A quick Q&A for mixing low profile tyres with alloys

One of the most popular upgrades drivers make to give their cars more kerb appeal is switching to a set of alloy wheels.

A set of alloys adds value and performance to your car. They look sportier, more expensive and add a level of sophistication and cool to any model.

But is it as easy as taking your existing wheels off and dropping a new set on?

Well, in some cases it can be. If you’re making a direct switch for a set of alloys that have the same measurements as your existing steel wheels, or they are a direct same-manufacturer upgrade, then you shouldn’t have much trouble at all.

However, if you want a bigger, sportier-looking wheel, you will have to make adjustments.

What can go wrong when upgrading to alloys?

There are several components whose operation is directly dependent on their integration with your wheels.


The first, and incredibly important, are your brakes. If the new wheels don’t have the same internal space and dimensions as the existing ones, then the brake callipers might not fit in at all, never mind operate correctly.

Tyre sizes

If you’re going for a bigger wheel, then that means less space in the wheel arch for tyres. You’ll have to consider the width of the wheel and what tyres you can fit to still house them safely without rubbing or sticking out too far.

Fuel consumption and your speedometer

The computer in your car that measures your speed, distance and fuel consumption uses pre-determined information to make its calculations. The critical figure in those calculations is the circumference of your tyre. The circumference is the distance travelled during one rotation of your wheels. If that measurement changes, then it will throw all those other vital measurements out.

A change to your light settings

Even the slightest change in tyre and wheel size can throw out your headlight settings. You must have them recalibrated to stay within legal parameters.

Why choose a low profile tyre conversion?

Apart from looking every inch the stylish upgrade, what are the real benefits of low profile tyres? And, by comparison, what are the most common low profile tyre problems. Here’s our list of low profile tyres pros and cons.

Low profile tyre advantages

  • Better grip
  • Shorter braking distances
  • Increased stability during cornering
  • Additional control
  • Less sideways tilting

Low profile tyre disadvantages

  • More susceptible to damage
  • Wheels, suspension and chassis components are more vulnerable to damage
  • Enhanced wear due to expected driving styles and manufacture requirements
  • Harder, less comfortable ride

Wheel and tyre calculations for upsizing alloys

Although we would never guarantee that adhering to the following guidelines would provide a flawless and seamless conversion, they’re a fairly standard rule of thumb to think about when considering the change.

The most popular upsizing provides calculations of increasing wheel size while decreasing the tyre profile, yet, keeping the tyre circumference the same.

Plus Zero

A Plus Zero conversion keeps the wheel diameter the same but combines it with a larger width tyre and a smaller aspect ratio (profile).

Plus One

Plus One increases your wheel diameter by 1” combined with a tyre with a one-step lower aspect ratio (profile).

When increasing your car’s wheel rim diameter by 1 inch: increase the tyre section width by 10mm and decrease the tyre aspect ratio by 10 points.

Plus Two

Plus Two increases the wheel diameter by 2” and combines it with a tyre with a two-step lower aspect ratio (profile).

When increasing your car’s wheel rim diameter by 2 inches: increase the tyre section width by 20mm and decrease the tyre aspect ratio by 20 points.

Sizing up your new alloys

Sadly, it’s rarely as easy as picking a set of wheels one or two inches bigger than those you’re currently running. Unless your new wheels are manufactured specifically for your make and model, then there are a lot of different measurements to consider:

  • Offset – the distance from the hub-mount to the true centre of the wheel
  • Pitch circle diameter – the diameter of the mounting bolt formation
  • Bolt patterns – the number and arrangement of bolts used to fasten the wheel in place
  • Centre bore – the size of the hole that slides over your car’s wheel mounting hub
  • Rim width – the width of the wheel from side to side

Most cars can only manage a few per cent change in the essential areas, so getting the right set of wheels for your car from the vast amount of aftermarket designs, brands and styles available is quite the challenge.

SUV and off-road low profile tyre options

With the increased chances of damage to wheels, suspension, chassis components and to the tyres themselves, it seems like a strange choice for an off-road tyre.

However, many of the SUV vehicles we see today never make it off-road. SUVs and their crossover counterparts are becoming the fastest growing family car option in years due to their robust build, safety features and performance in all weather.

Many of the low-profile off-road tyres won’t be ideally suited to true off-roading but will work as a good winter tyre on a larger rim. Again, it’s a case of understanding what the right tyre for the job is and where it’s going to be fitted.

If you’re not sure, always ask an expert

There’s so much to consider when upgrading your wheels. Despite everything you’ve heard about alloys and improved driving performance, it isn’t always the case.

How your car handles depends on precise measurements and calibration. Introducing any new part that affects that could just as easily have a negative effect as a positive one.

A change in weight, width or even the grip can affect suspension performance, steering and more.

We’d always advise you choose a qualified expert to make sure the job is carried out properly, and rigorously tested, once fitted.

Choose Fixter for your professional alloy wheel and low profile tyre conversion

Our mechanics are experts with all the knowledge and experience to make sure you stay safe as well as achieving great value. We’re here to guide you through every step, making sure you know which wheels will perform for your car and the best low profile tyres for your conversion.