Are wider tyres better for your vehicle?
Tuesday, 16 July 2019
The short answer is it depends on your vehicle and what you are using it for.
To really understand if it is beneficial to run wider tyres on your vehicle, we need to put our science hats on and get down and dirty with the rubber that keeps us on the road.
So, what are we actually talking about when it comes to wider tyres?
Well, I don’t suppose an explanation is really necessary, but it literally means fitting tyres to your vehicle that are wider than those with which it was fitted when it rolled out of the factory.
The width is the measurement in millimetres across the tread of the tyre (the part that grips the road).
You can find out more about tyre measurements here but, very briefly, you can tell what width tyre you have from the numbers on its sidewall.
For example, if you see the term 235/45R17, it means the tyre is 235mm wide, the height of its sidewall is 45% of the width, it is of radial construction (hence the R), and will fit a 17-inch wheel.
Tyres are designed to provide a contact patch with the road surface, and the tread pattern is there to shift any standing water and increase grip in slippery conditions.
Fitting wider tyres should increase this contact patch and therefore increase grip, right?
Unfortunately, it’s not that simple.
In perfect weather conditions, it’s likely true that fitting wider tyres will increase the grip and, therefore, improve the handling and braking characteristics of your vehicle.
But on the open road, this isn't something you are going to notice straight away, and there is a downside to wider tyres - wet weather performance.
Fitting wider tyres actually increases the likelihood of aquaplaning in wet weather conditions or on slippery surfaces as the larger tread width struggles to cut through the water.
Skinnier tyres can shift standing water much more efficiently, providing more grip in treacherous conditions.
Snow tyres are often skinnier too, as they are able to dig in through the layer of snow.
Picking tyres for your vehicle is always a compromise.
Do you go all out and buy the most expensive tyres you can in hopes they are better than cheaper tyres?
Do you fit wider tyres to increase performance in the dry but reduce wet weather performance?
You also have to factor in if they will actually fit!
Increasing the tyre width may cause them to hit the wheel wells and your turning circle may be reduced as the tyres come into contact with suspension components that the factory-fitted tyres did not.
If your vehicle is your weekend track toy, fitting larger tyres is almost a no-brainer.
However, for your average Joe Blow, fitting wider tyres to the grocery-getter to increase your chances of winning the traffic light Grand Prix could be considered a waste of money.
Your vehicle's manufacturer spent millions of dollars developing the best all round options for handling in dry and wet weather conditions, and upgrading to a wider tyre may reduce this performance. T
he saying usually goes ‘If it ain’t broke, don’t fix it!’
Finding a passion for cars from a young age, Joel carried out work experience as a mechanic whilst at school before starting an apprenticeship after finishing year 12.
After almost 10 years on the tools and in customer service, he moved into the IT realm as a Data Analyst and In-House mechanic at AutoGuru.