CHECK YOUR TIRE PRESSURE!

When I was in Florida at the beginning of this month I had a 2012 Kia Rio as a rental car and it is equipped with a tire pressure monitoring system. At one point the low tire pressure light came on the dash, although this system didn't say which tire it was. I ended up stopping at a gas station and using the air pump with those crude built in pressure gauges and it looked like all four tires were the same pressure, but all were under 30 psi so I added about 5 or 6 to each one. That day was pretty cold for Florida, only about 50 degrees, so I guess the last time the rental company checked and set all the pressures it was probably at least 20 degrees warmer outside.
 
I'm surprised how sensitive these TPMS can be, speaking of temperature swings. My car is stored in a garage at 10 C. That's the temperature, of course, that I fill and check the tires, then.

We got a massive cold snap a couple weeks back, and the TMPS kicked in after the vehicle had been allowed to cool to ambient, even though the pressure was fine in the garage. I had to give a cushion of a couple PSI, and the light went out.
 
Typically I check my tires once a month. However, when it gets below freezing during the winter I check twice a month. I also usually keep my tires overinflated by 2 PSI. It's amazing how much air the tires can lose when it is consistently below freezing.
 
Originally Posted By: HerrStig
Rim corrosion on alloy rims can sneak up on you with very slow leaks.

Going to do a bump here ...

But I hate alloy wheels. Living in NYS I've come to hate them for a few reason - they corrode to the hub of the vehicle and when they get old they seem to warp constantly. My old car had alloy wheels, when it got around 8 years old, I was constantly replacing wheels. Granted, I would replace warped alloy wheels with junkyard wheels and those would only last maybe a year or less.

My Cherokee came with a set of A/T tires on 15'' Alloy wheels (I have a set of mud tires on 16'' steel wheels for everyday driving and off road). Sitting in my living room, one of them always goes flat. Nothing wrong with the tire, just a corroded wheel leaking air. Hate alloy wheels. I have a set of steel wheels I need to get repainted and mounted.

I have a bit of a weird method. I use a power inverter and a small compressor with tank, but it works well.
 
I follow the old school method in maintaining tires: I inflate them to the maximum cold pressure posted on the tire sidewall. When the tire warms up during driving, the tire runs cooler when it's inflated to its maximum pressure. You're less likely to have the casing separate from the tire if you keep them inflated and running cooler. I have noticed more tire treads on freeways over the past 10 years. Also, whenever you buy new tires, be aware of what country the tire is manufactured in. Some of them are made in China, and are prone to having the casing (treads) separate when underinflated. Even when they're inflated to what the vehicle manufacturer recommends, they separate more often. If your vehicle has a TPMS and it turns on, it means your tires are underinflated to a very dangerous level, or that one of your tires has a leak. I had a screw in one of my tires once, and that triggered the TPMS on my Honda Fit.
 
I check them about every two weeks on the BMW. That is how long it takes for the left rear tire to drop from 36 to 30psi which will trigger the TPMS warning. It is a bad tire that has leaked since it was put on. We had it moved to a different rim and the leak followed the tire, but our local tire shop cannot find a leak - I assume it has to be rolling under load to leak. The other 3 Conti's lose a little air and need to be added to every couple months - they will lose 6 psi in that time. It could be the wheels or TPMS seals, etc., but we need to keep an eye on them.

The FX has a digital readout for each tire on the dash, it has Yokohama Parada-X 's, they lose very little. I typically have to add air when the temperature drops, then they will stay in range for the rest of the year.

On my G35 I have to add air when it gets cold and let air out when it gets hot. They typically do not lose any air. That was with Goodyear F1 GS-D3's, Michelin PS2's and Michelin Pilot SS's. With the Continental DW's I had to add air about once a month, which seemed totally reasonable. I check them about once a month or before I abuse them.

What is interesting is watching how much tire pressure drops when you are on the highway and go into a rainstorm that drops the temperature from 90 to 70 degrees. In the FX it is not uncommon to see a 4 psi drop with the cold wet. I assume tire temp drops much more significantly with the water cooling them, I also imagine the asphalt temp drops from over 140 degrees to about 90.
 
Originally Posted By: mystere
I follow the old school method in maintaining tires: I inflate them to the maximum cold pressure posted on the tire sidewall.


That's not old school...that's just wrong...

That pressure is predicated on the tire's max load rating...and has nothing to do with what pressure your application requires...there have been so many threads on this, I won't bother to repeat, but I would encourage you to do a little research and updating to your approach...
 
I find it excessive to check the pressure once a month unless there is a problem. The pressure in my tires doesn't change much even after 3 month. So usually I check the pressure every season to adjust it according to the ambient temperature. I set up the pressure in a specific way: rear tires - 2.0 bar as recommended but I inflate the front tires to the pressure I find the most comfortable and safe but not less that the recommended. Currently it is 2.4 bar which is not far from the recommended 2.2 bar. 2.5 bar makes the car to oversteer a bit.
 
Now that I have a plug-in inflator from Sears, I do it about once a month and before a road trip, and on the rare occasion that the temperature drops around here.

Since the spare is a little hard to get to -- it's under the floor of the trunk, and I have to unpack everything to get to it -- I check it about every six months, or before a road trip.
 
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