Checking Spare Tire Pressure

[Gryphon]

I was a good boy today and faithfully checked the tire pressures in my RX400h. But the spare puzzles me. Do I really need to remove the spare tire to check pressure? If so, what a worthless design. I'd rather not have a flat and try to replace it with another flat.

Tom

[mehullica]

You need to lower it from the body to gain access to the tire valve.

[Rx330driver]

...im pretty sure it wont be flat...

I never ever ever check my tire presure, lexus does it for me every 5K miles. but even if i didnt have them doing it, i dont think the spare would be on the checklist. For one, your not using it, its not like much of the air just comes out randomly, maybe only a few psi. Second, how often do you have to use your spare...ive never had a flat tire in my life. third, the flat tire is meant to be a "spare" which means you change it and get to your nearest body shop to buy another tire for replacement. its okay if its not at optimal tire pressure. ;)

[LexRexBlue]

When I bought my first Lexus RX I couldn't believe the salesman wanted to show me where the spare tire was located. I told him I didn't plan on using it! I never did. The car is over 8 years old. Then I bought the RX400h. The car was a week old, I had driven from NJ to Philadelphia. The car was in a hotel garage all the way upstairs. Would you believe the day I was to drive back to NJ the car had a flat? Lexus service came but the man only carried the tools upstairs rather than bringing up the truck. They changed the tire. When I returned home, the dealer repaired the tire. We left it as the spare. It's a year and a half later and I haven't had any more flats.

[larrytrk]

When I bought my first Lexus RX I couldn't believe the salesman wanted to show me where the spare tire was located. I told him I didn't plan on using it! I never did. The car is over 8 years old. Then I bought the RX400h. The car was a week old, I had driven from NJ to Philadelphia. The car was in a hotel garage all the way upstairs. Would you believe the day I was to drive back to NJ the car had a flat? Lexus service came but the man only carried the tools upstairs rather than bringing up the truck. They changed the tire. When I returned home, the dealer repaired the tire. We left it as the spare. It's a year and a half later and I haven't had any more flats.

My 06 is a year old, I just hit a pothole and after the spare was installed, I couldn't open the plastic valve cover cap because of corrosion. The entire valve would spin. Much spray gets thrown on the spare and it's probably a good idea to clean and check it once in a while!!~

[Gryphon]

Thanks for the responses, guys. I normally check my spare tire pressures about twice per year and inflate them to the maximum allowed on the tire. I agree that it's unlikely to have a flat tire, but it has happened to me a few times over the years. I also take my Lexus to rural areas to inspect real estate so don't always expect roadside assistance to be reachable or prompt. I may investigate an extension hose, similar to those truckers use, so I can check the pressure without dropping the tire.

Tom

[Rx330driver]

sure...or just remove the tire and keep it in the backseat, :P

[Gryphon]

sure...or just remove the tire and keep it in the backseat, :P

Surely that practice is confined to RX330 drivers and not hybrids.

Tom

[Rx330driver]

lets not start any RX wars here... <-- dont know exactly what it means to be a pirate, but ive been planning on using it for a while

[Gryphon]

Just teasing, RX330driver.

Nice day.

Tom

[Rx330driver]

lol i know, i was continuing the kidding around. i guess i dont do it as well

[Jim Nazium]

Quick Fix...

My Costco offers to refill my vehicles with nitrogen free of charge, and many of the local garages now have this as well. Give the tire a "fin" and lower the spare tire and refill it with nitrogen. Hopefully down the road if you ever need to use it, the "fat" nitrogen molecules won't bleed through and you will have plenty of air in the spare.

Cheers,

MadloR

[Gryphon]

Jim, I tried the Costco nitrogen thing on two RX400h's and my Porsche 968. All lost about 4 psi over two months. Given the inconvenience of going back to Costco to have them topped off, requiring about a one hour wait, I dumped the nitrogen and refilled them all with good old air. I can once again check and adjust my tired pressures with nothing more than pulling down my air hose from the garage ceiling.

Tom

[Jim Nazium]

Jim, I tried the Costco nitrogen thing on two RX400h's and my Porsche 968. All lost about 4 psi over two months. Given the inconvenience of going back to Costco to have them topped off, requiring about a one hour wait, I dumped the nitrogen and refilled them all with good old air. I can once again check and adjust my tired pressures with nothing more than pulling down my air hose from the garage ceiling.

Tom

Hey Buddy, I hear ya... The real benefit, is if you have expensive wheels. Nitrogen does not have the "moisture", and hence, you will not get oxidation from the inside of the rim. A side note, I did purchase a long time ago a spare air tank. I got them to fill that with nitrogen for me, for that very reason. Yep, I too have a compressor, and for my expensive rims I go to that trouble. For my winter beast, well, I don't really care if I mix regular air with nitrogen.

Cheers,

MadloR

[skyfish400h]

Jim, I tried the Costco nitrogen thing on two RX400h's and my Porsche 968. All lost about 4 psi over two months. Given the inconvenience of going back to Costco to have them topped off, requiring about a one hour wait, I dumped the nitrogen and refilled them all with good old air. I can once again check and adjust my tired pressures with nothing more than pulling down my air hose from the garage ceiling.

Tom

Hey Buddy, I hear ya... The real benefit, is if you have expensive wheels. Nitrogen does not have the "moisture", and hence, you will not get oxidation from the inside of the rim. A side note, I did purchase a long time ago a spare air tank. I got them to fill that with nitrogen for me, for that very reason. Yep, I too have a compressor, and for my expensive rims I go to that trouble. For my winter beast, well, I don't really care if I mix regular air with nitrogen.

Even if costco is offering DRY nitrogen you will still have mosture in the tire unless they PURGE the volume somehow... I can't imagine how they could perform an effective DRY NITROGEN PURGE operation on an automotive tire. You need to have a flow in one end out the other... hard to do on a round thingy.

Besides, the oxidation you are worried about has already occurred on an alloy wheel... it only take a few hours of exposure to the atmosphere for the surface to oxidize. I think you are talking about trying to prevent CORROSION. This is a more detrimental problem than oxidation (which actually helps prevent corrosion because it forms a protective skin).

I would be more worried about corrosion on the OUTSIDE of my wheel than what is covered by the tire.

[Gryphon]

Skyfish, I watch Costco's technique, which involves nothing more than removing the valve stem, letting the air out until it's flat, reinstalling the valve stem, and fillng with nitrogen. No purging at all.

FYI, the Discount Tire's stores in Arizona evaluated nitrogen and rejected it for various reasons, icluding cost and the added work load of customers coming back every time they need nitrogen added (or checked).

Tom

[Jim Nazium]

Jim, I tried the Costco nitrogen thing on two RX400h's and my Porsche 968. All lost about 4 psi over two months. Given the inconvenience of going back to Costco to have them topped off, requiring about a one hour wait, I dumped the nitrogen and refilled them all with good old air. I can once again check and adjust my tired pressures with nothing more than pulling down my air hose from the garage ceiling.

Tom

Hey Buddy, I hear ya... The real benefit, is if you have expensive wheels. Nitrogen does not have the "moisture", and hence, you will not get oxidation from the inside of the rim. A side note, I did purchase a long time ago a spare air tank. I got them to fill that with nitrogen for me, for that very reason. Yep, I too have a compressor, and for my expensive rims I go to that trouble. For my winter beast, well, I don't really care if I mix regular air with nitrogen.

Even if costco is offering DRY nitrogen you will still have mosture in the tire unless they PURGE the volume somehow... I can't imagine how they could perform an effective DRY NITROGEN PURGE operation on an automotive tire. You need to have a flow in one end out the other... hard to do on a round thingy.

Besides, the oxidation you are worried about has already occurred on an alloy wheel... it only take a few hours of exposure to the atmosphere for the surface to oxidize. I think you are talking about trying to prevent CORROSION. This is a more detrimental problem than oxidation (which actually helps prevent corrosion because it forms a protective skin).

I would be more worried about corrosion on the OUTSIDE of my wheel than what is covered by the tire.

I've had a set of rims for about 8 years on my '93 mr2 w/ 3sgte and I was surprised (summer driven only) to find that the amount of corrosion inside the wheel, was the cause of my constant low tire pressures. Outside the wheels were mint, inside they looked like hell.

Anyhoot, if you are a real stickler you could always have Costco (or whoever) fill the tire up completely and then release and refill a second time. Honestly, if you want, you could find fault in anything. But, in a nutshell Nitrogen is superior to conventional air on all levels.

Cheers,

MadloR