need at least LI 115, and the common 116 sits comfortably above that. Two rules from the RDW inspection manual worth remembering: a stronger tyre on the left never compensates for an underrated tyre on the right, and on commercial vehicles a load index that is too low is simply a fail point at the APK inspection.

That second value: single or twin fitment

Many van and camper tyres carry a double notation, such as 116/114. The first number applies to single fitment (one tyre per wheel position), the second to twin fitment: two tyres side by side on the same axle, as on heavy campers and light trucks. On larger tyres you will see the same in text: "MAX LOAD SINGLE" and "MAX LOAD DUAL".

Why is each tyre allowed to carry less with twin fitment? Two reasons: because of the camber of the road surface the outer wheel is loaded slightly differently from the inner one, and the construction deliberately keeps a reserve in case one tyre of the pair loses pressure. The other one then has to cope alone for a while. In the Netherlands this rule is laid down in law: with twin fitment the second, lower value always applies.

The forgotten half: the load capacity of the wheel

Almost everyone checks the tyre, almost no one checks the wheel. Yet the wheel is regularly the weakest link. To illustrate: the original Fiat wheels on a Ducato Light chassis are approved up to exactly 1.000 kg per wheel, while the tyres on that same chassis can often handle 1.300 kg or more. On the Heavy/Maxi chassis Fiat works with 1.250 kg per wheel. If you uprate your camper and only look at the tyres, you may well be driving on wheels that are not allowed to carry the new weight.

Good wheels for vans and campers are tested with a generous margin: in the rolling test a wheel is loaded with 2,5 times its nominal load capacity. Our wheels for this segment are load-rated and for many models test reports are available on request. Never fit a passenger car wheel on a heavy van or camper: it is simply not made for this.

CP tyres and tyre pressure: the final piece

There is a separate tyre class for campers: CP (camping). It exists for good reason: a camper carries a lot of weight continuously, has a high centre of gravity, a long overhang and often an unevenly distributed load (water tank, bike carrier). CP tyres have a reinforced carcass for this and are made to run at higher pressure: the ETRTO recommendation for the rear axle of a camper is 5,5 bar. And the whole load capacity story only holds at the correct pressure: a heavily loaded camper running 20 percent underinflated is already in the danger zone.

The five mistakes we see most often

• Driving overloaded. A third of the campers that were weighed turned out to be too heavy; among integrated campers almost half. Weigh your camper once in full holiday trim and you will know where you stand.
• Checking only the tyre and forgetting the wheel, while it is often precisely the wheel that is rated for less than the tyre.
• Calculating with the total weight divided by four instead of per axle. The rear axle almost always carries more.
• Fitting passenger car parts. A passenger car tyre or wheel is not built for continuous high loads.
• Buying the cheapest tyre online without an LI check. It saves a few tens of euros, until the APK inspector or your insurer takes a look. And take note: work is underway to make the load index an APK checkpoint for passenger cars too.

In doubt? We calculate it for you, free of charge

Send your registration number via WhatsApp and we will look up the axle loads, calculate the minimum load index and recommend a wheel and tyre combination that safely handles your weight. If you choose fitting at our workshop in Nieuwegein, we set the correct pressure straight away and configure TPMS where applicable. See also our fitting service.

Want to read more? Also see which wheel size to choose for your Ducato camper and all Ducato, Boxer and Jumper variants at a glance.