Alloy wheels – the wheel deal

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Why do some drivers spend thousands of pounds on alloy wheels for their cars?  Is it all about looks, or is there a technical reason behind it?  And how do different size wheels affect the way your car drives?

The wheels on your car have a tough job.  As well as transferring power from the engine to the road and steering you in the direction you’d like to go (in conjunction with the four tyres wrapped around them), the wheels have to maintain their perfectly round shape to deliver you a smooth ride, despite being bounced over speed humps, through potholes and crunched up against kerbs during poorly-judged parking manoeuvres.

On many cars, especially high-performance models, alloy wheels may also aid cooling to the brakes to make sure the car stops safely under hard driving.  So how do different wheels affect the way your car drives?

Alloy wheels are replacing steel wheels across the industry

Lower-priced new cars, and many older cars, will come standard with wheels made from steel.  Steel is the metal of choice for most parts of a car, as it is cheap and can be made into different shapes quite easily, so it has always been an obvious choice to use for wheels.  But more and more cars are now equipped with wheels made from aluminium alloys, which are stronger and lighter than steel.

An alloy wheel will be much lighter than a steel wheel of the same size, which improves the car’s ride and handling as there is less weight bouncing around for the suspension to cope with and less weight for you to steer when you turn the wheel.

An alloy wheel is also stronger than a steel wheel, which means it will flex less around corners, helping the car to handle better.  However, a very big shock (such as hitting a pothole) is more likely to crack or shatter an alloy wheel, whereas a steel wheel will flex and absorb some of the impact, making it less likely to break.

Alloy wheels also tend to be stylised and polished, whereas steel wheels would rust unless treated and painted, and are usually covered with a decorative plastic trim (you know, the kind you inevitably see lying by the side of the road after they get knocked off), so a set of alloy wheels usually enhances the look of a car.

You should also read: Caring for your alloy wheels

Alloy wheels – is bigger always better?

alloy-wheels-ride-handling-performance-the-car-expertMost cars will give you the option of paying more money to have larger alloy wheels fitted.  On the car, however, the total rolling height of the wheel and tyre must remain the same, so a larger wheel means a lower profile (thinner) tyre.  In the photo to the left we have a 15-inch wheel (left), a 16-inch wheel (centre) and a 17-inch wheel (right), all mounted in tyres to fit the same car.  If you look at the three wheels, you will see that the overall height of each wheel/tyre unit is the same, but the 17-inch wheel has a much ‘thinner’ tyre than the 15-inch wheel.

Being constructed from rubber, the tyre flexes and absorbs a lot of the small impact of bumps in the road, effectively forming part of the car’s suspension. A lower profile tyre has less rubber in the sidewall to flex and soak up the bumps, so a larger wheel/thinner tyre combination will give you a firmer ride, making the car feel noticeably bumpier.  However, less flex and wobble will mean improved handling as the car changes direction through a corner or under braking.

But the real, and simple, reason that most people pay lots of money for bigger wheels is for the looks – although don’t expect expensive alloy wheels to add much to the car’s resale value down the track.  I used to have an Audi A5 with 20-inch alloy wheels (standard was 17-inch).  The large wheels meant the tyres were extremely low profile, so hitting a pothole or going over a speed hump was – literally – a painful experience, and sometimes it felt like the car had no suspension at all.  But it looked fantastic…

Audi A5 with 20-inch alloy wheelsRecommended reading:

Do big alloy wheels crack more easily?  The Car Expert answers a reader’s question about the fragility of big alloys.
Which optional extras are worth paying for?  It’s easy to rack up thousands of pounds in options on a new car, but which are actually worth it?

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Stuart Masson
Stuart Masson
Stuart is the Editorial Director of our suite of sites: The Car Expert, The Van Expert and The Truck Expert. Originally from Australia, Stuart has had a passion for cars and the automotive industry for over thirty years. He spent a decade in automotive retail, and now works tirelessly to help car buyers by providing independent and impartial advice.

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  1. Stuart, I have a 2016 Renault Kadjar 1.6 TDi (with the 4×4 option). She came to me with 19″ rims and 225/45 tyres. I recently did a trip on gravel roads and it shook the car to bits. I also had a very expensive flat due to the low profile tyres. I have been asking around at tyre dealers to hear if I can change the tyres to be less low profile on the current 19″ rims but have not been getting any answers other than “No”. Being a woman may have something to do with their reply, but I would like to make sure. Why would a vehicle with 4×4 capabilities have such limitations with regard to tyres? Perhaps you can give me some constructive advice.

  2. I am considering buying a set of alloys with winter tyres from a C class Mercedes to fit to my A class Mercedes. The wheel and tyre sizes are the same, and will physically fit the wheel well without problems. The only difference is the wheel offset (ET43 instead of ET49). This will result in a positive scrub radius of 6 mm, compared to a scrub radius of zero with the original wheels. Will this cause a significant problem with the car’s handling?

    • Hi Colin. It could well make a difference, but it may also be illegal. Check with a wheel/tyre supplier, as they should be able to check against tables to advise whether that offset is OK for your car.

  3. Hi Stuart
    I have just gotten a gold tsi 63 plate and it has standard 15 wheels on I would like to change them to 16″ alloys
    Would that be possible? And if so can I use the tyres I have on the car already as there like new and put them on the alloys?

    • Hi Amie. Yes, you can fit 16-inch wheels to your car. You will need to make sure that the wheels are suitable for your model Golf (there are a number of measurements which must be correct, not simply that the wheels physically fit on the hubs).

      You will not be able to use your existing 15-inch tyres, as they will not fit the 16-inch wheels. Either you try and sell them, or keep your current wheels on until the tyres have worn down more so you are getting value out of them.

  4. Hi Stuart i have a Renault megane cabriolet 2008 1.6
    The rims are 17 inch
    But i would like to change them to 18 inch
    With low profile tires.
    What u recommend..?
    Do you think i am not going to have a problem with them..?

    • Hi Jhonny. If the car came standard with 17-inch wheels, then changing to 18-inch shouldn’t be a problem as long as they are a correct fit for that make and model. You can expect that the ride will be firmer on the larger wheels and lower-profile tyres, but I couldn’t say whether it will be significantly different.

      Speak to reputable wheel suppliers to make sure you are getting the correct size and specification wheels to suit your car, to make sure it is legal and safe.

    • Hi Paul. It was over five years ago now, so I can’t remember. The wheels were a factory option, so it would have been whatever tyres Audi specified with them.

    • Yes, it should be possible, unless you have very large brakes which are too big for 15" wheels to fit around (unlikely on a MINI). A MINI dealer should be able to advise on which official wheels will fit. If you are looking at aftermarket wheels, you can use the dimensions of the original 15" wheels as a guide as to what specifications you will need.

  5. Hi, Having problems with 18" wheels cracking on my Mercedes c220cdi 2009 so frustrating. Was advised 17" would be less likely to crack is this good advice please and is there anyone else out there with the same problems Paul Holt

  6. hi stuart i have my car finance for 6 month now or 7 and i was wonder if i can hold my payments for 3 moths cause i got something more important to pay ?even if i can pay longer three months but ill will continue after 3 months?what i should do ?thank you thomas

  7. Do you get better mpg with smaller wheels with bigger tyres? I do a lot of motorway miles so currently playing around with various configurations on manufactures websites for a frugal but decent looking car .

    • The diameter (usually 15" to 18") is probably less important than the tyre width when it comes to fuel economy, as wider tyres will create more drag. However, manufacturers calculate their recommended tyre and wheel sizes on a number of criteria, with safety and roadholding being obviously the most important.

  8. Awesome article Stuart !..It affirms what I already thought. I live in Nigeria, and I had a choice to buy a Range Rover with 20" rims or 22" rims, turns out the one with the 22" rims was cheaper due to mileage difference, although the 22" rims looked cool and flashier, roads in Nigeria are not so smooth, so it made sense to pay more to have standard thicker tyres to complement the work my suspension was going to be doing. Thanks for this !

  9. Hi I have a mazda 6. I had my alloys replaced by mazda before the car was 2 years old as each alloy had bubbles or flaws. Less 3 years later and the alloys are showing corrosion and flaws again.
    How long should alloys last? Is this normal?

    • Hi Cindy. Superficial corrosion isn't a reason for concern, other than cosmetically. The wheels of your car operate under very harsh conditions compared to the rest of the car's exterior, dealing with heat from brakes, very corrosive brake dust as well as water/mud/snow – all while rotating at high speed and being shocked constantly by potholes/speed humps/bumps and so on.

      It is likely that the paint or coating that Mazda used on the wheels hasn't adequately protected the wheels from the corrosive effects of the brake pad material. If the 'flaws' you are talking about are more serious and affect the integrity of the wheel's structure, then that's a different problem.

  10. Hi, I currently drive a Golf with 16" alloys, but am considering trading for one with 15" alloys. I'm wondering if I can expect to notice much difference in handling around bends etc.?

    • Hi Máire. All other things being equal (ie – your old Golf being absolutely identical to the new Golf apart from the wheels), you shouldn't notice much difference. If you are getting a different model Golf (eg – trading a Mk6 for a Mk7), then there will be other factors which will affect the handling more than the wheel size.

  11. I had 15 inch wheels on Astra originally but then brought 17 inch wheels however the centre does not fit properly and there is a gap, what do you recommend?

  12. Hi iv currently got 15 inch alloys on my peugeot 207, and looking to upgrade to 19 inch, it’s a big step but do you think that will be alright? I thought yes maybe a 16″ or 17″ inch would be fine but 19″ inch is a bigger alloy and smaller tyre. Thanks.

    • That would sound like a terrible idea for many reasons. Not only would it ruin your ride and handling, but you’d probably end up with wheels and tyres that are worth more than the car. Your insurance premium would also increase significantly. And I’m not sure it would even be legal to run 19s on that car; you’d need to check with a reputable tyre/wheel shop.

  13. Hi, i bought a mercedes last year which already had 20 inch rims on it. Its a c class and the tyre size is 235/30 zr20 88y. These are all round the car however i recently took my car to mercedes and they reckon my rear tyres have been stretched to fit the wheels only at the rear, im a bit confused, could i have larger wheels at the back and if so, how can i know what size tyres i need for them. I had a blow out last week and just got the same size tyre fitted as im clueless.
    neil browne uk

    • Hi Neil. From what you’ve said, I assume that the rear wheels are wider than the front, so the rear tyres are not quite wide enough for the wheels but the fronts are ok.

      A good tyre shop would be able to tell you the width of the wheels and what tyres should be fitted. If you don’t understand what they mean, keep asking questions until you do. A good business will happily explain how it all works, as well as what wheels & tyres you are (and are not) allowed to fit to your car.

  14. My Ford Fiesta has 195/45/R16 tyres… I am struggling to find winter tyres in this size so my question is can I change to a 15 inch rim and if so what size tyres do I need? Thank you in advance.

    • Hi Mandy. Yes you can run 15″ winter tyres and your tyre retailer can specify which sizes will fit. Of course, you will have to buy new wheels as well, so it may be a relatively expensive exercise.

  15. Hi Stuart

    I am planning to buy Fiat Punto Evo which comes with both 15 &16 inch alloy i don’t like looks for 16 also spare wheel is 15 inch steel so i wanted to know what difference will i notice if i switch to 15. any downgrade on performance part. Car will be used for daily compute and some long trips 2-3 times in a year and driving style is normal. Also what are the benefit & loss of switching from 16 to 15 and vice-verse.


    • The same car will ride slighty better on 15″ wheels than 16″ wheels, although the handling won’t be quite as sharp. For most uses it will be slightly more comfortable on the smaller wheels.

      The spare wheel can be used with either size wheel, but not as a permanent replacement as its handling characteristics will be different to the alloy wheels.

  16. Given the popularity of winter tyres nowadays is it feasible to keep alloys for summer only and have steel wheels with winter tyres fitted. Swapping the alloys/summer tyres for the steel/winter tyres once the road temperature settles in low for the winter.? I have 20″ alloys but could fit 19 or 18″ steels for the winter ? I drive a 2011 Jaguar XJ Is this feasible?

    • Yes it is absolutely feasible and many people do just that. You need to make sure that the winter wheels & tyres you are fitting are suitable for your car – Jaguar will have specific requirements for the size and specification of any wheels you fit to your XJ, which must be adhered to. They may not approve steel wheels, but you’d need to check with a Jaguar dealer.

    • It depends on a number of factors: the tyre, the wheel & suspension, the car and the road. All of these components interact all the time, so changing any one of them will affect the others.

      As a rule, a lower profile tyre (less sidewall thickness) make the ride firmer and the handling sharper, and a higher profile tyre (greater sidewall thickness) gives the reverse. But it is usually more complex than that.

  17. With the state of roads where I live (New York), alloys just get shredded on curbs and broken bitumen. It cost me a load to replace two wheels broken in a big rut last month, makes me so angry.

  18. Is there any great benefit in spending a lot of money for top-of-the-range tyres compared to more modestly priced tyres? What exactly are you getting on a £300 tyre that you don’t on a £100 tyre? Thank you.

    • Like most things in life, you get what you pay for. More expensive tyres use higher-quality materials and are rated for higher loadings (eg – higher speeds, greater performance). They will generally provide better roadholding, although may not provide any increase in comfort. I will hopefully writing a blog on tyres fairly soon, so stay tuned!

  19. You would think that car makers would have managed to optimise their suspension for bigger wheels by now. It’s not as though bigger wheels are a new thing!

  20. Hi Confused,

    Tyres are very important to a car’s safety and performance, but it’s another can of worms altogether and I’ll hopefully get around to it soon! In short, tyres are just like most things – you get what you pay for. But whether the most-expensive tyres are that much better than the next-most -expensive depends on the tyres and on your car.

    As a starting point, find out which tyre or tyres are standard equipment for your car and look at the prices of those. If they were good enough for the manufacturer to put on the car in the first place, they should be good enough for you now. If they don’t make that tyre anymore (just like cars, they get replaced from time to time), there should be a newer model of that tyre.

  21. How much should I spend on tyres for my car? The local tyre shop always tells me that the £200 tyres are much safer than the £60 tyres is this true or are they trying to overcharge me. Thank you

  22. Hi Wendi,

    From a cosmetic perspective, it all comes down to whether you like the look of the car with the upgraded wheels. Try and make sure they show you a car with the wheels on, if possible, rather than just a photo. Manufacturers often use photoshop to make wheels look bigger in brochures, and they often look less impressive when you see them for real!

    From a technical perspective, the best thing to do is firstly test drive a Camry with the normal wheels and then drive a Camry with the more expensive wheels on the same road immediately afterwards. If you think it feels better, it’s worth it. If you don’t notice any difference, or find that it makes it too bumpy, save your money and stick with the standard wheels.

  23. Does it make enough difference to be noticeable and therefore worth the extra cost? I am in America and am looking at a Toyota Camry, and I don’t know if I should pay $350 extra for the premium wheels. Do u think its worth the money?

What are your thoughts? Let us know below.