Maintaining proper pressure in the fifth tire

Since you should routinely (twice a year) check the status of vehicle hidden areas anyway, which means taking out the spare tire, this is really a non-issue.

Inspecting seals is a good habit to get into. Discovering a tiny water leak a year or two after it began is not, but a lot of people do... usually when something starts to smell.

Be very thankful the spare-tire is stored inside the car. Thanksgiving 2 years ago was horrible. My uncle discovered had a flat early in the evening. The dark and cold set in before he finally gave up trying to get the spare free from its cradle hanging on the underside of the minivan. It has rusted in place, stuck so bad it later has to be broken off. How much PSI do you think was still in that tire?

 

doesnt the spare already have air in it??

i know that the door on my car says it should have 60 PSI in it...

 

Yes, it will have air in it from the factory. However, it's normal for a tire to gradually lose pressure over time, even just sitting there unused. For that reason, you want to check it periodically to insure that it's still at the recommended pressure, especially after it's been sitting in that well, aging for a few years.

 

Why is it that the pressure on a spare has to be so much higher than that on a regular? Just curious.

 

The extra PSI is to compensate for the design shortcomings of the tire (too thin, not reinforced). As a result, it is clearly not intended for anything but temporary use.

I personally don't think it is that much trouble to reach, since I am one of the few 2004 owners that has actually used the spare for real. I even jacked up the car to remove the damaged regular tire using the silly little scissor-jack. It worked surprisingly well.

 

previously in another car i had, i had a mini spare that was at some high PSI and the instructions said to deflate the tire to like 45 PSI from some higher figure. i always thought that this was done to take into account any pressure loss from extended storage.

of course it also said not to exceed 45 mph or drive more than 50 miles on the thing.

 

I've had that experience, although no problem with the pressure (I checked at the first garage on the way to the tyre shop). After that, I learnt to inspect and if necessary grease the threads of the tyre cradle once or twice a year. The plus side to having the spare tyre underneath the vehicle is that you don't need to unload all your luggage onto the motorway hard shoulder (or worse) in the rain before you can start fixing the car. And I think it's a little more space-efficient (but that's perhaps just me missing a full-size boot).

 

that is a good point about not having to unload if using an undercar spare. never thought about that.

 

I did, and it's not something I like about the car, however having the spare in a cradle underneath the car has it disadvantages as well. As John has pointed out. Dilemma's, dilemma's...

My current car has a cradle thingy, but in order to get the tyre out, you have to turn some sort of screw inside the boot, 'best' of both worlds I guess (not). :mrgreen: :|

 

Raise the pressure in the spare very high while it's stored. This will prevent leakage. Just remember to lower it before you use it!

Also, don't run the spare on the front. If you get a flat on the front, take one of the tires off of the rear and put the spare on the back. Save your transmission!

Nate

 

I have a reply to some of your concerns on flats. If you get frequent flats try checking for the tires that can self seal. I think bridgstone makes some. Or you can check into runflats. I have looked into the runflats and found that you will need to plus size on the rim to find a tire to fit (so replace the rim with new ones one inch bigger in diameter and new tires that will be wider across) This will affect the gas milage of your veh. But it does offer peace of mind when on a dark and deserted road.

 

The air compressor that you recommend- are we talking battery or plug into the cigarette lighter (like) power?

 

I just picked up the Cambell 12Volt air compresser that plugs into the cig litter outlet and it seems to work great but I have a ? about using it.
I know the car must be on or in aux.
so I powered up and turned off the air and just the radio was running (cause I haven't found the off switch yet and I like to normally leave music on).
anyway, it didn't take me that long to go around and add a little to each tire, about a min or two is all it took. I like that you can set the gauge to what pressure you want and it auto. shuts off when it reaches that pressure. it also has a safety light and is good for travel as well as in the garage and it only cost $20 at wal-mart.
O.K. NOW MY ? for you tech. wiz guys, if I take my
time and fill up some tires and maybe an air mattress do I run any risk of draining the 12v battery? Is it necessary to run the car for a bit immediately afterwards to recharge? or are we talking hours before that would happen?
I think but I'm not sure, that the way I was doing it (only powered up once and turned off air) the engine would auto. kick in if the battery was getting low, but I'm kind of clueless on these things and don't want to do anything wrong.
someone recommended the cambell $40 model that plugs in to reg. power which I considered when at the store, but this loooked handier for away from home as well as in the garage, even though it might be a little slower if you need a lot of air.

 

Thanks. Our electric one is wearing out (old Black and Decker), so I was on the lookout for something new, and figured getting a portable compressor for the Prius, was good timing.

 

Hmm, I guess I better check the spare in the Odyssey, I've never even unzipped the cover (it sits vertically in the right rear corner) and the van is over 9 years old! See what you can learn from PriusChat, even if it isn't about a Prius! Thanks all.