Compact Spare Tire Air Pressure

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What do you guys have yours set at? Mine says a maximum of 60 PSI, but 35 PSI gets it pretty hard.

I measured mine at 36 PSI today and brought it up to 40 PSI. Is that ok?
 
Can a full-size spare fit in your trunk?
smile.gif
 
Squeezing a tire by hand isn't very scientific, and doesn't explain the results for a tire's load carrying capacity.
 
Originally Posted By: slacktide_bitog
Can a full-size spare fit in your trunk?
smile.gif



Oh yeah but then I wouldn't have much space for anything else like grocery bags.
 
I set it to whatever the door sticker says. When I worked at Sears Auto people would get so mad at me when they saw me opening their trunk on a tire rotation. I would always set spare tire pressure and almost every one was substantially lower than not only the door psi, but were usually under 20psi.
 
Originally Posted By: Miller88
I usually go 5 or 10 above. Just so there's wiggle room should I forget to check.


Particularly if I do it in the summer...
 
My VW GTI is a bit rare because it came with a full size V speed rated spare from the factory. I set mine to 38 and check it once a month. Super easy to check. It's not upside down and there is a holder to keep the trunk mat up out of your way.
 
Originally Posted By: das_peikko
I'm worried about taking it all the way to 60 PSI because the original factory spare exploded and blew apart.


Yeah, I hear ya. But the tire really does need 60 psi to handle the load.

I'm not sure this would work, but it might be possible to fill the tire to - say - 40 psi, then when you need the tire fully inflated, use a can of sealant to take it the rest of the way. If I get some time, I might try that as an experiment.

And I think the reason the old tire exploded was because it was old and the rubber had deteriorated - putting to rest those folks who think unused, but old tires don't fail just due to age.
 
The tire was designed to be inflated to 60psi. I have seen such tires fail, but always very old ones, they deteriorate over time just like normal road tires.
Keeping it at a lower pressure then inflating it when it is needed seems crazy to me, what if your SO has a flat and doesn't know the spare is underinflated?. Also you will need to carry a pump in the car, partially negating the point of a compact spare in the first place.

Claud.
 
I check mine about twice a year. Since it mounts valve stem down in the well it has to be removed completely from the car. It's usually down to around 40 PSI when I check it. Since most people probably never check theirs I don't know how they expect to have a viable spare in the even of need.
 
Originally Posted By: DBMaster
I check mine about twice a year. Since it mounts valve stem down in the well it has to be removed completely from the car. It's usually down to around 40 PSI when I check it. Since most people probably never check theirs I don't know how they expect to have a viable spare in the even of need.


Some of my family member’s old spares were so low they didn’t register on my gages - essentially flat. Others were lower than 30#, IIRC.

I typically stay further away from an older tire while pressurizing, juuuuust in case. Never had one pop on me going to 60#.
 
Originally Posted By: das_peikko
Originally Posted By: slacktide_bitog
Can a full-size spare fit in your trunk?
smile.gif



Oh yeah but then I wouldn't have much space for anything else like grocery bags.


What kind of car is this?
crazy2.gif


Most spare tire wells will accommodate a full-size spare, even when the car came from the factory with a donut.
 
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