When you’re shopping for new wheels, there can be a lot of information to consider. One piece of information that can be the most difficult to understand (at least as it applies to practical usage for your car) is the weight of the wheels. Wheel weight can have a major impact on your vehicle, but just how much is highly dependent on what you plan to do with it, alongside one other major factor. Let’s get into it.
Generally speaking, wheel weight becomes a part of your vehicle’s overall weight. Cars that are heavier will be more difficult to get up to speed, and they’re more difficult to slow down when needed. You’ll find an impact on your overall fuel consumption, too. There are other considerations you’ll want to make though.
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Beyond the idea that heavier vehicles are harder to get up to speed and slow back down, reducing wheel weight means you’re reducing the “un-sprung” weight of your vehicle. There’s a lot of physics behind the full impact of that change, but ultimately, it means it’s easier for the suspension to do its job effectively. The wheels are the easiest and most cost-effective way to reduce un-sprung weight (the alternative is components like axles, wheel hubs, control arms, and certain driveshaft components).
Reducing the wheel weight in a performance vehicle – especially one meant to take corners, means you’ll quickly find better handling when you’re behind the wheel. In tests, drivers saw substantial improvements in lap times when they cut 12 pounds off each wheel.
Getting less mass in motion also means your acceleration will make a notable improvement. In testing, many drivers knocked nearly half a second off of their 0-60 times. That’s substantial, and certainly worth considering with a car that’s built for performance.
Cutting weight from your wheels isn’t just about the weight you remove, but the physics behind how that particular weight’s location makes your car behave on the track. It’s far more impactful than, for example, switching from your factory hood to a carbon fiber one. If performance is your goal, upgrading to lighter weight wheels can be worth every penny.
Before we dive all the way into the theoretical science behind this, we should remind you there are many factors that can affect your car’s performance and handling, whether on the road or race course. The impacts of changing and shifting wheel weight we’re talking about are by no means guarantees – there are just too many variations in cars, we can’t make those kinds of promises. That said, there are a lot of potential changes to discuss, and you should move forward with all the potential possibilities for improvement in mind.
Wheel weight in general can have an impact on your car or truck’s performance and handling characteristics. Where the weight exists in the wheel can have serious impact, though. That’s because of a little thing called rotational inertia. So what is rotational inertia, anyway?
Rotational inertia is the amount of resistance it takes something to change velocity. When it comes to wheels, it means a wheel with a higher rotational inertia needs more power to actually start moving than one with a lower rotational inertia. Rotational inertia is directly related to wheel weight, but it’s not as simple as heavier wheel equals slower car.
Rotational inertia can be dramatically affected based on how wheel weight is distributed in the construction of the wheel. Weight that is centered closer to the hub results in a much lower rotational inertia than the same amount of weight found in the rim or lip.
For a simple way to think about rotational inertia, think about spinning a small weight on a string. If the string is only a couple of inches long, it’s not particularly difficult to get the weight moving. If, on the other hand, the weight is at the end of four feet of string, it gets substantially more difficult to get it spinning.
Wheels with a high rotational inertia are resistant to moving, but we’ve already covered that. What you might not have considered is that “resistant to moving” also includes steering movements. When you reduce rotational inertia, you’ll likely feel it in your car’s steering. It will get lighter and easier to maneuver, making corners easier.
If you remember anything from high school physics, you’ll likely recall that inertia comes into play when you’re getting something to stop, just as much as it does when you’re trying to make something go. That goes back to the “changing velocity” part of the equation. Slamming on the brakes is a change in velocity, too – a negative one.
That means rotational inertia has a similar impact on braking as it does on acceleration – in theory. It can’t hurt your braking times to reduce rotational inertia. That said, it’s typically not rotational inertia that’s going to impact your vehicle’s ability to stop. It’s friction – your brakes – that will have the real say here.
Because wheel weight is rotational mass, its effect on fuel economy isn’t exactly a straightforward answer. If you’re doing a lot of city driving, full of stopping and going every day, you could see an impact on your gas mileage when you reduce your wheel weight. You’re using all that extra energy to get your car back in motion every time you stop or slow down during your drive.
If, on the other hand, you do primarily highway driving, you’ll be less likely to notice an impact. Once you get heavier wheels in motion, your car isn’t working nearly as hard to keep them at highway speeds. For many people, that could mean going an extra day between stops at the gas station – a meaningful impact that both your wallet and the environment would feel.
If you’re looking for improved performance or better gas mileage, reducing your wheel weight can be a great step in the right direction. When it comes to choosing the right wheel and tire combination for your vehicle, we know the options can be overwhelming. If you’re looking for some expert advice, we’re here to help. Call our team at 866-961-8668, and we’ll get you on the road in no time.