From: xenolith@optusnet.com.au   
      
   On 25/7/2022 2:59 pm, The Real Bev wrote:   
   > On 7/24/22 8:09 PM, Xeno wrote:   
   >> On 25/7/2022 10:59 am, The Real Bev wrote:   
   >>> On 7/24/22 5:45 PM, Paul in Houston TX wrote:   
   >>>> The Real Bev wrote:   
   >>>>> 2013 Corolla S with the original wheels, tires and pressure   
   >>>>> sensors. There are only 33K miles on the tires and the tread is   
   >>>>> just fine.Ever since I've had it (2016) a single tire loses air   
   >>>>> very slowly -- it used to go from 32 (or 35, I'm not real picky)   
   >>>>> down to maybe 24, and the light would come on.  A month or so later   
   >>>>> the same thing happened.  Time between lights is now between one   
   >>>>> and two weeks.   
   >>>>>   
   >>>>> Dealer said he couldn't see a problem.  (I have no actual proof   
   >>>>> that he actually looked.)  I have a nice plug-in tire pump (the $35   
   >>>>> one from Harbor Freight;  the cheaper one burned up rather quickly   
   >>>>> when I tried to pump all four tires) so there's no real problem,   
   >>>>> and I'm unwilling to load the tire up with slime, but I'd really   
   >>>>> like to know WTF is happening.  Sooner or later I'm going to need   
   >>>>> new tires and it would be nice to know if I need a new pressure   
   >>>>> sensor too.   
   >>>>>   
   >>>>> BTW, I really like the tires (Goodyear Eagle RS-A) -- excellent   
   >>>>> cornering on the road I take to go skiing.  People really need to   
   >>>>> be ashamed when they get passed by a granny in a 9-YO Corolla!   
   >>>>   
   >>>> If the manual tire gauge agrees with the pressure sensor then the   
   >>>> pressure sensor is ok.   
   >>>   
   >>> The red light just says I NEED AIR.  The gauge on the pump and on my   
   >>> nifty little talking digital one are never the same -- I've NEVER   
   >>> seen two gauges the same, in fact.  For one reason, you lose a little   
   >>> air each time you check.  I wonder if the sensor device itself has a   
   >>> tiny leak.   
   >>>   
   >>> Some of the tires have plastic caps, some not. I had a cap on this   
   >>> one originally, but I lost it a while back.  No difference.  I keep   
   >>> meaning to buy some of the metal ones with the core tool, but I forget.   
   >>>   
   >>>> You did not say if it is always the Same tire -   
   >>>> will assume so.   
   >>>   
   >>> Yes.  The others hold air for months with or without cap.   
   >>>   
   >>>> Every time I had that problem there has been a nail or screw in the   
   >>>> tread.  The left rear of my Kia had that problem for last two years and   
   >>>> I finally upped the air pressure to 40+ and soaped it.  Found the screw   
   >>>> and removed it with needle nose pliers and then plugged it.   
   >>>   
   >>> I'm sure that if the dealer (amazingly enough, and against everything   
   >>> I knew about buying used cars for the last 50 years, I bought the car   
   >>> from the dealer, and it was the first one I drove when I decided on a   
   >>> 2- or 3-YO Corolla -- I couldn't see a reason to NOT buy this one!)   
   >>> would have found something obvious if he'd bothered to look.  They   
   >>> used to do a free rotation with the discounted oil change, so there's   
   >>> really no reason he shouldn't have given it a visual inspection;  I   
   >>> didn't expect them to take it off the rim.   
   >>>   
   >>>   
   >> A *visual inspection in-situ* will not find a slow leak. All that is   
   >> doing is a scan for the obvious, like a *visible nail*. To do a proper   
   >> inspection for a slow leak, you really need to remove the wheel and do   
   >> an immersion test. A pressure leak that loses ~10psi over a week will   
   >> show as a bubble every now and then during the test. When I was a wee   
   >> apprentice, we had a water vat purely for the purpose of leak testing   
   >> tyres. The practice works.   
   >   
   > Works fine for motorcycle and bicycle tubes. Car tires, not so much.   
   > Easier to just pump the damn thing every couple of weeks.  Know anything   
   > about the effects of Slime on pressure sensors?   
   >   
   >> FWIW, your tyres are getting to the point where I would call them *time   
   >> expired* or, as they say, past their *use by date*.   
   >   
   > So I've been told, but I've never had tires "expire" from anything not   
      
   Cruise down the freeway on a very hot day at 70mph+ and your mileage may   
   vary.   
      
   > involving tread, puncture or -- and this I regard as criminal --   
   > sidewall bubbles in the defective and obsolete tires the Cadillac (or   
   > maybe it was Ford, it was quite a while ago) dealer sold to my mom at a   
   > premium price and refused to replace, turning the problem over to   
   > Bridgestone.  My Ducati's tires held air for at least 20 years in spite   
      
   It's not about holding air.   
      
   > of visible crackling on the sidewalls.  Probably more because I don't   
   > know when the previous owner bought them.   
      
   Visible cracking isn't the issue so much as the depth of the cracking.   
   Signs of cracking, and the tyre lightening in colour, are signs that the   
   tyre is *aging* and losing the chemicals that keep the rubber supple and   
   protected from ozone attack. Tyres that are cracking are showing visible   
   evidence that the rubber is hardening so grip will be negatively affected.   
   >   
   >> I have never had the   
   >> issue of tyres time expired, they are typically worn out in 3 to 5   
   >> years. I'd clock up 33 k miles in 2 years, maximum 3, so I've never seen   
   >> a tyre on any of my cars over 5 years old.   
   >   
   > They don't get much wear at 3K miles/year.   
   >   
   My wife's car does 5k miles per year. It is currently at 30 k miles and   
   is 6 years old. When it reaches 10 years old, the tyres will be replaced   
   as a set *regardless* of how worn the tread is. FWIW, I don't even run   
   tyres down to the minimum *legal* tread depth since I'm not a fan of   
   aqualplaning.   
      
   --   
   Xeno   
      
      
   Nothing astonishes Noddy so much as common sense and plain dealing.   
          (with apologies to Ralph Waldo Emerson)   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)