over inflated tyre.. 82psi!!

[Andyoldgit.]

Hi guys. On thursday of last week i had two new tyres fitted to the rear of my Z4, Continental sport contact 5. On Friday morning I set off for Oulton park circuit and had a great werkend watching the Mini Miglia racing. I came back up the road to Inverness yesterday and was almost home when the tyre pressure light came on. Everything seemed fine so i drove the last 5 miles to home and checked the tyre pressures. One of the rear tyres was at 82psi!! Now im no expert on these things but as it says 51psi max on the tyre and i had just driven 700 plus miles on this tyre. Will the tyre be damaged by this? It looks fine but i dont know if it might be weakened in any way. Please offer any advice as to what i should do. Demand a new tyre? Just forget it and count myself lucky it didnt go bang? Will it be ok?

Thanks in advance.

Andy.

 

[mr wilks]

82psi 700miles have you any teeth left
Id drop at least 42/45 out & enjoy the new improved ride

 

[Andyoldgit.]

As you can see from the picture the tyres look fine. Im just goung to put them back on and hope for the best.

Here is a picture of the old tyres, one of them was pretty bald on the inside edge. Camber issues? Can this be adjusted ?



New tyres are continental sport contact 5.



Hope they will be ok.

 

[sars]

Tricky one, as you've driven away from the tyre place they have plausible deniability, however 700 miles with pressures well in excess of the design pressure would leave me feeling uncomfortable with their condition.

 

[paddy wright]

Ive just bought a replacement rear wheel for my z as the one on mine is cracked. It came with a tyre that I will replace with a new one to match my other side. I think it was a conti sport contact with reasonable tread (ill check when I get home) if it has a good tread you can have it for £40 posted if you like?

 

[85genius]

I filled 2 of my tyres to over 90psi :?

Last year in Germany thought it would be prudent to check my tyre pressures prior to a bit of high speed autobahn driving, the air machines were analogue jobbies and I didn't understand how to use them too used to the digital type. Anyhow had it plugged in pumping air for ages nothing semmed to be happening needle only creeping slightly, so tried on the next wheel same thing happening.... Called my mate over who quickly points out what a pillock I am!!

One was around 100psi the other was low nineties...

only for a minute or so before I dropped them back to a normal pressure but they were fine after that and was on the same tyres for at least 9 months later with no issues, it did cause the tyre pressure sensor to go nuts for a while so was a good 100 miles before I got DSC and ABS back

 

[Bing]

So are you sure that it was the fitters that did that ? I'd have thought the light would be on immediately if it was that much over pressure when you drove it off, if you hadn't reset the system as you should have done.

It could actually be heat - when my front caliper was sticking the brake, wheel and tyre got ridiculously hot and set the light off. I didn't even know it worked for increased pressure. Go for a decent drive and some good braking then test the temp of each rear wheel and brake. If one is sticking it will be way hotter than the other. It's a common issue on these cars, requiring you refurb or buy a new or refurbed caliper.

 

[pvr]

Bing - if both sides were over inflated, the sensors would not trigger as they are based on differential between the two.

 

[Bing]

Bing - if both sides were over inflated, the sensors would not trigger as they are based on differential between the two.

I'm assuming from the first post it was only one that was overinflated - and I'm suggesting that heating of the air in the tyre has caused the pressure to increase....

 

[GreyZed]

Ha ha in your pic it looks like one of the tyres is actually bigger due to the 82psi! :lol:

I'm sure it will be fine.

 

[pvr]

Bing - if both sides were over inflated, the sensors would not trigger as they are based on differential between the two.

I'm assuming from the first post it was only one that was overinflated - and I'm suggesting that heating of the air in the tyre has caused the pressure to increase....

Hate it when you are right

 

[TR4man]

I'm amazed that you could drive 700 miles and not feel that something wasn't quite right with the handling

However, there would be no harm in contacting the tyre fitting place and ask for their comments (if it was one of the national chains I'd drop an email to their head office). You have nothing to lose.

 

[Bing]

As well as checking for a sticky / seized caliper, it would be worth getting a 4 wheel alignment done too. The stock suspension set up on our cars leads to more wear on the inside edge as normal, but if both those old tyres are the same age it's strange the wear is so different.

 

[EdButler]

How did you measure the tyre pressure? I have a Ring automotive car pump that is usually pretty accurate based on what the petrol stations say, however sometimes it goes a bit nuts and goes into the 90's when they obviously aren't...

 

[cj10jeeper]

Bing - if both sides were over inflated, the sensors would not trigger as they are based on differential between the two.

I'm assuming from the first post it was only one that was overinflated - and I'm suggesting that heating of the air in the tyre has caused the pressure to increase....

Just as a rough guide each increase of 1c increases pressure by 0.2 psi.
You'd need around 250c increase to get from 30 to 80psi :roll:

 

[Bing]

Bing - if both sides were over inflated, the sensors would not trigger as they are based on differential between the two.

I'm assuming from the first post it was only one that was overinflated - and I'm suggesting that heating of the air in the tyre has caused the pressure to increase....

Just as a rough guide each increase of 1c increases pressure by 0.2 psi.
You'd need around 250c increase to get from 30 to 80psi :roll:

To be honest, I'd be surprised if the temperature of my brake was much less than that when my caliper stuck - I couldn't get my hand near it at all and the metal cooling sounded like it was cracking. The heat from the brake heating the air in the tyre must have been what set the pressure warning off because it certainly wasn't flat. So perhaps worth checking, just in case, before going off on one at a tyre fitter who did their job 700 miles before anything was evidently wrong ? Just some advice based on experience :roll:

...and if the standard pressure for a rear is 35/36 you can knock up to 30c off that 250.

 

[obewan]

Sounds to me like the fitters haven't dropped the pressure after getting the tyre to 'pop' on to the rim
Co-incidentally i was talking to a a fitter on Fri whilst he put a tyre on the wife's car.-
i asked him what sort of pressure it took to make this happen. He stated a normal tyre was around 50 psi but he had had run flats up to 80-90

 

[Worcester_spoon]

I'm assuming from the first post it was only one that was overinflated - and I'm suggesting that heating of the air in the tyre has caused the pressure to increase....

Just as a rough guide each increase of 1c increases pressure by 0.2 psi.
You'd need around 250c increase to get from 30 to 80psi :roll:

To be honest, I'd be surprised if the temperature of my brake was much less than that when my caliper stuck - I couldn't get my hand near it at all and the metal cooling sounded like it was cracking. The heat from the brake heating the air in the tyre must have been what set the pressure warning off because it certainly wasn't flat. So perhaps worth checking, just in case, before going off on one at a tyre fitter who did their job 700 miles before anything was evidently wrong ? Just some advice based on experience :roll:

...and if the standard pressure for a rear is 35/36 you can knock up to 30c off that 250.

Have we found a use for out £1 digital thermometers? We'll all be checking tyre temps and pressures before and after a drive to see the change... Fun!

 

[cj10jeeper]

I'm assuming from the first post it was only one that was overinflated - and I'm suggesting that heating of the air in the tyre has caused the pressure to increase....

Just as a rough guide each increase of 1c increases pressure by 0.2 psi.
You'd need around 250c increase to get from 30 to 80psi :roll:

To be honest, I'd be surprised if the temperature of my brake was much less than that when my caliper stuck - I couldn't get my hand near it at all and the metal cooling sounded like it was cracking. The heat from the brake heating the air in the tyre must have been what set the pressure warning off because it certainly wasn't flat. So perhaps worth checking, just in case, before going off on one at a tyre fitter who did their job 700 miles before anything was evidently wrong ? Just some advice based on experience :roll:

...and if the standard pressure for a rear is 35/36 you can knock up to 30c off that 250.

More academic discussion here but no way is a hot caliper even if say 500c going to heat a tyre that much. Distance from tyre for convection, air movement driving, lack of conduct of heat from caliper to carrier to hub to flange to rim to tyre.

Separately rubber starts to melt at around 180c

I'd firmly blame tyre inflation person or equipment.

 

[Bing]

Fair point - though from what've can find out tyres don't actually melt, though they will soften and deform. Not sure at what temperature, still looking. In the meantime, what about if it was left overinflated by the fitter and then heat from a sticky caliper pushed the pressure up more ? Why it took 700 miles for the sensor to decide to alert the OP is still a mystery - why does nobody else think that's weird ??