Spare Tire Questions

[easysurfer]

Believe or not, I have never changed a flat tire on my own (though have helped out and been a witness to a couple ).

My approach is to have good tires from the start and don't let them go bald on me. But I probably shouldn't tempt fate too much.

The videos mostly just say, safety first, have an inflated spare, loosen lug nuts, jack up the car, put on the spare, lower the jack, tighten lug nuts.

Yet, the videos still left some questions unanswered. So here they are:

1) What tire pressure should the on the spare if it's a doughnut spare type? Do I use the PSI on the door sticker? Or is that different for a spare?

2) Should a torque wrench be used when tightening the lug nuts? The videos don't mention about a torque wrench

3) On video said that the spare should go on the back and not the front. If you have a front wheel drive, a doughnut spare can ruin the transmission. Is that true?

[MichaelB]

I'm sure you will get lots of helpful responses on this. Changing tires is very risky due to other drivers not paying attention and hitting you or your car. The first thing I do is get my car as far away from traffic as possible, even if that means ruining the current tire. Then I put the mini-tire on and get a new tire the same day or the next. And yes, loosen the lug nuts before jacking the car.

I've had two punctures in the past 5 years, all good tires (pricey Michelins), so tread doesn't guarantee avoiding this.

[REWahoo]

Quote:

Originally Posted by easysurfer 1) What tire pressure should the on the spare if it's a doughnut spare type? Do I use the PSI on the door sticker? Or is that different for a spare?

Do not use the door sticker pressures for a doughnut spare. It will have the pressure requirements listed on the sidewall and will almost certainly be much higher than the door sticker pressures.

Quote:

Originally Posted by easysurfer 2) Should a torque wrench be used when tightening the lug nuts? The videos don't mention about a torque wrench

Don't worry about using a torque wrench for the spare, just tighten them very firmly. Then stay within the speed limit written on the spare sidewall (50 MPH?) and head to a tire shop to buy a new tire. If you have to travel more than 50 miles before you can remove the spare, stop and re-tighten the lug nuts to be safe.

Quote:

Originally Posted by easysurfer 3) On video said that the spare should go on the back and not the front. If you have a front wheel drive, a doughnut spare can ruin the transmission. Is that true?

That's a new one on me. I doubt driving a few miles on it until you can buy a replacement tire would do any damage.

[pb4uski]

Quote:

Originally Posted by easysurfer ....On video said that the spare should go on the back and not the front. If you have a front wheel drive, a doughnut spare can ruin the transmission. Is that true?

I doubt that. There is no way that carmakers would want a customer with FWD who blows a front tire to change a back tire for the donut and then put the good back tire on the front. If you didn't get the bad tire replaced and drove around on the donut for lots of miles I could see it being a problem, but not for temporary use. I suggest that you check you owner's manual and follow the guidance there rather than an internet video.

I have an AWD which is even more sensitive to tire size than FWD and IIRC my spare is not the same size as my regular tires.

[REWahoo]

easy, I found this info concerning the potential for damage to your car by using a 'space saver' spare (my bold):

Quote:

Long-term use of the spare can cause a serious mechanical issue, too: The smaller-diameter tire can put a lot of stress on your differential. The differential has a tricky job. It transmits engine power to the wheels from the transmission, but it also lets the left and right wheels turn at different speeds. This is essential for cornering. In a turn, the path of the inside wheel is shorter than that of the outside wheel, which means they travel at different speeds. When your car is driving in a straight line, the differential isn't in use and there's little wear and tear on its gears and bearings. But because the spare is smaller than the opposing wheel on the same axle, it must turn faster to keep up with the speed of the car, making the differential work to account for the variation. It's as if the car is constantly in a turn. Leave the spare on long enough and the grease lubricating the differential will begin to break down, accelerating wear between the gears and the clutch plates if it's a limited-slip differential. For all these reasons, manufacturers suggest keeping speeds below 50 mph and using the spare tire only for limited distances if possible.

How Long Can You Really Use the Spare Tire? - Popular Mechanics

[Midpack]

I've changed a tire many times, twice on the side of the road, dozens of times in my garage (snow tires every winter, summer tires every spring for 6 years). It's easier than you think.

Yet, the videos still left some questions unanswered. So here they are:
Videos are fine, but every car I've ever owned had excellent instructions with pictures showing how to change a tire on that model. If you follow them step by step, including exactly where to place the jack, it should take 10 minutes at most.

1) What tire pressure should the on the spare if it's a doughnut spare type? Do I use the PSI on the door sticker? Or is that different for a spare? Spacesaver spares are usually 60 psi, every tire shows a max on the sidewall, included donut spares, just fill to something under that (80-90% of max). Tires are usable short term at almost any reasonable pressure, even 50% of recommended. I check my tires monthly, check spare psi annually (thanks to Outlook reminders).

2) Should a torque wrench be used when tightening the lug nuts? The videos don't mention about a torque wrench. Not necessary, just all good and tight. Just make sure each nut is properly seated before you tighten them all. You or a tire shop can check torque later.

3) On video said that the spare should go on the back and not the front. If you have a front wheel drive, a doughnut spare can ruin the transmission. Is that true?Never heard that, and I'd say it's false. However, the donut spare is meant for temporary use, and not at 70 mph - take it easy. If your spare is (way) underinflated, you should drive much slower (35 mph) and get it properly inflated right away! Obviously if you blow the spare, you're in deeper trouble. Though you see people drive on them for days, I would get the tire repaired and the donut off as soon as possible, normally within 24 hours.

Again, just keep your tires and spare properly inflated and follow the cars manual on how to change. Get the car out of traffic, a parking lot vs side of the road where possible, on a level surface, and keep the jack straight up and down (not leaning).

My best advice for everyone, change a tire at home for practice following the instructions. My Dad made me do it when I was about 12, and I've never been afraid since...anyone who wants to can do it if they're at all physically able. By practicing once, your questions will likely be answered - before you have to do it in the dark, rain, in traffic.

We had a flat on the way to a theater once, I changed the tire in less than 10 minutes and we made the play on time. DW was impressed, 'I didn't know you knew how to do that.'

[painterbill]

1) There should be a pressure on the sidewall of the spare that should be used, absent that then the pressure on the door post will work.
2)A torque wrench is the preferred way to ensure the proper torque is reached and it is even around all lugs. Using a lug wrench though will yield surprising close torque numbers if you use consistent pressure on the end of the wrench, although making sure the numbers are close the required numbers takes practice. You can get by without the torque wrench along side the road but, if able, use the torque wrench when installing the repaired tire. Most will say the use of a torque wrench will help eliminate warped rotors/drums but its is more important to ensure the designed tightness is achieved.
3)Replacing the flat directly with the donut spare is acceptable when going a short distance to get the tire repaired, won't drive hundreds of miles with it. Most differentials will account for the size difference, there are some "locking" differentials that it would create a strain but they are mainly on hard core off road vehicles.

[painterbill]

Wow, people type faster that I do.

[Midpack]

Quote:

Originally Posted by painterbill Wow, people type faster that I do.

Me too, though I blame my iPad "keyboard."

[rbmrtn]

Agree with REWahoos comments. The mini spare is for emergency only to get to a place where you get a new tire correct for the car. The inflation pressure of the spare is stamped on the tire wall. Also you should check the spares pressure periodically, it will lose pressure over time.

You can use a torque wrench, but not required. Just don't over tighten, Wheel Tech - Wheel Lug Torquing

It would be a good idea to do a trial run if you don't do this often. Make sure you know where/how to get to your jack and tire tool and spare. Make sure you can loosen the lug nuts. Many shops damage/break the bolts threads using the impact wrench, put them on so tight they are impossible to break loose. Don't want to find that out in an emergency. I rotate my own and tighten to the specs by hand.

[Nords]

Quote:

Originally Posted by easysurfer 1) What tire pressure should the on the spare if it's a doughnut spare type? Do I use the PSI on the door sticker? Or is that different for a spare?

Use the number stamped on the sidewall of the spare, which is usually something like 60 PSI.

I inflate our 60-PSI spare to 70 PSI and check it twice a year. During that six months it drifts down to ~50 PSI. I'd check it more frequently but I practically have to take apart the entire rear end of the car to accomplish that. It'd be great if spare tires carried the same tire-pressure monitoring system as the other four tires, because usually the spare goes flat in storage before one of the other four goes flat on a nail.

Quote:

Originally Posted by easysurfer 2) Should a torque wrench be used when tightening the lug nuts? The videos don't mention about a torque wrench

It's not worth the effort or your time. The typical car jack wrench is too short to overtorque the lug nuts. If you're worried then you could check the lug nuts again with the wrench after 30-60 minutes of driving. Unless you're built like a MMA fighter, just go slightly less than the max torque you can apply.

Torque wrenches were the bane of my existence in the submarine force. They're expensive, they're easy to knock out of calibration during routine use, and they can give the user a false sense of security-- or even cause them to miss the whole point of the exercise.

Typical conversation with a submarine torque wrench user:
"Hey, Petty Officer Schmuckatelli, this flange is leaking."
"Yessir, but all the nuts are torqued to specifications!"

[ERD50]

Quote:

Originally Posted by pb4uski ... I suggest that you check you owner's manual and follow the guidance there rather than an internet video. ...

Absolutely - some cars may have some unique restrictions. Always best to check the manual.

Quote:

Originally Posted by MichaelB ....Changing tires is very risky due to other drivers not paying attention and hitting you or your car. ...

I'll take that a step further, and say it is very risky period. Especially for people w/o some mechanical background/experience. If you don't have that jack inserted properly, and on solid ground, and the car on solid, level ground, you risk having it slip off the jack. That is all second nature for people familiar with doing this kind of thing, but it really isn't obvious for those who don't. Especially on ths side of the road, maybe in the dark.

A couple times when I've had to do it, the lug nuts were so tight I had to stand/jump on that wrench to get them loosened. That's not something I would expect my wife to be doing on the side of the road. And she might slip, either hurting herself and/or rounding off the lug nut, making it even harder for me to loosen them when I get there.

I've instructed my family to call me or a service if they have a flat. Not worth the risk, IMO.

And I don't mean this to sound condescending, just a helpful observation - it's the kind of thing where if you have to ask these kinds of questions, I would suggest to not DIY. Or, learn with these kinds of questions, read the manual, and as others have suggested, practice under controlled conditions (daylight, a solid, flat driveway, with help).

-ERD50

[Midpack]

Quote:

Originally Posted by ERD50 That's not something I would expect my wife to be doing on the side of the road. And she might slip, either hurting herself and/or rounding off the lug nut, making it even harder for me to loosen them when I get there.

The OP easysurfer is a male, not someone's "wife."

[JakeBrake]

Since I have changed many flats and have had a few blowouts while driving, here are my comments.

1. Torque. My problems with torque have involved the tire store applying too much torque with power tools. I have had lugs broken off by the tire store. When you have a flat with a tire that has been over torqued, the OEM tire tool will sometimes bend or break before it loosens the lug nut. That's the reason I keep quality Craftsman tire tools in my vehicles. As a previous poster noted, it's good to rehearse changing tires in your driveway.

2. Full-size pickup trucks. Full-size pickup trucks have full-size spares, which are conveniently located under the truck. Murphy's Law states that you will get muddy or at least dirty while getting the spare down. Also, full-size pickup tires are very heavy for an old man or a small woman. You might want to call AAA if if you have a flat on your full-size pickup or SUV.

3. Blowouts. I've been fortunate that the blowouts I've had have been on the rear tires and I've been able to stop safely. I've also had a valve stem pop out, which is almost like a blowout.

4. Driving on a small spare. Back in the day. I drove 150 miles to get to my preferred tire store with a small spare on the rear of a front wheel drive car. No harm done. I'm still driving that car several years later and I still have the same spare.

5. Tire pressure indicator. When we travel from the low country where we live to the Colorado high country, the tire pressure warning will activate. I've learned to ignore that. It will do away when we get back to the low country.

[ERD50]

Quote:

Originally Posted by Midpack The OP easysurfer is a male, not someone's "wife."

I understand, I was just broadening the conversation.

And some women are more mechanically inclined than some men. I'm just saying, people should not underestimate the dangers, and someone who is not mechanically inclined may not have a good grasp of the risks.

-ERD50

[grasshopper]

Yes, I have one. I can't fit into my embroidered jeans from the 60's. Oh AAA.

[meierlde]

Quote:

Originally Posted by JakeBrake Since I have changed many flats and have had a few blowouts while driving, here are my comments. 2. Full-size pickup trucks. Full-size pickup trucks have full-size spares, which are conveniently located under the truck. Murphy's Law states that you will get muddy or at least dirty while getting the spare down. Also, full-size pickup tires are very heavy for an old man or a small woman. You might want to call AAA if if you have a flat on your full-size pickup or SUV. .

Also if the mechanism to lower the spare has not been used, it may be overtourqued as well. I had to get AAA out to get the tire out one time.

On another point for $20 you can get a small 12 tire pump to inflate tires as need be and inflate the spare also. (Today many compacts skip the spare and put a tire pump with fix a flat as well instead). Of course these cars also have the telematics systems to call for help.

[GrayHare]

Practice at home under controllable conditions is essential. Recent cars are more sensitive to the placement of the jack: put the jack in the wrong (weak) spot and you'll punch a hole in your floorboard before fully lifting the car. The manual should illustrate acceptable jack locations.

After returning from a shop, I make it a habit to adjust the lug nut tightness. Shops very often turn them too tight to loosen with the tiny wrench supplied with the vehicle. At times I've had to use longer wrenches, and even a strong piece of pipe as a wrench extension. Some cars have tires with special lugnuts that cannot be loosened except via a certain key inserted in the wrench, so be sure you know where that key is (it's usually with the jack).

[infoseeker]

I am female and not mechanically inclined. Not until I was 57 did I need to change a tire on my own. I was fortunate in that I noticed the flat when the car was in our garage. No one around to assist me. (We live in a secluded rural area). My options were do it myself or call a tow truck. It was daytime, nice weather, no obligations that day, so decided a good time to get over my fear of tire changing and do it myself. The hardest part was trying to figure out exactly where the jack needed to be placed....owners manual picture was fairly useless. I did not trust that flimsy jack that came with the car.....so took on the added challenge of using the 1 ton hydraulic jack that we had in our garage. It took me a good 45 min to 1 hour to get this all done, but the feeling of accomplishment was well worth it!

[Sesq]

Just change one yesterday as my wife's new highlander got a puncture. She has never changed one, and she watched. My driveway has a very modest slope. Had a big impact on the jack stability. Flat surfaces will keep your jack flat and prevent your jack tipping and falling out. Like mine did (landed on the tire, no major damage) which was a PITA.

After watching me, my wife concluded she will be calling roadside assistance if its at all practical.