One of the teeth-aching disconnects of our time is the feigned obsession with MPGs on the one hand – and the very real obsession with huge wheels (and tires) on the other hand.
The two together amount to weight loss on the Burger King Plan.
Not that there’s anything wrong with big wheels as such – if that’s what you like. Just as there’s nothing wrong – as such – with Whoppers. What makes the teeth ache is people who talk about losing weight . . . and eat Whoppers.
Also people who talk about saving gas . . . who buy cars with big “rims.”
Just as a diet of Whoppers adds to your waistline by adding calories to your diet, larger wheels and tires hurt fuel efficiency because they add weight and increase rolling resistance.
But people seem to like the look – and as a result, even minivans now come with 17 and 18-inch wheels. Bigger (larger diameter) wheels than exotic high-performance cars such as Ferraris used to come with.
On Ferraris and other cars like them, there’s a solid functional reason for large-diameter wheels. Ferraris and such are performance cars – and people who buy performance cars value . . . performance. This includes faster steering response and firmer handling. Large-diameter wheels enhance all that by making possible the use of comparatively short and so stiffer sidewall tires, which flex less.
And having a wider contact patch enhances traction, which increases lateral grip threshold (how fast you can corner the car before it begins to lose traction and slide out of the corner) and improves straight-line acceleration by putting the power to the pavement – rather than up in smoke.
But there’s a price to be paid for all of that – just as there’s a price to be paid (at your waist – and possibly, your cardiologist) for dining on Whoppers every day.
Short sidewall tires result in a firmer ride, which has to be counteracted by suspension tuning. And there’s no counteracting the more rapid wear – and increased vulnerability to damage – which is part of the deal when you have a car with tall – and wide – rims fitted with short-sidewall tires.
Your car will also use more gas than it would if it were wearing smaller-size wheels and tires. See above point about weight and rolling resistance.
Which you’d think would be an important consideration to people buying cars that aren’t Ferraris.
To economy car buyers, at least.
Most new economy cars come standard with at least 16 inch wheels – the same diameter wheels that Z28 Camaros and Mustang GTs came with back in the ’80s. And all new hybrids come standard with at least 15-inch wheels, the same diameter as the wheels that came with my ’70s V8 muscle car, the Orange Barchetta (1976 Carousel Red Pontiac Trans Am).
Most new hybrids offer as optional equipment wheels as large as 18 inches, which is almost as silly as fitting a new Ferrari with 15 inch wheels.
A couple of weeks ago, I test drove the Kia Niro hybrid (reviewed here). It comes standard with 16-inch wheels, with 18-inch wheels available optionally. The effect of just changing wheel sizes on the car’s fuel economy is striking.
With the 16s, the Niro carries an EPA rating of 51 city/46 highway – which is very good. But if you buy the optional 18 inch wheel package, the mileage drops to 46 city and 40 on the highway.
That’s a difference of 5-6 MPG.
Actually, we don’t have to imagine. We can cross-shop. The Kia Niro’s cousin is the Hyundai Ioniq (reviewed here) and it shares the same basic drivetrain with the Niro. But it comes standard with 15-inch wheels.
And gets 57 city, 59 highway – a difference vs. the 18-inch-equipped Niro of 11 MPG in city driving and 19 on the highway. Some of that is due to the Ioniq’s more slipper shape – but still.
Imagine how it’d do with 14s – and very skinny, very low-rolling resistance tires.
Wait, we don’t have to imagine! Honda used to offer just such a machine – the Insight hybrid. Not the current one. The one they sold back in the early-mid 2000s. It came with a 14-inch wheel – and was capable of 70 MPG.
Granted, the original Insight was a two-seater and smaller than today’s hybrids. But the juxtaposition is interesting. The original Insight – and the fuel-sippy cars of the past, many of which achieved about the same or even better mileage than the fuel-sippiest cars of today – delivered excellent mileage. . . because they were focused on mileage.
Other considerations such as “rims” – were secondary.
Today, they’re not.
. . .
Got a question about cars – or anything else? Click on the “ask Eric” link and send ’em in!
If you like what you’ve found here please consider supporting EPautos.
PS: EPautos “Don’t be a Clover!” magnets are free to those who send in $20 or more. My latest eBook is also available for your favorite price – free! Click here. If you find it useful, consider contributing a couple of bucks!