It seems that a lot of motorists never think much about the space-saver spare tires fitted to many modern vehicles, and abuse them far beyond their design limits when they use them. I learned that when I went to a local tire dealer to replace my twelve-year-old donut tire, which was showing signs of oxidization as the rubber perished.
According to the dealer, any tire is supposed to be replaced after nine to ten years on the wheel, including donut spare tires. The problem is that so many spare tires are mounted underneath the vehicle, where they're hard to see, that they don't even get their pressure topped up, much less inspected for wear. People seem to forget they exist. The assistant dealing with my car said that he's had several incidents where vehicle owners had a flat and tried to put on their spare, only to find it was as flat as a pancake. To make matters worse, some of them then tried to repair their spare tires using cans of tire sealant refill, sold at many auto dealers and supermarkets. Trouble is, those cans are designed to pressurize full-size tires, not a donut spare with its much smaller internal volume; so they inflate the latter too much, which - given perished rubber or weak spots - can rupture again almost immediately.
Another problem is that regular car wheels are manufactured, reinforced and stressed to handle forces such as acceleration, cornering, minor bumps and potholes, etc. On the other hand, donut spare wheels are produced by simply stamping the wheel out of sheet metal. They're not designed for extreme use. The vehicle manufacturers warn buyers about that, recommending a maximum speed of 50 mph and maximum distance of not more than 50 miles. In other words, the donut spare is designed to get the vehicle to a place where it can be repaired, and no further. However, many drivers seem to regard them as interchangeable with the "main" wheels and tires, using them for days and weeks on end, and running at normal highway speeds. Inevitably, many donut spares that are abused in that fashion will fail on the wheel, and perhaps cause a serious accident in the process. Apparently some drivers have even tried to sue the donut spare manufacturer, on the grounds that the wheel and/or tire "failed" or "was defective". When the facts emerge, and it becomes clear that the spare was abused far beyond its recommended limits, the lawsuit inevitably fails, leaving the luckless motorist to pay the defendant's legal fees.
The final problem I learned about from the dealer was that some (not all) manufacturers may make a given model of vehicle for ten years or more. They'll order spare wheels and tires in bulk from a supplier, hundreds or thousands at a time, but donut spares are not ordered to a specific wheel and/or tire measurement. Instead, the overall dimensions of the spare will be specified. That means a larger wheel diameter with a smaller tire may fit those dimension, or a smaller wheel diameter with a larger tire. The only common factor will be the spacing and size of the holes for the lug nuts. It's up to the supplier to send an order that meets the overall dimensions. The next order, or one from a different supplier, may meet the same overall dimensions, but with different wheel and tire diameters, widths, etc. Therefore, when ordering a replacement donut spare tire, it's essential to note the measurement of one's existing tire and order an exact size match. Otherwise, a tire that may be used by some vehicles of that model might be supplied - but it may not fit your specific vehicle's spare wheel. Tricky!
As you can tell, I learned a lot. The dealer has ordered my new spare tire, and it'll be here within a couple of days. I'm looking forward to being a bit better equipped, for safety's sake.
Peter
I've wondered about getting an extra wheel and mounting a bias ply tire on it, and use that for a spare.
ReplyDeleteMany vehicles won't fit a full size tire anymore; I've tried it on a couple.
DeleteJonathan
My father had me get a full size rim and tire for my first car. He didn't trust the new fangled limited service spares. This was in addition to the premium jack, jackstand and toolkit, including bow saw and axe. There wasn't much room in the trunk afterwards.
ReplyDeleteDecades later, I equip my vehicle the same way. It is better to have and not need, than to need and not have. There are some changes, such as an electric air pump instead of the old bicycle pump, but the concept stands. Call for help? Nah, I got this.
My car has run flat tires -- no spare at all. You could see if run flats are available in your car's size, and not have to worry about the donut spare or even give it a thought. Tires have a code that tells you how old they are, but who would look underneath the car to check on the spare?
ReplyDeleteSpace saving tires are the bane of tire existence. Many vehicles, especially pickups, have full-sized spares, and some get rotated through so get used. My wife’s ‘07 Jeep Liberty has been slightly modified with different wheels and tires…the spare mounted on the rear gate is under cover, it does not get used except for emergencies, which with modern tire technology is rare. I check it every so often but when getting new tires take the best one of the four and replace the spare.
ReplyDeleteWow - that was an educational post. Thank you for all of the information given. I was aware that tire lives expire, but never considered the spare tire that is underneath my truck bed. I make a point of replacing the spare tire when I buy tires with the best of the replaced. Never gave it any thought on how old that tire is though. All of my vehicles are old and i do not have any with the smaller donut.
ReplyDeleteGuilty of the "not checking" part. I bought a GMC diesel pickup about eight years ago. Used. 200k miles. Good price. I needed to get underneath to replace a relay, and part of the process was "remove the spare tire". Not only have I never removed or looked at the spare tire in the past eight years, I didn't even know I was supposed to drop it down and clean/lubricate the mechanism at least once a year. I can't get the thing out from under the truck and may have to cut the hanger and buy a new one. 😒
ReplyDeleteCarrying a plug kit ,some Slime and compressor is a good idea, too. The idiots rotating our tires zip lugnuts on with an impact, then put a torque wrench on, the Nut doesn't turn before it clicks, because it's over-torqued already.
ReplyDeleteAs a broke down geezer I'm not sure I could even change a flat.
Remember, the Donut is small. You don't want it on a Drive axle. The differential will Think it's in a corner. The spider gears aren't designed to be spinning all the time. You can wreck a differential.
So, your front wheel drive gets a front tire flat. Unless you can get to service in just a few minutes, you Need to get a rear wheel off and put That on the front.
Yeah, solve that riddle.
IDK how I'd feel about a coupla cans of Fix-A-Flat in the trunk, or under the floor of my SUV. How hot can they get before they explode?
The RAV 4 has enough room next to the spare for paper towels, a towel, a plug kit and a kit from Slime with sealer and compressor. The sealer hose has a valve stem tool on it.
I live in Arizona where it is 50+ miles of high speed interstate between home and literally anything. I was fortunate and my Hyundai Santa Fe spare mount under the rear has enough room that I bought a full size regular wheel and compatible tire and mounted it there using the same system.
ReplyDeleteI've got an SUV (Ford Explorer) where the spare isn't even on the bottom of the car, it's in the air conditioned cabin, and I still forget to check it regularly. Considering that the I bought the car 14 years ago, and have only doubled the mileage it had in 2012, I should probably replace it.
ReplyDeleteFriend's car has the donut. I bought a full size wheel and tire for her. I don't care about aesthetics when it comes to getting home safely.
ReplyDeleteMy old 1999 Suburban had the original spare in it. I blew out a tire and had to rely on a 24 year old spare. I was a bit clenched until I made the 130 miles back home. I felt like a heel when I replaced it. It sat there for almost a quarter century and performed like a champ when the call came. I should've put it on a pedestal in the shop.
For at least two decades, Ford owner's manuals referred to the temporary spare as a "temporal" spare.
ReplyDeleteI replace donut tires with a real one.
ReplyDeleteYet another data point confirming that people are stupid...
ReplyDeleteBack in 1932 safety rims were required by law. This kept a flat tire from coming off the rim and jamming the steering.
ReplyDeleteTHANK YOU FOR POSTING THIS!!!
ReplyDeleteSo, do you think my donut tire that came with my '95 Saturn is no longer usable? YES, you'd be right - I just checked... I think the last time I used it was maybe 20 years ago, and only once or twice before that, and haven't thought about it since. I needed this reminder.
And, yes, it is essentially flat and most certainly oxidised. Granted I don't drive it much anymore but now I know it needs attention.
I plan to get a replacement for the donut, but I also have an actual spare tire and, assuming I can find/salvage an original rim, plan on getting a full size spare made as well, since I'm a "belt and suspenders" kind of guy.
Thanks again!
The only thing that I hate worse than donut spare tire is the no spare tire with run flats. One of my parent’s cars had the run flats and no spare tire. Was great until they ripped a four inch hole in the side wall of one of their tires. They called AAA and had their vehicle and themselves delivered to my office building for me to fix. They then took an Uber to their destination.
ReplyDeletePeople are stupid. I've seen cars with not one but two donuts mounted at highway speeds. I try to get a full sized spare and add that in, but I will admit I've been a bit lax of late. Have not had a tire failure of any kind for some time. Probably have one now though. Oh well, just another todo to be done.
ReplyDeleteI just realized that the spare on my 1997 F-250 is still the original. I should probably address that.
ReplyDeleteDon't forget that undersized spare tires tend to run at higher pressure than regular tires AND they are stiffer than regular tires so you can't tell by looking if they have enough air in them - whenever you use one you need to check the pressure and be ready to add air.
ReplyDeleteI once lost a donut by not checking - a couple miles down the road I now had two flats and had to wait for a tow.
Jonathan
When I used to drive over 40 miles each way to work, I always went to the junk yard and bought a wheel and tire for the make and model of my car. I did that for around 15 of the 35 years that I worked here in my present city.
ReplyDeleteI was 18 by about 3 months, and even though I worked in a steel melt facility, we didn't make much money until after I had moved closer. So my picking up a new tire for a spare, that I was not going to drive every day was something that I could not afford to do.
My dad drove about the same route for over 40 years, only to a different job. I once mentioned to him that I was considering a 4 wheel drive to make sure that I didn't get stranded in some of the horrible snow storms we used to have here in lower Michigan. He told me that the price of doing that was simply not worth it. If the weather was so bad that I needed 4 wheel drive, I should just call in and not work that day.
Good advice and it got even better the longer I worked. After I got over 25 years, I had 5 weeks of vacation time and could call in and get paid for the day if I was unable to get to work. But I didn't abuse that privilege since my job was always one that was harder to replace with no notice.
After I had been there so long, I could do every job in the place and so was what we called a floater. So one day I might run a furnace and the next I was working on an inspection line.
We've always replaced the doughnut spare with a real tire when we traveled, never had a flat.
ReplyDeleteConcur that they are special use, and for those with run flats, they CANNOT be repaired, so you have to buy a new tire! BTDT... Got rid of them in a hurry, and bought a real spare.
ReplyDeleteIn general Im in the get a full sized spare and have the proper jack and tools to change it camp.. however I'm going to differ a lot in specific.
ReplyDeleteIve gotten old tried to change out the brakes on my van 3 years or so ago... jacking it up, and pulling the tires off just about killed me. Also one lug on the front was literally un-removable and I had words with my tire guy about it afterward. Made him do the brakes for me too, for a drastically reduced price.
My solution is called AAA. I have had a membership for about 20 years. We always drive much older cars. A new car to me is one with only 100,000 miles on it. I think I paid 130 dollars this year to renew.. maybe 140. Still worth it. Between me and wife we use it 1 to 5 times a year. Run out of gas? they will bring some. Battery die and you need it now.. they will bring it and install it free (you still have to pay for battery but when we did it it wasn't marked up to bad.) lock yours self out? they will come and get you back in. Hit the curb and blow a tire, they will come get the vehicle and drop it off at your mechanics. Have a wreck, they will come get you and haul you home or to the mechanics... 100 mile range. It has paid its self back every year I have had it other than a couple years where nothing went wrong.
I still have the stuff for if no one can come get me or help me but my ability to use that stuff is a the point I won't unless there is no other option. I have literally come close to passing out trying to remove a tire in the last few years and had to just concede I am not the man I once was or even thought I was in the last few years. If my life depended on it I could probably still do it over an hour or so. Jack car till weight is still barely on tire. Take a few nuts off and take a break, next nuts, break, next nuts. Jack up the rest of the way. Remove tire and get spare out, at least two breaks there. Put new one on.. at least a couple breaks :)