From an aesthetic point of view, wider tyres always look better. High performance cars always use wider tyres too, so the general perception is that they offer better performance as well. On the surface, upsizing to wider tyres is a no brainer (looks AND performance combined? Sign me up!).
You might even consider “upgrading” to wider tyres on your car. However... While the idea seems exciting, you might want to think twice before doing that.
Well, wider tyres do offer certain advantages, but they also come with disadvantages – Just like everything else in the world. There is also a chance that they might not fit on your car, or perhaps your car is too weak or too light* for wider tyres.
*(Too weak = not enough power to turn the wheels; Too light = not enough weight to gain optimum grip)
Let’s go through the advantages first to understand the appeal of wide rubber.
*These advantages are listed assuming other factors of the tyre are kept constant (eg thread pattern, thread depth, tyre type, tyre material, & wheel diameter)
Advantage – Better Acceleration (for powerful cars)
Ever see a car on the drag strip? Look how big the driven wheels are on them (rear or front). There is no point in having tremendous power (engine) if it doesn’t reach the tarmac, and the drag strip testifies this.
The key thing we must note about this advantage is that the car must first offer enough (or a surplus of) power to justify the upgrade to wider tyres. If your car is underpowered, wider tyres only increase the rolling resistance, which means more unnecessary load on the engine.
Can tyres be too narrow?
Yes, of course. Your space savers are too narrow. That's why they come with a speed limit.
Advantage – Better Braking (when your brakes are too good)
Like the advantage of better acceleration, your car must first be equipped with good brakes before you even consider wider tyres.
Remember, in this argument we assume that thread pattern, thread depth, tyre type, tyre material, & wheel diameter are kept constant.
Yes, wider tyres improve braking since there is a bigger contact patch (surface area of contact with the ground). However, your brakes must be good (or too good for the tyres that you have now) first. Otherwise, the increased rotational mass of the wider tyres will only make braking a bit harder for your poor little callipers and rotors.
Advantage – Better lateral grip
When driving, you use both longitudinal and lateral grip provided by the tyres. Longitudinal grip is used when you accelerate and brake. Lateral grip is used when you turn.
Lateral grip will help you keep the car sticking to the tarmac when you hit the apex of the corner. If you’re familiar with that term (apex), you will know that this is a benefit that is rarely felt in normal driving conditions.
Advantage – Better aesthetics
Wider tyres and bigger wheels are an easy way to improve the look of your car. They make the car look more athletic and steal the attention away from unpleasant physical features of the car.
Disadvantage – higher rolling resistance
We can’t talk about wider tyre without mentioning this. Whether its upgrading to bigger wheels or wider tyres, the most significant effect is the increased rolling resistance. What this means is that wider tyres will add load to the engine.
Unless you have a powerful car that needs the extra grip, wider tyres won’t do you much good.
Disadvantage – higher fuel consumption
Higher rolling resistance = higher load to engine
Higher load to engine = higher fuel consumption
Disadvantage – Not the best for wet conditions
Now, this point is mentioned considering that a narrow and wide tyre both have a similar thread pattern, thread depth, and the vehicle weight is kept constant. Wider tyres are usually designed with sipes that remove water from the contact surface.
Narrower tyres are better in the case of driving through standing water. The higher amount of force per contact surface area (pressure) allows better water dispersal (from contact surface), thus reducing the chances of aquaplaning.
Wider tyres are a bit like the Gremlins. While they may be great in dry conditions (and ideally on a racing track), you wouldn’t want to get them wet.
Disadvantage – more expensive
If money is not a problem to you, you can just dismiss this disadvantage. Why are they more expensive? The main reason is that they aren’t produced as much as the standard-sized tyres. And then there’s the added cost of materials since you get more rubber. Being larger and heavier, they also cost more to ship.
In summary, the benefits of wider tyres can mostly be felt with a powerful car, when driving in perfect weather, and when pushed to the limits on a racing track.
There is also the appeal of better aesthetics, but this is a subjective matter. There are basically no practical benefits for daily driving especially if you’re driving an underpowered econobox.