How long can I drive on a lightweight spare?
May 12, 2007 9:52 AM   Subscribe

How long can I drive on a temporary (light-weight) spare tire? What are the dangers involved?

Yes, yes. I should only drive on the thing for a max of 50 miles, and only at reduced speeds. But I'm broke and coming up on a payday.

So what's the deal? I understand that the spare will wear out eventually, and that my gas mileage is down, and that I'm putting stress on the other tires.

But other than that? Am i hurting my car? And what's the longest any of you folks have made it on a donut?
posted by es_de_bah to Travel & Transportation (19 answers total)
I'm not mechanically inclined, so I don't know about damage to the car. However, I've had tire people tell me it's bad to have different sized tires. Something about wearing/grinding metal.

Sorry about that, just had to tell you that I have no expertise but I've heard.....

Of course, the main danger that comes to my mind is safety. Seems like you could have a harder time making evasive moves. I wouldn't drive it at night or where wildlife is around, for example.
posted by powpow at 9:58 AM on May 12, 2007

Having recently had a tire blow out on me while on the motorway, I'd strongly recommend spending the money now. It's a scary experience.
posted by MrMustard at 10:13 AM on May 12, 2007

I once made it (slowly) from San Clemente back to L.A. (about 70 miles) on a donut after I had a blowout, which included driving a few miles on the uneven/rough surface that caused the blowout in the first place. By the time I went to the tire place the next day to have it replaced, even I could see that the donut (which, until then, had only been used once before, for a couple of miles) was showing a little damage.

Don't chance it. It's just one tire, and it's not like you have to get one of the top-of-the-line models/brands at the store. Seriously, I think my replacement tire cost less than $50 (I was low on cash at the time too, so it was a relief).
posted by scody at 10:25 AM on May 12, 2007

Do not, I repeat, DO NOT drive on that thing.
On Sept. 23 of last year, I was driving home after putting on that tire. I had put it on less than half an hour previous. On the interstate, It blew out, and my car veered into the wall, spinning. After hitting a light post, knocking it down, and ending 540 degrees from where I started, banging the car on the wall repeatedly, that thing was totaled. The police were shocked that I was able to step out of the car, with only a cut on my toe from hitting the pedal. They had brought a defibrillator!
Just don't do it. The thing could blow out at any time, and a new tire is cheaper than a new car.
posted by The Esteemed Doctor Bunsen Honeydew at 10:25 AM on May 12, 2007

Lots of reasons not to keep driving on it. Another one:
Having 2 different size tires makes the differential work alot harder then it is designed for. Heading for trouble even if you don't blow it out on the interstate.
posted by pointilist at 10:41 AM on May 12, 2007

Two keys to driving on donuts:

1) Check the donut for proper inflation. Many are supposed to run at higher than standard tire pressures (up to 60 psi), and yet stay in the trunk of the vehicles they are supposed to take care of, for years, without ever being checked for proper pressure. Since the donut's carcass is minimal, under-inflation is a more serious problem than it is for a regular tire, and the donut will build heat faster than a regular tire underinflated will.

2) Keep your speed down. Most donuts aren't rated for operation over 50 mph. Your car's handling and load carrying capacity are also limited while running the donut. Respect all those recommendations and limits.

The donut's condition can't really be judged by tread wear, like a normal tire. The life of a donut is much more dependent on sidewall problems than is a normnal tire, and the 50 mile recommendation is based on the idea that the donut will be a lot more likely to sustain damage from road hazards than a standard tire will be. You can't really judge a donut by visual inspection from the outside, so your best bet is not to push it.

Finally, the cost of replacing the donut will add to your tire replacement cost, substantially. You're not gonna throw a donut you've driven over its ratings, already, back in the trunk as your spare, are you? So, you'll be replacing the donut and the tire, and you'll find that a replacement donut costs just about what a tire costs, unless you can get a deal on one at a scrap yard. It'll be cheaper and safer to just buy a tire ASAP.
posted by paulsc at 10:42 AM on May 12, 2007

On the other hand, I once had a regular tire on my Dodge Neon blow out on a highway in Tennessee, at eleven o'clock at night, when I had to be in Lake Charles, Louisana by noon the next day. So I put the spare on the car, and drove it all the way to my destination. That would be well over 600 miles.

So, your mileage may vary -- literally.

(Rest of the story: Spent the weekend in Louisana, bought a new tire on Sunday, and my full pump died on the way home, stranding me Lagrange, Kentucky for a night. That was a damn expensive roadtrip.)
posted by faster than a speeding bulette at 11:27 AM on May 12, 2007

If you have a credit card, you can defer the cost for a month by using it.

Also you can buy used tires for substantially less than a new tire. Resold used tires are usually in pretty good shape, they are generally tires that have been discarded after a few thousand miles when the owner decides to upgrade.
posted by Operation Afterglow at 11:31 AM on May 12, 2007

Is it safe to assume that you can't just pay $5 to patch your real tire?
posted by thejoshu at 11:37 AM on May 12, 2007

what thejoshu said. You, right now, are within walking distance of a place that will fix a tire for less than $15.
posted by Slarty Bartfast at 12:59 PM on May 12, 2007

Discount Tire will patch for free, *but* only if they are satisfied it has adequate tread. If that is out of the question, perhaps you can scrape together enough money for a used tire to get you through to better times?

My condolences, just put new tires on my truck this morning. All Wheel Drive means All New Tires too.
posted by ilsa at 2:40 PM on May 12, 2007

I mean... It's not a good idea to go far, but you already knew that, as you said above. But you asked how far could one go, and though I can't top faster than a speeding bulette's example, I too have been in a car (a full Honda Accord, but not mine) riding on a donut for 200+ miles on highways without any trouble. Had I read this AskMe beforehand, or had it been my own vehicle, I might have insisted on a different course of action, but we made it just fine and to my knowledge, the owner/driver has had no lingering effects once he replaced the tire. Your mileage WILL vary but you asked for personal experiences so there you go. Good luck.
posted by SuperNova at 2:56 PM on May 12, 2007

I drove a tiny K-car on a brand new donut, because I was "too busy" to get the real tire fixed. Nothing in my town is very far, but it only lasted a few days. The culprit was the lateral pressure on the tire in turns. They just aren't meant to take that kind of continued abuse.

Also, I was stupid to be "too busy" since I could have dropped the tire off, then picked it up later. By delaying, I ended stranded in a parking lot, and had to call a friend to rescue me, take me and my tire to the repair place, wait for them to fix it, then drive me back.

Before you have to ask a friend for such a favor, ask a friend for $20 to get the flat fixed, or get a used tire.
posted by The Deej at 4:00 PM on May 12, 2007

We made it from Portland, OR to Seattle on a donut. The I-5 is not the most forgiving highway either. It was Sunday, we needed to get home, and the rim was bent so the Wal-Mart tire center refused to fix it.

If you bent your rim, the fix is closer to $300 so I understand why you'd wait. I'd be nervous in wet weather though.
posted by crazycanuck at 4:02 PM on May 12, 2007

Like most tires, donuts are usually good for far more than the manufacturer claims. They're especially stingy about their claims on the donuts, though, because they're especially dangerous. You should not drive on one for longer than it takes to get to a tire shop and get the old one fixed or a new one purchased.

That said, I once had to drive 120 miles on a donut to get a replacement tire, since it was not possible to get the tire I required any closer, and I couldn't get anyone else to provide me with a ride. Of course, I drove no more than 50 miles an hour the entire time and made sure that it was properly inflated beforehand.

If you are driving on a donut on a front wheel drive vehicle, put it on the back, otherwise you will cause considerable wear to the CV joints. Also, you will likely have an easier time controlling the car should it fail.

As someone mentioned upthread, donuts are far more susceptible to heat generated by traveling over the tire's rated speed, so whatever you do, don't drive faster than its rated speed. I suspect the esteemed doctor was traveling significantly faster than 50 mph, given the description of the crash.
posted by wierdo at 5:33 PM on May 12, 2007

Significantly? No.
Faster? For sure.
posted by The Esteemed Doctor Bunsen Honeydew at 10:44 PM on May 12, 2007

Can we put this in the "spenditnowfilter?" what do you do if you blow your spare?

Fix it. Now. It really is your Life.

And get triple A. Now.

Jus' sayin.'
posted by metasav at 1:02 AM on May 13, 2007

At one point I bought a used tire for $ 5 at an independent tire shop. It lasted me quite a while.

I once bought a full size spare (tire & rim) at a junkyard to replace my compact spare, for $ 35. Lots of cars will have room for a full size spare in the spare tire compartment, even if they come with a compact one. It is much nicer to have when you do need the tire.
posted by yohko at 10:20 AM on May 14, 2007

Thanks folks. Your tips got me to and from work Saturday night and your concern has prompted me to replace the tire without further delay now that I've got the scratch.
posted by es_de_bah at 11:17 AM on May 14, 2007

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