Monday, July 6, 2020

Death of the spare tire


Spare tires are already on their way out.  But perhaps in the future buying a tire without a wheel will be an unusual thing.

Tire technology really hasn't changed much in the last half-century or so.   You can go to your local tire store with a car from the 1930s or 40s and probably find a tire that fits it. Of course, you may have to buy an inner tube. But any car from the 1950s onward can be easily fitted with most modern tires.

The basic design of a tire rim and the portion of the tire - the bead - that cinches on to this rim hasn't really changed much over the years.   I enjoy reading old car brochures, and Dodge touted back in the 1950s that they came up with a new rim design that prevented the tire from falling off the rim in the event of a blowout. This was quickly adopted by other car manufacturers and is pretty standard today. But not much has changed since then.

The tubeless tire was probably the next big innovation, and it really didn't change much, other than to eliminate the inner tube. Once we got rid of spoke wheels, it was a pretty simple matter to eliminate the inner tube, and have the tire seat and seal to the rim.

From a technology point of view, the advent of radial tires in the United States in the 1970s was one of the biggest safety and handling improvements in tire technology.  Radials had been available in Europe years before, but it took a long time for them to replace old bias-ply tires in America.

Flat tires were a huge problem for early automobiles.   The reason most cars came with multiple spare tires in the brass era, was that you didn't get very far when driving before having a flat.  A friend of mine reports that his grandfather recalls driving his Maxwell from Syracuse to Cazenovia (about 20 miles) and having only two flat tires on the way!  They thought that was pretty decent - usually they had three or four.

Car tires were pretty flimsy back then and changing them was something you got used to doing. There's a reason why cars back then had at least one or two spare tire sometimes three or four if you were traveling cross-country.  Early motoring was not for the feint of heart.

But nylon cords, fiberglass belts, and eventually, steel belts, have made tires more reliable and less prone to puncture or blowouts. The biggest problem in tire wear is the owners - few check tire pressures, and low pressure is the number one cause of blowouts.   Tire load capacity is affected by tire pressure - and not linearly!  A tire at 50% of rated pressure handles less than 50% of rated load, which often is less than the load placed on it.  Sidewalls flex and heat up and eventually blow out.

Tire pressure sensor monitors have helped with this problem.  New cars have them (in the US) by law.  Some, like the ones on my truck, tell you the actual pressure, others simply give you a low-pressure warning.   Most people don't understand that tire pressure changes with temperature and load, so get freaked out when the tires change pressure unevenly while they drive, which is one reason most makers merely display a "low pressure" warning instead of an actual reading.

But such sensors are cheap now.  I bought a set for the trailer and a monitor for a total of $20 or so from eBay - and for the most part it works, too.


The run-flat tire is nothing new - some designs date back to the 1930's!

Some car companies experimented with run-flat tires starting in the 1930s.  Goodyear had limited success with its "double eagle" tires - basically a tire-within-a-tire.  Others came with an inner solid rubber donut that was attached to the rim using special tools. When the tire went flat, the car would then ride on this rubber donut inside the flat tire. The tire would be destroyed of course, but it meant you could drive to the gas station without having to change a tire by the side of the road.

Back then, the selling point for run-flats was safety - not spinning out due to a blowout, but not being robbed or raped by the side of the road if you had a flat (most commercials for these types of tires featured vulnerable damsels-in-distress).  But with the energy crises of the 1970's, cars got smaller and weight became an issue.  The spare tire - used less and less - was seen as something of an anachronism.  (Volkswagen even ran a car commercial based on this - calling the full-sized spare tire they provided a "coelacanth" or ancient fish - a living fossil).  The donut spare and the inflatable spare became popular as space-saving and weight-saving measures.

Are full-sized spare tires really living fossils?  People thought so even years back!

And of course, tire repair shops were once plentiful across the country and in every town. When I was a kid, part of your coming-of-age experience was your dad showing you how to jack up the car and change a tire.   Of course, we lived up in snow country, so we had to put on snow tires every year, so taking tires on and off the car was something we were quite familiar with.

Today, so many insurance companies and car companies offer "roadside assistance" and more and more people have no idea how to change a tire or even where the jack is. We see people sitting by the side of the road waiting for a tow truck to change the tire for them, rather than relying on a good old American know-how and self-reliance and changing it themselves. It's kind of sad to see this.

Worse yet, we see people riding on "donut" spares doing 70 miles-an-hour for days or weeks at a time.  And often we see these cars with their donut spares blown out, by the side of the road, and the owner walking.  I guess if you ride on the donut spare that long, you don't have "roadside assistance".

Improvements in tire technology have made flat tires pretty much a thing of the past. I've owned cars and drove them for over a hundred thousand miles and never had a flat tire.  In fact, I've worn the tires out twice without ever having a nail go through a tire or have a puncture or anything. Of course, I keep track of my tire pressures and check them regularly so I never have to worry about blowouts due to low tire pressure.  I also try to rotate my tires to even out wear and extend tire life.

I also keep one of those tire repair kits which includes tire repair plugs in a special tool. This is handy if a nail goes through the tire. Gas stations used to do these kind of repairs but now they claim they no longer can do them to reliability issues. Now they either require that you buy a new tire or they remove the tire from the rim and then install a patch from the inside

Tire life has improved as well, over time.  Old bias-ply tires lasted maybe 20,000 to 30,000 miles.  Today, you can easily get over 50,000 miles out of a set of good radials, provided they don't dry-rot due to old age.  And thanks to new tire treadwear ratings, you can get a pretty good idea of how long a set of tires you buy will last.

Some companies have tried to improve basic tire technology in the past. Michelin came out with a tire called the TRX, which used special beads which locked into the rim, apparently with a different diameter on each side of the wheel.  Unfortunately, this meant you had to have special tires and wheels matched together as well as a special store with a specially trained technician with a special machine to change the tires. It was briefly popular in the early 80s and then faded from the scene.

Not to be discouraged by that failure, Michelin tried again with PAX tires, which ran-flat and also required special rims.  Both TRX and PAX tires are out of production, so if you had a car with these, you had to buy new standard rims and tires, once the old ones wore out.  The PAX tire was offered initially on cars like Bentleys and Mercedes. Although it did work its way down to lowly Honda minivans as an option. But again, quickly disappeared from the scene as nobody wanted to go to a special tire store or be limited in tire selections. Mounting and unmounting the tires required special tools and special knowledge, which leaves you in a pickle, when travelling cross-country.

So today, tires are pretty much the same as they were back in the 1950s, at least from the mounting perspective. Backward-compatibility wins out over high-tech superiority. A lesson for Engineers, everywhere!

The spare tire, course, has been on its way out for a long time. Starting in the early seventies, companies offered inflatable spare tires that came with a little can of compressed air that you can use to blow up the tire. The reasoning behind it was to reduce weight in the trunk of the car and thus improve gas mileage and also increase trunk space. These quickly gave way to the donut tire which was designed for temporary use only - although tell that to people in the inner city or the trailer park. These are usually running a very high pressure and are really only good for 50 miles or so, enough to get you to the nearest gas station.

(By the way, in the 1990's they sold little cans of compressed butane or propane to inflate your tires if they had a puncture. The can also included some sealant to attempt to seal the puncture. The problem with those kits was that the gas was flammable and if somebody worked on the tire later on it could explode. I believe they've been pulled from the market since then.)

Other, high performance cars have no spare tire whatsoever. Our M roaster had no provision for a spare tire because the well where the spare tire would normally go is taken up by the enormous mufflers on the car.  Is they  gave you a little 12 volt pump and a can of sealant goo and were told to try our best to pump the tire back up.  In the decade that I own that car we never had a flat tire, of course. But it for you did, you probably have to flatbed the car to a dealer to have it replaced.  The local garage doesn't carry P245/40 R17 tires in stock.   So you have to hope you don't get a flat, if you have prescription tires and no spare

And speaking of prescription tires, that is another aspect of this progression in tire technology - the unintended performance tire customer.  Many people buying a Mercedes or BMW or even a more plebeian Toyota with a sport package, are chagrined to discover their car requires expensive low-profile tires, come replacement time.  Some are even directional, meaning they are meant for only one-side of the car.  If you have staggered, directional tires, no two tires interchange on the car!   The standard tires on lesser cars can be found at Walmart for a few bucks.  Specialty tires sometimes have to be special-ordered, and replacing four tires on some of these cars can cost thousands of dollars - often more than the resale value of the car, towards the end of its life.

By the way, it is interesting how many blog entries I have made in the last ten years about tires:








Tire Treadwear Ratings 
Just to name a few...
It struck me as interesting that tire technology in terms of how the tires are attached to the rims really hasn't changed over the years. Some tire companies have tried to come up with better mounting technology, but since it wasn't widely adopted it quickly faded from the scene. What is interesting is that we still have tires and wheels sold as separate accessories for your car. Your tires wear out after 30,000 to 50,000 miles and you go to a tire store and they unmount tires and mount new ones on your existing rims.

The other scenarios this is less the case. If you blow a trailer tire, you can either have a new tire mounted or you could buy a tire and rim combination for not a lot more money, and in some cases, even less. You can go to Walmart or the local boating store and see pre-mounted tires and rims stacked up. If you blow out the tire on your boat trailer you just go buy a new one, stick it on there and throw away the old rim.  Why not do this for car tires?

There are reasons, of course.  Different cars have different wheel sizes, offsets, lug spacing, and whatnot.  People buy fancy rims for their cars, but less so for trailers (mea culpa, the Escape has aluminum wheels).   But aluminum wheels, once thought of as fancy racing accessories are pretty much standard on many cars today.    But could that change?

As technology changes, how we use technology changes. I noted before that LED lights are being sold as "bulbs" using the Edison thread developed at the turn of the last century. I suspect in the coming years you will see fewer "bulbs" for sale and more and more LEDs built into lamps, so that when the  LED burns out, you merely throw away the lamp. Of course, you could put in more LEDs that are necessary, and as each one burns out, another one could be switched on automatically using a circuit built into the device. I suspect how lamps are built will change dramatically due to the longevity of LED technology.  It makes no sense to have the bulbs removable anymore for automotive, or for home use.

This won't happen overnight.  Not today or tomorrow, but eventually.  And in the automotive sector, it already is the case - LED lamps are sold as fixtures, not as "bulbs" in many cases, particularly for marker lamps and the like.  Home use is taking longer to employ, but it is slowly happening.

In fact, I already own such fixtures. When we remodeled our garage and laundry room we put up 48 inch "shop lights" which we bought at the Wholesale Club. They look and act just like the old fluorescent shop lights of yore, but are in fact LED fixtures. And the LED part of the fixture is not removable. So if theses lights ever burn out, the only solution you have is to throw them in the trash and buy a new one. Again, this makes sense, as it is too expensive to try to repair one of these things as the hourly wage of repair labor is much higher than manufacturing labor, particularly in this country.

It remains to be seen whether electric cars will take off and whether these self-driving cars will take off - although it seems the technology is nearly mature enough. Some pundits argue that in the future we won't even own our cars, but will just rent them via some Uber-like app and go where we want to go.   Once we get where we want to go, the car will then leave and take somebody else somewhere, and we don't have to worry about it. This will be a godsend for the drunk drivers of America - but not to the person riding the car after they've puked in it.

But it raises the question, what will cars look like if people don't actually own them?  A lot of what sells cars is emotion and style. People buy a Mustang or a Camaro or Challenger because it looks tough and cool, like the old muscle cars from the 1960s. People like the animal-like grills that look like they're ready to take a bite out of my next car. Similarly with pickup trucks people like the big trucker look so they can play pretend trucker.  But if you don't actually own the vehicle what shape would it take?  Would anybody care what the thing looked like if they didn't own it?  Even if you owned it, would you want a car that looked "sporty" when you are in fact, not behind the wheel (because there is no wheel?).

And with self-driving cars, some kind of run-flat technology would be essential, as there would be no tire-changing by the side of the road.   The car would sense if tire pressures were low and return to the garage for service.  If a blowout occurred, it could run on run-flats to a safe location, the passengers disembark to a different self-driving car, and an automated tow truck would pick up the crippled unit.

In such an environment, maybe these fancy TRX or PAX-type rims and tires might work - if they provided better safety and run-flat capabilities.  Backward-compatibility for tires and rims may no longer be an issue, when people no longer own their own cars (for the vast majority of people).   The real owners of these new cars will value dependability and reliability - and safety - over appearance or style.   Alloy rims with fancy styling may be out.  Whitewall tires or raised white letters may become extinct.   Tires and rims on such vehicles will have all the charm as those on a city bus or a forklift.  Steel rims may make a comeback.

It might entirely be possible this will happen even without autonomous cars. When your tires wear out, instead of buying a new tires and having them mounted and balanced, you might just go to the dealer and he'll put four new tires and rims on it in about 20 minutes.   They will come pre-mounted and pre-balanced at the factory, so the dealer doesn't have to hire a tire technician to mount them and doesn't have to worry about balancing problems.  He won't have to buy the associated equipment as well.

This also means that we don't have to have people mounting tires, which means we could also use this more esoteric tire rim technology that failed in the past.  While a failure in the marketplace, such rims tended to retain their tires even during blowouts and thus were much safer. This would particularly be useful for autonomous cars which might not be able to handle a sudden blow out at highway speed.

And perhaps that's why these earlier rim technologies failed, in that they tried to sell the tire separately from the rims, and they were very difficult to mount without special tools and skills.  If the dealers sold the tire and rim packages together, owners could just buy a tire and rim when they blew out a tire and not have to deal with the uncertainties of where to get the tire repaired.   Of course, that wouldn't have worked back in the 1980's, when people were content with cheaper mount-and-balance technologies.   But in the future?

The spare tire is dead.   And I suspect the idea of mounting tires at the local tire shop may die in the future.   It already has, for trailer tires.