Size of the tyres

Question

I have bought a VW Passat b7 Variant. 1.6D. It came with (all four tyres) following size: 215/55 - 16.

In the vehicle booklet, it says 195/60 R16.

I a bit confused here. I have seen many other same Passats on the road with smaller diameter tyres. Following the logic, my 215 diameter boils down to this: - Looks better - Consumes more fuel

Is there any other advantage, besides looks better? Should I go for 195/55?

PS I guess, now is a bit too late to change it, since I bought Dunlop SportsMaxx RT as a Summer tyres for my car. Price was extremely good, that is why.

But, I would like to know more information.

Thanks :)

Answer 1

The diameter of both tires is about the same - they differ by 0.4% only. (Try this calculator)

The first number is the with in millimeters. This, multiplied with the second number and divided by 100 gives the sidewall height in millimeters: 195*60/100=117; 215*55/100=118.

It is true that wide tires are less fuel efficient:

• There is more rubber being deformed while driving, causing more friction.
• Turning a wide tire also causes more friction
• A wider wheel is heavier, and the plus in mass sits at the outer diameter, which increased the energy needed to accelerate the wheel a lot

On the other side, wide tires provide more grip, not only when accelerating, but also in curves and when braking. This is not only a benefit for sportive drivers, but also for safety for every driver.

Since fuel consumption does not rise that much, simply stick with the old tire size. The saved fuel will hardly outweigh the costs and as said, the wide tires offer more safety.

By the way, it's quite standard today that only a single size is mentioned in the registration documents, while maybe the manual gives a full list of allowed sizes. This applies for Germany (since you have a VW), but I don't know it's handled in other countries.