Changing Wheel Size: What You Need To Consider

So, you have decided you’re going to get a new set of wheels, and you want to change the spec from OE. This can either be a change in rim diameter, or in width. But, what should you consider when changing wheel size? Well, in this blog we explore the considerations that you need to take into account when deciding.

This is the fourth instalment of a series dedicated to wheels and tyres. So, if you see anything you’re unsure on, refer back here and click-through to find out more:

Increasing The Rim Size

Increasing the rim size is probably the most common change people make in regards to altering their wheel sizes. Going slightly bigger is usually done to fill the arch gap a little more, or just because people may prefer the bigger look. An example of this is going from a 17” rim, to an 18” rim – going slightly bigger can make a difference.

Of course you can go bigger, but you need to be conscious of the rolling radius of the wheel and tyre. It is crucial to keep the rolling radius as close to OE as possible. If you make your rolling radius larger in comparison to what the manufacturer set in place, this can negatively impact your car in three ways:

  • The car’s speedometer will under-read, so you will be going faster than what is actually displayed in front of you! 
  • Your car’s acceleration would be dulled slightly, because of the gearing change this would introduce. 
  • And lastly, a larger rolling radius will make the car sit higher – unless you opt to lower its suspension too.

If you know you’ll be affecting your rolling radius, it is important to always calculate your new radius, comparing it back to OE spec. Previously in this blog series we have covered this, telling you how to work out the rolling radius of your current wheels and tyres, and on a new set, so that you can compare and check any differences. However, we are always on hand to help you. Here at Demon Tweeks, we have a dedicated team of experienced wheel & tyre salespersons that can assist you in finding the right fitment for your car, feel free to contact us. 

Decreasing The Rim Size

Smaller rims have never been as popular as large ones, but there is a lot to be said for them in the right situation. Larger rims will generally have lower profile tyres, which don’t compress very much through corners. A decreased rim size can use a higher profile tyre for more comfort, or to protect your bigger wheels from potholes. This combination makes a great option for winter wheels.

As with making your wheel rim larger, you also need to be conscious of your rolling radius when making the wheel smaller. This can encounter the opposite problems to making it larger:

  • The car will sit lower, creating potential ground clearance issues.
  • Again, your speedometer won’t be accurate, this time it will over-read. So, you will be going slower than your speedo says. 
  • But the main consideration is making sure you don’t go too small that the wheel can’t fit because of the brake calliper and/or drums. This applies especially on performance models with bigger OE brakes. 

Increasing The Wheel Width

Who doesn’t love seeing wide wheels? Going slightly wider can help fill arches, giving you the fitment that you are looking for. Sometimes OE wheels sit further in the wheel arch than people like, widening the wheel will help make it sit further out. However, you will need to check the offset of the wheels to make sure they will sit where you intend them to, and make sure the wheel doesn’t obstruct anything. Going wider on certain styles of wheels, can result in a slightly more concave look.  

Clearance

No, unfortunately not a clearance sale, you need to make sure that the new wheel doesn’t contact the brake calliper, the suspension, wheel arch or anything inside the wheel arch. By changing the rim diameter, wheel width and/or the offset, there is a chance the wheel may make contact with other parts of the car. Thankfully, there are solutions on the market in some scenarios before deciding that the size just doesn’t fit:

  • Spacers – If a new wheel is contacting the suspension or the brake calliper, you can purchase spacers to make the wheel sit slightly further out. 
  • Arch Rolling – If your new wheel is rubbing against the wheel arch, either on its own or because of spacers, you can have your arches professionally rolled to give you clearance. 
  • Camber – Adjusting the camber can allow your wheel to sit inside the wheel arch without touching, but be careful adjusting your camber. You will need to make sure it doesn’t cause you to make contact with other parts of your car inside the wheel arch. The downside camber has, is the wear it causes on tyres. 
  • Coilovers – If you have height adjustable coilovers and they are set pretty low, you can raise the coilovers slightly to give the clearance you need, but also the fitment you are after. 

Unfortunately, sometimes some wheels just don’t fit, they are made in specifications that wouldn’t work for certain vehicles. At this point, it would be a different brand or wheel design that is required. 

Tyres

Whenever you are changing your wheel diameter or width, you will need to review your tyre size and make sure to get new tyres that are suitable for the new wheels. You will need to consider the rolling radius again, to make sure that the new wheels and tyres are as close to the OE rolling radius as possible. 

Demon Tweeks and How We Can Help You

We are not just a website, we have a dedicated wheels & tyres sales team that are on hand to help you find the wheels you are looking for – and in the correct fitment. Built on over 50 years of experience and expertise, we have access to a wide range of popular brands. Our team will be able to help you find a wheel design in a fitment you need. Whether it’s for a hot hatch, super car, race car or van, they will be able to help you. The team also has access to creating custom wheels – so it’s well worth speaking to them about your needs. 

Every set of wheels we sell are supplied with a free fitting kit, including bolts and spigot rings (if required). After the purchase of your new wheels, we will contact you to ask for your vehicle details. This is to make sure you receive the correct wheel bolts and spigot rings required. Not only will we make sure your new wheels will fit your vehicle, but we can also offer anything additional to ensure this, like spacers.

If you purchase a set of wheels, as well as four new tyres for them in one transaction from Demon Tweeks, the team can mount, valve and balance the tyres to the wheels at no extra cost. Additionally, we can deliver them to you like this, meaning that along with the free fitting kit, your wheels would arrive ready for you to fit. If you live close enough to us in Wrexham – or you don’t mind a road trip to our treasure trove of a showroom, we can fit the wheels & tyres for you in our fitting centre.

More Info…

Our team has created blogs to help you on your modification journey, if you want to discover more about wheels & tyres, checkout the blogs below;

If you still have questions you can call or email us and speak to our expert sales team, we will be more than happy to assist you. 

Looking for the latest performance parts and accessories perfect for your vehicle? Check out our wide range from top brands.

Come and visit us at our store, showroom and fitting centre in Wrexham, for a better look at what we have on offer.

Want to know more about our story? Learn about who we are and why we’ve been driven by passion for over 50 years.

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