When winter arrives, when you change diameter to have smaller tires: in addition to being economical, this solution has the advantage of giving thinner tires, which in winter guarantees more grip on the ground and therefore more safety. On the other hand, it is usual to change back to summer tires and at the same time to larger rims, so as to have wider tires, and thus increase stability on the ground. Also, it can be simply a desire, a question of aesthetics, the change from steel rims to aluminum rims, the recent purchase of a car that just wants to be pampered, etc. We then wonder how far we can go, within the limits of the law and the approvals.
The indications on your vehicle!
On the inside of the door, next to the pressure indications, inside the tank, etc. But above all, in the vehicle’s technical booklet. Yes, it is! That’s where you should start looking! Know that you will find on your vehicle the mounts approved by the manufacturer. Choosing one of the dimensions you find there is a guarantee that you will not have any surprises and that you will pass the technical inspection without any problems, and that you will be insured. But you may want more. Yes, I do know you! You thought you could fit 18″!
This video can explain it more:
In fact, the legislation also authorizes transformations and offers the possibility to equip vehicles with tires different from those recommended by the manufacturer. It should be remembered that the outer diameter of the tire must be identical. The table of dimensional equivalences previously published by the manufacturers has now been replaced by an official table published by Travaux de Normalization du Pneumatique French, which is considered authentic by the authorities and the technical control.
From a technical point of view as well as from a regulatory point of view, 3 precautions must be taken:
The load and speed ratings must be equal to or higher than those of the original equipment. This is an absolute must for the equipment to be legal and for the vehicle to be covered by insurance. The rim width must be compatible with the tire width. The manufacturers have a minimum – maximum rim width table corresponding to each tire size. The intermediate nominal value is the recommended width so that the tire is ideally positioned on the rim and can work in the best conditions. The fender passages must be able to accommodate a wider tire. Last check, our rim search engine for your vehicle, coordinated with our vehicle search engine: you enter the model of your vehicle, then you choose a rim diameter, then the tires.
