The Incredible Disappearing Spare Tire: It's All About Weight and Space

Last Updated Jul 21, 2011 3:22 PM EDT

Where's the spare? The Chevy Cruze Eco fills the tire well with nothing more than this inflator device.
In the early days of motoring, you could buy cars with "twin sidemounts," which meant not one but two spare tires. It's been downhill ever since for the driver's peace of mind, and now the traditional spare is disappearing entirely as standard equipment. Who hasn't experienced a shiver contemplating a blowout on a rainy night, at the mercy of one of those "space saver" temporary tires or, worse, some kind of inflatable botch job?

Away they go
Until a few years ago, nearly all cars came with full-sized spares, but today they're not available on 13 percent of new cars and the trend is accelerating. According to, 38 percent fewer cars have full-sized spares than did five years ago. This isn't a cost-cutting maneuver -- it's a bid to save both weight and space as cars get smaller and more fuel efficient.

Another factor is that wheels are getting bigger (often 16 inches are more) and there's just nowhere to put them. That's why the full-sized spare is more likely to be seen on large SUVs and trucks these days.

Cars that now come without big spares include the Hyundai Elantra (how do you think it achieved 40 mpg on the highway?), Chevrolet Cruze and Malibu, Buick Regal GS and (depending on model) the Kia Optima.

Even if you understand the reason for it (and applaud the fuel savings), you can also mourn the loss of the full spare tire. Identical to the other tires, it can be rotated by the conscientious motorist, and you can even leave it on for months after a flat while getting around to putting it back in the trunk. Plus, the alternatives are lousy -- the space saver tire is strictly for emergencies, and it's unlikely to be speed rated, which means you have to take it easy at 55mph or slower. The tire often comes with a warning sticker threatening dire consequences if you leave it on for more than 50 miles.

Fixing the flat instead
Many cars, including the Chevy Cruze Eco test car I have now, offer no spare at all -- just a flat-fixing kit. Sometimes car owners don't know this, and are left distraught and searching for the spare when an emergency pops up. Don't even get me started on the whole inflatable thing. I got stranded in a parking garage, on Halloween night, when I tried in vain to inflate a tire on my Saturn Vue Hybrid with an anemic can of tire sealer/inflator -- don't these things have shelf lives?

One other trick carmakers are using is to equip cars with run-flat tires that keep the car on the road for short distances after punctures, but they're expensive and also only good for short distances.
It looks like that old teenage rite of passage -- learning how to change a flat -- is going to have to be updated with an ABC on carmakers' cheap fixes.

What else is coming off cars?
Cars as we know them are slowly losing distinguishing features that have been around since the early days of motoring -- all either to save weight or increase aerodynamics. For instance, there's a big fat target on the outside rear-view mirror because it sticks out into the airstream and hurts the coefficient of drag.

Engineers at Tesla Motors told me they want to get rid of side mirrors on next year's Model S sedan, but they're still visible in the spy shots. The advantages, Tesla says, include not only saving weight but also less noise and better-looking cars. The major disadvantage is that the video camera/screen you'd likely have instead could fail.

Also likely to go: radio antennas (they've already largely disappeared), CD players (you'll bring and plug in your own digital device), protruding door handles, ashtrays (also largely vanished already) and even glass windows (polycarbonate plastic has half the weight). How much longer will glove boxes have doors?

Don Edmunds of told the Los Angeles Times:

Manufacturers do a lot of little things to squeeze more of the last bits of toothpaste out of the tube. Weight reduction is just one of them, and spare tires are a tempting target.
Indeed they are, and that's why we have to cope with the infernal half-measures known as run-flat tires, flat-fix kits and temporary spares.


Photo: Jim Motavalli