Pardon the audacity of an almost 72-year-old for asking, but why have car-makers developed a fascination for cars with the combination of a larger diameter rim coupled with a lower profile tire? In reading entries on car owner forums, I get the impression that while such combinations may look ‘cool’ to style and marketing types, they are distinctly impractical on the pot-hole prone streets of many US cities. The lower the profile of the tire, the greater is the likelihood that the sidewall will be damaged beyond repair and perhaps the rim, too, when the owner encounters the inevitable and perhaps unavoidable (think in-motion bumper-to-bumper traffic) pothole.
Such a combination is especially egregious in a vehicle in that growing class that is sold unequipped with even a doughnut spare and jack. My first experience with such a combination is the Nissan Leaf (P205/55R16.) Perhaps some MIT trained engineer will be able to explain how this combination improves the miles/kWhr. I believe it is the case that a P205/70R 15 would have the same circumference and hence revolutions/mile. I think it would decrease the risk of a pothole flat and consequent tow and tire replacement.
Consumers sometimes have a “fashion over function” mentality. This is simply a good example of this. You can’t blame the automakers too much for providing what people are buying right now.
You’re correct that these tires are often impractical. Although low-profile tires do offer better handling, the tradeoffs generally don’t make sense, in my opinion. Something in the medium-profile range would probably provide all the handling most people need while reducing the drawbacks quite a bit.
For what it’s worth, when purchasing a new car, it’s often possible to trade a lower-profile setup for a higher-profile setup from the base model of that car.
I don’t think a R205/55R16 is one of the major offenders on large wheel on small sidewall tire front. In general, a larger wheel allows for a larger disk brake making for more efficient braking and more stopping power. Mostly the very large wheels are way bigger than the brakes and it is marketing and cool factor and perhaps some handling advantages to the combination. You give up ride quality and durability to get the cool look.
On a Leaf they are looking for the best rolling resistance they can obtain so you get more miles before needing a recharge. The stiffer sidewall means less flexing and less rolling resistance. In the Leaf the tire is selected by performance criteria over the “cool” look.
I think you have hit on the reason, but are just having trouble internalizing it.
Cars are sold based on emotion - not logic. Big wheels look cool and that triggers the emotion. The car designers know that. They don’t care if that creates a problem - that’s for the engineers to fix!
And here I am going to disagree with Uncle Turbo - All this business about rolling resistance can be applied to ANY tire. Low profile tires aren’t any better for RR than high profile tires.
I didn’t mean to say that low profile tires have less rolling resistance in general. I meant to say that the particular tires selected for OEM fitting from the factory on the Leaf (a total electric car) will be a low RR tire. I don’t really see the tire size given by the OP as one of the ridiculously low profile tires that I’ve seen mounted on things like Cadillac Escalades.
Just like 200 hp used to be ‘high’ (now I guess it’s 500 hp), ‘low profile’ is no longer 70 or 60 series. 50 series seems to be the point below which tire and wheel damage becomes more common.
IMAGE-IMAGE-IMAGE, the three most important facets in marketing cars. And most other devises and appliances. The Ford Mustang was nothing but a repackaged Falcon but set sales records. Only emasculated men drive mini vans. And the horsepower wars are getting silly. A true 300 horsepower engine would pull a loaded 18 wheeler at a sustained speed in excess of 70 mph. It is unlikely that the Nissan V-6 engine could do that. But then we seem to be VAIN-VAIN-VAIN. And the marketers can play us for all we are worth. The political marketers are sizing us up and picking the IMAGE to paint their man to get our attention and vote with little regard to his real qualifications. Given the choice of a 177 I-6 Mustang or a 260 V-8 Falcon most people went with the Mustang. I hope we do better in up coming elections.
I’ve seen wheel sizes go down and up. My first car, a 1947 Pontiac, had 6.50 X 16 tires. My next car, a 1955 Pontiac had 7.10 x 15 tires. My 1965 Rambler Classic 550 had 6.95 x 14 tires. I thought that the Rambler had a better size than the Ford Falcon which had 13 inch wheels. The 1957 Buick bucked the trend and stayed with 15 inch wheels. The reason was that someone in the design studio thought that the car “looked better” with 15 inch wheels as opposed to 14 inch wheels. I thought I would never see 17" wheel sizes as that on my 1950 Chevrolet 1 ton pickup truck, but my 2011 Toyota Sienna has 17" wheels. Maybe we have hit the peak again and wheel sizes will go down.
I drive a minivan by necessity since I manage a chamber orchestra and am always transporting musicians and their instruments. I thought I would like to have a Mazda Miata, but Mrs. Triedaq thinks that the Miata is a car for wimps. She thinks if I want a sports car that I should find an Austin Healy Sprite. She says that real men don’t mind getting out and pushing their cars out of traffic when they break down.
They’re good for DRY PAVEMENT traction and handling. They’re bad for every other kind of condition. As other point out the handling advatage is seldom utilized by those wuho buy these cars. But they are eye-catching.
I do, however, suspect that a wheel/tire combination that provides a specific tread width and rolling circumference might be lighter if using a lager alloy wheel and lower aspect ratio tire than it would be using a smaller wheel and larger aspect ratio tire to obtain the same tread width and rolling circumference. That lower rotating mass would contribute to higher mileage.
I’ve never confiirmed this theory, but would like to. If I had a tire shop I’d probably weigh the two options and find out once and for all.
There is a “Rent-N-Ride” retailer near me. They market the outrageous wheel/tire package as a rent to own deal and apparently they are making money. Most of the wheels are on older Crown Vics, Caprices, and older SUVs often worth less than the price of the new wheels/tires. It never ceases to amaze me just how gullible people can be. People who are unable to hold back a few hundred dollars each month to save for a down payment on a home will obligate themselves to pay $50 to $100 per week to look ‘cool’ as they drive home to the housing projects. And often I see cars that have been jacked to make room for the HUGE RIMZ, rolling on 4 miss matched wheels and even mini spares.
Two big practical reasons are, cars are safer handlers with these low profile tires, and the advent of traction and stability control has put a huge premium on oversized brake discs to dissipate the heat. Both necessitates larger wheels. So, the oversized ones for looks…yuk ! But there is an overall trend to larger wheels for valid reasons.
I guess it depends on what your game is. For the many people that drive SUVs only on flat, paved roads, low profile tires are probably not much worse than regular profile tires and rims. That would never work for you and Mike, dagosa. But if I wanted a SUV , it wouldn’t make any difference from a practical standpoint.
It’s all about visual impact and in some cases when installed on ultra-hi performance cars, these cars will deliver slightly better skid-pad side G performance numbers that automotive magazine editors place great importance on when doing comparison tests against similar cars…
This only works on perfectly smooth surfaces, where the wheels and tires stay on the road…On a slightly uneven surface, with little ability to absorb impact, the 10-20-30 aspect ratio tires get bounced off the road and traction momentarily lost, making the car jumpy and skittery on all but perfect pavement…
Also, most drivers quickly tire of the very harsh ride and twitchy steering produced by the super-low-profile tire / wheel “systems” being offered, never mind the pot-hole damage…
Jt…“it wouldn’t make any difference from a practical standpoint” …I hear what you are saying from a visual point of view if that’s why you would buy an SUV. I can’t speak for Mike but for me…lFrom a practical point of view, everything that real SuVs are made for, suffers from exceptionally low profile tires.
Off roading, heavy towing, rough roads, snow/ mud traction etc, all that true SuVs are designed for, are better performed on standard rim tires then the aftermarket low profiles. I would NEVER own an SUV for looks alone. If they can’t do what they were designed to do as well with after market tires, why bother. I would have no use for them.
But jt , you are absolutely right. Many SUVs are just fat mall station wagons in use and their owners impress each other with 20 plus inch rims.
I had no idea I would trigger this response. Gulp!
Can I as how many readers have seen this article?
Read carefully the last 5 paragraphs where we are told that “repair kits (no spare) are standard on 14% of the models available” and that the trend is growing.
For those who want to save time, here are the results for a Google search of “no spare tire.”