Spare Tyre drama

[skyblues11]

What a day!

I was on my way to Liverpool airport from Cannock. Within 5 min of leaving home, a passing driver pointed out to me that i have a flat rear tyre.

I stopped and with the sidewalls rubbing already, i would not have made it home to fit one of the summer wheels. With time ticking away, i put that skinny spare on and drove on at about 55mph all the way.

My question is, why the onboard VW tyre monitor did not make a sound? surely the circumferance would have complete changed?...how long does it need before it realises? I think the tyre was well flat when i left my house.

I have bought one of those after market TPM where you fit a thumb size monitor onto the valve.The night before i had removed them ( stupid me) , as i will leave my car in the airport for 10 days ( the decision had nothing to do with Liverpool) and soon i will swap the winters over to the summers. The tyres were ok then.

Not finished with that, as i stopped at that Runcorn bridge traffic jam, the VW tyre symbol finally lit up on the dash, some 1hr after the event. Also, the ESP failure message came on.


It was the most stressful 10 miles i have ever driven! i did not know whether another tyre was loosing pressure.

I made it in the end and checked in ok. The plane was delayed as well and a young couple with a crying baby sat in the row behind...

As i am looking back on the day from my Barcelona hotel, why did the VW tyre monitor did not sound when it should? And what is that got to do with the ESP failure? Shall i drive it to a liverpudlian VW dealer and get the ESP warning reset when i return?

anyway, an important lesson today - always check your tyres visually and physically. Do a full circle inspection regardless of the weather once a day.

[JakeH]

Sorry to hear that skyblues - just what you don't need with the hassle of the airport and flight! I was wondering how effective the flat tyre warning was. I noticed my front passenger tyre was looking a bit flat a few days ago and after checking further found a metal spike sticking out, but I couldn't understand why the flat tyre monitor thing hadn't lit up. Obviously I'm not the only one. Hope you get it sorted.

[bianco]

I installed OEM flat tyre monitor my self, and wanted to check it.
Went on a drive straight after installing (and resetting) it. Let out most of the air, but no reaction.
I then read that it takes up to 100 km to set itself.

After driving 2-300 km, I let out 1/3 of the pressure, and the light and ding came on after 500 m driving.

Did You have the car for service? Have a curious teenager in the passenger seat? They might have pushed the reset button.

[RW1]

A bit of a fag at the start of a holiday, last thing you need.

Some thoughts for starters............

The TPMS has limitations as I found out during testing the VCDS set-up installation (No wiring & no Reset button version - same as VW's TPMS installation in use). Certain levels of deflation are tolerated. Its not a leak tester system. In fact during the testing I found I could drive miles without the system triggering the dash light alerts. As you both don't mention actual pressure changes, its difficult to comment exactly.

Some explanations of the TPMS here ... http://www.sciroccocentral.co.uk/forum/ ... ilit=+tpms" onclick="window.open(this.href);return false; Just read the topic as the same as the TPMS switch fitted by VW.

Stage 4: Educate TPMS for learned values

During learning/calibration mode the system can only detect changes in tyre pressure of about 10psi. On maturity of the learning process this improves to detecting about 4 - 5 psi drop before the speedo dial tyre warning symbol comes on.

@skyblues, possible explanation for the deflated tyre is when the pressure sensor heads were taken off the tyre valves, the valve of the rear one didn't fully seal. I've on a couple of occassions, when checking inflation pressure using a tyre pressure gauge, had the VW tyre valve stick very slightly open. You make no mention of a screw/nail puncture, so I wonder if the tyre valve was stuck open ever so slighly overnight.

@JakeH
Maybe the deflation hadn't gone far enough to get to the point outside the parameters above in the quotes.

..............

And if the TPMS button has been reset recently, the wider tolerance of 10psi could be in place. The button may not have been pressed recently but the system is not instant afterwards to become fully tuned up to the 4 - 5 psi.......

Stage 4: Educate TPMS for learned values

Just drive the Scirocco. It takes about 60 miles at various speeds upto 70 mph driving for the system to fully "learn" as it does with the TPMS button factory option. If you only do urban driving it will take a lot longer, about 550 - 600 miles. It needs at some point to see a higher rotational speed for a while to complete.

One test run based on urban driving since I wrote the "550 - 600 miles" above, I gave up as the system had not calibrated at 1,000 miles so its detection tolerance was still wider at 10psi.

And another factor I observed was that replacement tyres affect the time it takes a slow driving style (urban crawl) to reach full effectiveness. The system has a vibration component in its calculations and the standard of the replacement wheel/tyre balance does increase calibration period before full tune is acheived.

I, as said, still visually check my tyres once a week and pressure test once a month as a result of what I have found with VCDS testing.

Without more detail of actual tyre pressures before & after, when was the TPMS last reset and how was it driven since the TPMS Reset, its difficult to offer further.

C.

[skyblues11]

I did recall reseting the TPMS (the VW one) after fitting the winters on. Then did nothing since. I think i did more than 600 miles since.

I did not have a chance to check the tyre as i was in such a hurry. The stuck valve sounds plausable because with those aftermarket TPMS (http://www.tyrepal.co.uk" onclick="window.open(this.href);return false;) you have to screw those sensors onto the valve and keep it depressed. When i unscrewed it the pin may have not bounce back up to close...

if this is the case i should expect the 3 other tyres completely deflated when i get back...

after fitting the skinny spare, i tried to reset the VW TPMS as that was my only back up, but did not find the botton and i was also driving as well. Perhaps it only sounded later because it had only learned the new circumfrance after an hour of driving.

i will get the tyre checked and see what happend. Maybe repair it ( if its repairable) and keep it as a winter spare.

With the tyre side more or less understood, but why did the ESP fail?

[RW1]

With the tyre side more or less understood, but why did the ESP fail?

The ESP is part of the Brake Controller, same as TPMS is. So I'm inclined to say sort the tyres out, reset the TPMS again and then drive and see if the ESP returns. I don't think it was at fault, just a side effect of your unfortunate circumstances.

Thats quite a neat gadget. Pity, as it wouldn't stay put round my way!

C.

[JakeH]

That's a good read RW1, many thanks for your advice/help.

[skyblues11]

perhaps the ESP won't work properly when the skinny spare is fitted.

thanks RW1 and lets see what happen next week....