[Pikapolonica]

Got new tires fitted at Bridgestone and driving home, I thought I'd check the pressure.  Readings as per picture.

Today on the way to work, pressure in top left, right and bottom right were 44, bottom left was 39.

Surely they'd know to inflate the tires to the correct pressures?!!?

Do I deflate them to the recommend pressure?  I got Turanza Serenity Plus.

TIA.

[pidim]

Yeah, I would.  Bridgestone always do this to keep their 80,000km promise on Serenity Plus and ensure you don't wear them out too soon.  The guys fitting the tyres don't even look at the PSI, they just wing it based on gut feel.

[TerryT]

Vanessa.  Tyre specialist shops do know how to inflate tyres correctly but some just don’t(!) and they should be called out for it as you have done here.  They got the front, right tyre about right, imo, but the other three tyres were horribly wrong.

Yes, you should deflate the tyres to the correct pressure.  Personally, I would wait until the tyres are “cold” (even better, wait overnight) and then deflate them to the pressures recommended by Hyundai on the plate affixed to the driver’s side door sill.  While Hyundai’s recommended pressures are not perfect in the eyes of many they are, imo, close enough until you work out what pressures are good for your own driving conditions.

A common belief is that car manufacturers set the recommended pressures a little high for ‘longer’ tyre life (= slightly harsher ride) over softer, tyre ‘performance’ grip.  Others believe they set the pressures a little low to cushion the ride for the comfort factor but at the cost of tyre life).  Take your pick. 😊

BUT, I just cannot make sense of your car’s tyre pressures from Day 1 to Day 2.  In looking at them I made two [reasonable] assumptions:

1. The tyres fitted at Bridgestone’s would have been ‘cold’ tyres and the tyres you left home on the next day would have started off as ‘cold’ tyres.

2. The tyres were subjected to similar driving conditions on both days e.g. a leisurely drive from Bridgestone’s and a leisurely drive to work (as opposed to say, a day on a race track, flat chat…but even that would not fully explain the anomalies).

The rear tyre pressures, though badly set by Bridgestone’s, are at least the same on both days whereas the front tyres have inexplicably and radically changed pressures from Day 1 to Day 2, especially the front, right tyre.  Why?  That, imo, would have nothing to do with Bridgestone’s.

Vanessa, the tyre pressure screen at Fig 1 (below) presumably has to be correct but are you sure you correctly reported the tyre pressures that you posted at Fig.2?  I cannot see how the front tyres would increase the next day on their own by 5 psi (F, L) and 8psi (F, R) while the rear pressures stayed the same on both days.  Just don’t think it’s possible. 

Please note, I wouldn’t worry about just a couple of psi difference over a two-day comparison but this…?.


Fig. 1. Tyre pressure after Bridgestone's



Fig. 2. Tyre pressures the next day



Tyre pressure recommendations, my car

[Surferdude]

I agree with Terry that most tyre shops know how to inflate tyres correctly.
Not sure about his claim that car manufacturers set the pressures higher for longer tyre life.

In my experience they always go with a lower pressure for smoother ride.
Car manufacturers don't care at all about tyre life.
They only want to to feel comfortable in your car.

Tyre manufacturers however, care about tyre life because at the end of the day, most drivers judge on that.

I ran my i30 at 40 psi all round. I do the same with my and my wife's Corollas.
38 would be good for your car. If it seems a little harsh (and it may not), within a few days you won't notice it.

But I am concerned about the varied pressures in your pic.

As Terry says, check them after they've sat overnight. And again after they've warmed up. Don't worry what pressure they are at hot. But make sure they're all the same. That should ensure you don't have any small leaks.

[TerryT]

I agree with Terry that most tyre shops know how to inflate tyres correctly.
Not sure about his claim that car manufacturers set the pressures higher for longer tyre life.

C'mon SurferBoy ( ), it wasn't my claim, I was just repeating what others believe (although I was wrong in saying it was a "common belief").  

Some people believe it because they think that the interests of the car manufacturer and the interests of the tyre manufacturer are aligned.  Not so, usually.

I'm like you, I run my tyre pressures higher than what Hyundai recommend on the placard but not quite as high as you.  I set my tyres at 36~37 psi COLD which is 3~4 psi above the placard.

[Surferdude]

You wrote it. Your claim. 

Seriously though.
In all my years in the tyre industry I never heard that said.

Logic suggests the vehicle manufacturers and tyre manufacturers are going to have differing views on what is important in a tyre.

[TerryT]

Seriously though. In all my years in the tyre industry I never heard that said.

But you didn't grow up around the intellligentsia that I did.

Or, maybe I just dreamed it. 

[Shambles]

... what is important in a tyre ...

Air

[Pikapolonica]

I'll take another note tonight when I leave work, when they are cold and when I get home (an hour drive).

[Surferdude]

... what is important in a tyre ...

Air

Watch this space.

Airless tyres could be a reality this decade - Drive

[TerryT]

I'll take another note tonight when I leave work, when they are cold and when I get home (an hour drive).

Ok, thanks Vanessa, that may help answer some questions. 

Have you adjusted the tyre pressures since your post or are the tyre pressures as inflated by Bridgestone's (which means the test parameters are the same i.e. we are comparing "Bridgestone's pressures" on Days 1, 2 and 3? because it was the Day 1 and Day 2 comparisons that confused me).

I only ask because if you have adjusted the pressures, we should know what they are.  And, from a Nanny's-point-of-view it would be a bit safer if you were not running around on 44 psi tyres, especially if it rains.

[Pikapolonica]

No, haven't adjusted anything as wanted to see some suggestions first.

[Pikapolonica]

Pic with 623 DTE was after two minutes driving.

Pic with 567 DTE was after one hour of driving.

[Surferdude]

That LR is interesting. Only up 1psi.
All the others have gone up 3psi

Time to set them at something and see how they go.

I'd still suggest 38 all round. But Terry's suggestion is fine too.

[TerryT]

Vanessa, thanks for the two photos.  Making sense of your tyre pressures over the three days was a bit hard for this ol’ brain…and when alcohol didn’t help, I just gave up and focused on today’s ‘Day 3’ pressures.

Two minutes driving while not strictly “cold” tyres is good enough for me, providing there was not lots of high speed and/or heavy braking involved.  One hour driving qualifies as “hot” tyres for me.

As Surferdude commented, from "hot" to "cold’, your left front, right front and right rear pressures are shown on the dash display as each having increased by 3 psi while your left rear tyre increased by only 1 psi.  Given that these are four brand new, newly fitted tyres, it is possible that the left rear tyre has a slight leak (maybe, at the tyre valve, or a poor seal on the wheel bead, or a crap fitment job?).

While a 1 psi vs 3 psi difference on the dash display does not look good, the display pressures do not show tenths of a psi.  It is possible that the left rear “cold” pressure was 35.0 psi and the “hot” pressure was 36.9 psi!  A 1.9 psi (say, 2 psi) difference, so not as bad.  But then, the same could be said for the other three tyres so the left rear tyre could still be the bad boy of the bunch.

As for tyre pressure recommendations?  I mentioned I usually set my tyres at 36-37 psi COLD (about 3-4 psi above Hyundai’s recommendations).  Surferdude sets his pressure at 40 psi COLD (and he’s the forum’s tyre guru) and he has suggested you start at 38 psi COLD.  So, I would start at 38 psi.

[Pikapolonica]

LR barely changed after two hours diving today.  That’s two minutes was just in thr work car park.

[TerryT]

LR barely changed after two hours diving today.  That’s two minutes was just in the work car park.

Ok, thanks Vanessa, so the left right tyre was officially "cold".   I suggest you now set your four tyres to a proper pressure.  If you have not got a tyre pressure gauge, I suggest you buy a reasonable quality one which you can use to check pressures after inflating at a petrol station.  Also I suggest you buy a tyre valve tool, they are not dear.

You said the LR barely changed after two hours diving today so I see that tyre as needing some attention.

Possible causes of the problem
1.  Faulty TPMS sensor.  It could have been damaged by the Bridgestone technician when he was either removing the old tyre or when he was fitting the new tyre. 
2.  Loose valve core.  Maybe the core in your TPMS sensor was already a titch loose (un-noticed as your air loss is minimal and regular pump-ups on your old tyres could have masked the problem) and the technician didn't check the core's tightness.
3.  Damaged valve core.  When the technician added air, he may have been too rough with the air pump connection and damaged the core.
4.  Air leak at the valve stem base where it fits in the wheel.
 5. Air leak somewhere where the tyre bead fits into the wheel rim.

Solutions to the Possibles listed above, in the same order
1:  A new TPMS sensor, but I'm not sure how you would know at home if the sensor is bad?  Maybe Surferdude has some ideas?
2 & 3.  Quick method:  Spit on your finger, wipe the spit over the top of the tyre valve stem and see if any bubbles form.  Don’t spit into the valve stem.  When finished testing, blow hard into the valve stem (or air-gun it) to remove any spit before fitting the plastic valve cap.
           Slower method: Prepare a solution of soapy water (or water with a dab of dish washing liquid) and proceed as above.
-  If the spit shows bubbles, air is leaking past the valve core meaning either the core is not in tight enough or is damaged. 
-  Use a tyre valve tool to gently check the tightness of the valve core.  See if you can slightly tighten it any further, using gentle pressure. 
-  If the valve core is tight, that suggests the core is damaged and should to be replaced with a new one.  Removing the core (with a tyre valve tool) will cause the tyre to deflate so you will need to inflate the tyre after fitting a new core.
4.  Squirt some soapy water (or water with dab of dish washing liquid) around the base of the tyre stem and look for bubbles.
5.  Use a brush soaked with soapy water (or water with dab of dish washing liquid) and paint around the tyre where the tyre meets the wheel rim, looking for bubbles.

Problem is, your leak seems to be so small it may not easily show up in these tests.

Vanessa, I hope this information is useful for you.  It makes it a bit difficult to post replies to people when you don't know their level of knowledge or experience in these things.  Sometimes you unintentionally wind up teaching someone how to suck eggs. 

Terry
_______________________________________
 
Showing below a more elegant testing method for ladies who don’t like to spit on themselves.   Use a spray bottle with soapy water (or water with a dab of dish washing liquid).  Probably a bit of overkill for the likes of us.   (Doubt your leak would provide this amount of bubbles).


 



Solution #4


Solution #5


Tyre valve tool


Tyre valve tool

[Surferdude]

"1:  A new TPMS sensor, but I'm not sure how you would know at home if the sensor is bad?  Maybe Surferdude has some ideas?"

Sorry. Most of the TPMS technology is after my time.
As I was setting myself up for more surfing time, the only cars with that sort of thing were a few hi perf US machines like Camaros.
And the BMW Mini had only recently hit the market.

I understand there are a variety of systems now with sensors which work on different rolling diameter of tyres which change with pressure, as well as in different types of in rim sensors.
I don't even know where the sensors are on Hyundai. 😱.

If the sensor isn't part of the valve body, I would hope they replaced all of them (the valves) while replacing the tyres. If it is, then it would be normal procedure for the fiter to use the "spit" method to check for leaks before fitting the valve cap after refitting the valve core and pumping the tyre up.

I may have said before, I'm not a fan of TPMS. The cost of replacement is just one more unnecessary expense added to modern cars. But I understand it's getting harder to find a model without them. 

[TerryT]

@ Surferdude.  Thanks for your input.  I appreciate that surfing time prevails over TMPS's. 

I must admit I'm a bit more of a fan of TPMS now that I have a car fitted with it.  But I don't like that the limited life of their non-replaceable battery makes them a consumable; they cost $$$'s for a garage to supply and fit (and often you do four if the sensor batteries are near their end-of-life at tyre replacement time); and it's something else on the car that can break/malfunction etc. 

On the good side: After getting my i30 I was driving home from Lithgow at a smart pace through the twisty mountain bits and felt my car was getting 'squirrely'.   I immediately suspected low tyre pressure/s.  Two-three quick presses of the steering wheel menu button and the TPMS dash display appeared...and showed all the pressures were good.  Confidence inspiring.  So, it wasn't a dodgy tyre, just a dodgy driver who couldn't nail an apex that night to save his life.

[TerryT]

@ Vanessa, in my last post to you (above) I said: "..., so the left right tyre was officially "cold".  D'oh!!  Brain fog.  I meant, of course, the left rear . 

(Not that the typo matters much but needed to correct it because I'm a senior, Virgo...and that's what we do).

[BrendanP]

Last time I had 4 tyres fitted at a well known chain in UK, the tyre pressures were all high because the manager had told the fitter to keep putting air in until the TPMS light went out. Clearly, he was oblivious to the need to drive the car for a while at the correct pressure for the TPMS sensors to 'learn' what the correct pressure should be. The other thing to watch out for if you have a slow leak is whether it's leaking around the bead. This would show up using soapy water but to do it properly the wheel should be taken off and laid flat so the water settles around the rim.

A friend had this problem and it turned out the tyre fitters had applied too much pressure on the machine that grips the rims when putting the tyre on. The rims were no longer perfectly circular, but slightly flattened where the rim was clamped, so the tyre bead didn't sit in it properly allowing air to slowly fizzle out.

[Surferdude]

Last time I had 4 tyres fitted at a well known chain in UK, the tyre pressures were all high because the manager had told the fitter to keep putting air in until the TPMS light went out. Clearly, he was oblivious to the need to drive the car for a while at the correct pressure for the TPMS sensors to 'learn' what the correct pressure should be. The other thing to watch out for if you have a slow leak is whether it's leaking around the bead. This would show up using soapy water but to do it properly the wheel should be taken off and laid flat so the water settles around the rim.

A friend had this problem and it turned out the tyre fitters had applied too much pressure on the machine that grips the rims when putting the tyre on. The rims were no longer perfectly circular, but slightly flattened where the rim was clamped, so the tyre bead didn't sit in it properly allowing air to slowly fizzle out.

As the air pressure which drives a tyre fitting machine is fixed, this wouldn't be a tyre fitters problem.
More related to the machinery.
Whilst I've seen an alloy wheel scratched or gouged by the lever used to guide the bead over the rim, I've never seen a rim actually distorted.

The clamps used are on the back (inside) of the rim and hold it against a flat surface.

[Pikapolonica]

IF Bridgestone damaged the sensors, where do I stand?

[Surferdude]

OK.
Vanessa, before I get into that, I want to thank you for opening this topic. Whilst I realise it's a concern for you, I've actually enjoyed the discussion and analysis.  And it's prompted me to begin updating my knowledge about tpms.

Now, firstly I don't think the sensor(s) are damaged. We can revisit that after we see how the pressures go when reset for a few days.

If there was damage I guess it depends on how the Bridgestone manager reacts. Some would elect to rectify it. Others might deny any wrong doing (or, suggest the sensor was already faulty).
These are franchises so if you aren't satisfied you can complain to Bridgestone Australia who is the franchisor.
They might decide to offer something as a gesture of goodwill.

[BrendanP]

Last time I had 4 tyres fitted at a well known chain in UK, the tyre pressures were all high because the manager had told the fitter to keep putting air in until the TPMS light went out. Clearly, he was oblivious to the need to drive the car for a while at the correct pressure for the TPMS sensors to 'learn' what the correct pressure should be. The other thing to watch out for if you have a slow leak is whether it's leaking around the bead. This would show up using soapy water but to do it properly the wheel should be taken off and laid flat so the water settles around the rim.

A friend had this problem and it turned out the tyre fitters had applied too much pressure on the machine that grips the rims when putting the tyre on. The rims were no longer perfectly circular, but slightly flattened where the rim was clamped, so the tyre bead didn't sit in it properly allowing air to slowly fizzle out.

As the air pressure which drives a tyre fitting machine is fixed, this wouldn't be a tyre fitters problem.
More related to the machinery.
Whilst I've seen an alloy wheel scratched or gouged by the lever used to guide the bead over the rim, I've never seen a rim actually distorted.

The clamps used are on the back (inside) of the rim and hold it against a flat surface.

I found it hard to believe, but when I laid the wheel flat and poured soapy water around it, bubbles were fizzing out in 4 places, spaced 90 degrees apart. A closer look showed the rim flattened slightly at those points. This was on both front wheels. Fortunately I managed to find a set of 4 identical rims on ebay pretty cheap

[TerryT]

Vanessa, I agree with Surferdude.  While I don't think the problem is a damaged TPMS sensor which is reading the tyre pressure incorrectly or causing a leak (by the sensor being damaged when pushed through the wheel's valve hole, affecting the seal) it is possible. 

One way to test the TPMS sensor is to measure the LR tyre pressure (with a quality tyre pressure gauge) then activate the car's TPMS dash display and see what the dash display says.  If your tyre gauge and your dash display are about the same, it indicates the TPMS sensor is ok. 

IMO, to 'prove' that Bridgestone's are at fault in some way you need proof that the car came into their workshop 100% ok.  That's a bit hard to do now but, as Surferdude suggested, the company may look into the problem and fix whatever as a gesture of goodwill.

More importantly:
1.  Have you already adjusted your tyres to a uniform pressure e.g. 38 psi COLD all around?; and

2.  Have you already tried any of the possible solutions I listed in my lengthy post to you on 7 April?  Especially the 'spit' test (Solution #2), which is quick and can tell a lot?  (I'm presuming you haven't done it, because you haven't posted back?).

Terry

[TerryT]

Vanessa.  Here is some more info which may help explain the TPMS sensor setup before you talk to Bridgestones if you decide to front them. 

If your TPMS sensor is similar to mine (and many others) it is likely that the technician did not have to remove the sensor, he just left it in situ on the wheel when your old tyre was stripped off and a new tyre fitted.  But it is possible that the valve stem could have been mishandled at some point, allowing a tiny leak where the valve stem is sealed in the wheel's valve hole.  Maybe unlikely, but still possible.

The sensor body is vulnerable to damage inside the wheel if a technician is careless when using the tyre fitting machine but most of them know how to work around wheels with sensors because TPMS is so common these days.
 
Photos of a spare snap-in TPMS sensor I have for my i30 (both assembled and partly disassembled with the sensor still attached the stem).




Parts of a typical snap-in TPMS sensor


Typical snap-in TPMS sensor fitted to the inside of the wheel

[TerryT]

Vanessa, are you aware, or did your Bridgestone's invoice show, that your TPMS sensor/s got a rebuild kit fitted?  Depending on the condition of the sensors and their working life, workshops will often recommend rebuild kits.

If you got a rebuild kit, I think the TPMS sensor would be removed and its sealing rubber grommet replaced, leaving the possibility of a bad seal if the job was mishandled etc.  If a rebuild kit wasn't fitted, it is possible that the 'old' rubber grommet is not doing its job, sealing 100%.  Too many variables.

Typical rebuild kit for a snap-in TMPS sensor.


Vanessa, I think I should hold off contributing more "guessing posts" until I get some answers back from you on a couple of questions I have raised in my posts above.

Terry

[Pikapolonica]

Hi guys!  Sorry been away for a few days and haven’t been able to do any testing.

I was in the area of Bridgestone today but there was absolutely no parking.  I did call Hyundai to ask for their opinion and quoted me $170 as a start to check the sensors.

Um, no thanks.

Haven’t had a change to change the pressures yet.  Even though I was in Autobarn to buy a new globe for my headlight, stupid me forgot to look for a gauge.

I’ll keep testing the pressure over the next couple of days.

[TerryT]

Vanessa, in your last post you didn't say whether Bridgestone's invoiced you or told you they fitted rebuild kits on your TPMS sensors.