Tyre advice

[andi]

We also keep a repair kit in the car. You will find other threads on this

 

[fnegroni]

I was checking the status of my Trophy's tyres after receiving a low pressure reading of 2.3bar on a cold day which I ignored and it went away when I drove this car. However, today, I got the status, with a normal statement about type pressures, see photo 1:

View attachment 33433

But when I checked I found as per photo 2:

View attachment 33434

I checked with my gauge and yes it was at 1.6bar and there was a screw in the outside raised tread. Repair will have to wait until after Christmas.

I had no alarms and, obviously, the car thinks 1.6bar is ok but 2.3bar is not. Strange software, probably using 'equals' rather then 'less than' in the detection routine.

Did you drive the car after the pressure was reported at 1.6 bar?

The app is a bit glitchy but also the app is reporting two different things: status is reported by car, pressure is reported by tpms. The TPMS doesn’t issue warnings based on absolute pressure but based on changes in pressure.
The car then reads the information from the tpms and then decides whether to issue a warning.
Therefore there’s a situation where the car issues a warning because of a previous message from the TPMS, then the warning in cleared by the car based on the subsequent readings.
If the TPMS detects a leak while the car is stationary, it will send an alert to the car, but the car will not issue a warning to you until it has had a chance to process it.

 

[dsimpkins]

If we do have to replace the tyre does anyone have any strong recommendations or warnings?

Bridgestone Turanza 6 £127.99
Goodyear Vector 4 Seasons G3 £139.99
Continental PremiumContact 7 £132.99
Michelin e.PRIMACY £154.99

I see you've already replaced the tyre, but I had a recent puncture, and wife couldn't get the tyre foam to work (tyre had a huge hole in it) It was on the rear, and ended up replacing both sides as the other tyre was starting to get low on tread when I checked.

I went for the Bridgestone Turanza 6. I got the "All season" version of it, the price above is the summer tyre. Wet grip is vastly improved over the factory option. Saving up to replace both front tyres now, but they had more tread than the rears so don't need doing quite yet.

 

[OriginalBigAl]

No one has mentioned taking the wheel off and rotating it in a bath of water. At least then you can ascertain what and where the problem is and then remedy appropriately. Unless you are carrying a jack and brace its an at home job only! but with a slow puncture most of us would be able to pump it up and get home even if we have to stop a couple of times.

 

[Martinonline]

@fnegroni, I don't know when I picked up the screw before I noticed the low pressure reading. The pressure was 2.4bar the day before but I did not check it before I travelled a short distance, parked the car and about 15 mins later checked the pressures and found the low reading. I wasn't able to look at it for a couple of hours and thought it might be an iSmart issue but, no, when I powered up the car the driver's display confirmed the reading. After pumping up the tyre I went for a little drive; the car showed 1.6bar for about 300yards then switched to 2.4bar. Since yesterday the tyre has maintained 2.4bar - I rotated the screw to ensure it was less proud on the tyre as it was obviously keeping the air in.

It's on the borderline for repair so I'll have to see what Kwikfit say.

 

[Martinonline]

I was wrong about the tyre pressure above. I was relying on the app to tell me if the pressure had decreased. I know now that it was telling old information. After a short drive yesterday the tyre warning came up at 1.1bar. I parked and pumped it up to 2.4bar. An hour later as I returned home the tyre pressure warning came at 2.3bar. After 24 hours I measured the pressure and it was down to 2.1bar. I've pumped it up and will monitor the decrease over time to see if I think the car will last the 6 miles to a kwikfit (they have declared themselves open tomorrow) or a shorter distance to my local garage if they are open.

@fnegroni, I accept your theory about the issuing of alarms; the app is now showing normal pressures after I pumped up the tyre whereas before it maintained the warning. However, my photos above show the app saying Normal but displaying 1.6bar. Based on my experience yesterday I would have thought the app would have maintained the 'Abnormal' message if it had received one until I had pumped up the tyre from 1.6bar on Tuesday.

 

[ReintjeWA]

I’ve pumped it up and will monitor the decrease over time to see if I think the car will last the 6 miles to a kwikfit (they have declared themselves open tomorrow) or a shorter distance to my local garage if they are open.

It’ll be perfectly fine to pump the tyre up to 3.5 bar for a short trip if it’s slowly leaking. Just the one trip won’t negatively impact your tyre wear, and the real danger is under inflated driving as this will overheat the tyre and destroy it from the inside.

 

[fnegroni]

I was wrong about the tyre pressure above. I was relying on the app to tell me if the pressure had decreased. I know now that it was telling old information. After a short drive yesterday the tyre warning came up at 1.1bar. I parked and pumped it up to 2.4bar. An hour later as I returned home the tyre pressure warning came at 2.3bar. After 24 hours I measured the pressure and it was down to 2.1bar. I've pumped it up and will monitor the decrease over time to see if I think the car will last the 6 miles to a kwikfit (they have declared themselves open tomorrow) or a shorter distance to my local garage if they are open.

@fnegroni, I accept your theory about the issuing of alarms; the app is now showing normal pressures after I pumped up the tyre whereas before it maintained the warning. However, my photos above show the app saying Normal but displaying 1.6bar. Based on my experience yesterday I would have thought the app would have maintained the 'Abnormal' message if it had received one until I had pumped up the tyre from 1.6bar on Tuesday.

It very well might be a bug in the app: my hypothesis originates from how the TPMS is programmed vs how the car reports from it. There seems to be a discrepancy there and that made me wonder if this in turn made the app report strange things but I accept it was really just a shot in the dark

 

[Bam Bam]

Me again!

We've had a slow puncture in the rear passenger tyre for a little while and have now spotted a screw in there.

Am thinking I will go back to the tyre place and get a matching new one.

Then ask them to move the (nearly new) front-passenger tyre to rear-driver and get the factory ones both on the front.

New question about TPMS
Can someone confirm how these TPMS work because these are new to me.

Did someone mention somewhere that you can swap the wheel locations around and the car will work out which sensors are where on the car?

So if the tyre fitter just swaps the wheels around they don't have to change any valves over or anything? The car will just work it all out?

Also - are these sensors going to run out of battery at some point and need replacing? Or do they self-charge (haha) kinetically from the motion of the wheels?

Thanks!

 

[siteguru]

The TPMS sensors in the wheels are coded to each corner ... if you move, say, front left to rear left and the (now) rear left loses pressure, the car will show the alert against the front left wheel.

 

[Bam Bam]

The TPMS sensors in the wheels are coded to each corner ... if you move, say, front left to rear left and the (now) rear left loses pressure, the car will show the alert against the front left wheel.

Oh OK, it seems I completely misunderstood.

So I would have to either get the tyre place to swap the tyres but leave the sensors in place. Or if they don't then mentally remember that the reported wheels are not all correct and should be swapped.

 

[ReintjeWA]

Most TPMS sensors have an internal button cell battery that is sadly non replaceable, meaning the whole sensor needs replacing after 5-10 years depending on use and temperatures etc.

There are some newer sensors that use radio frequency waves to relay information but I doubt MG has splurged on this technology seeing as they can’t even have the car figure out which corner a particular sensor is on. It’s a real shame and hassle the car doesn’t update sensor location by itself.

Swapping the tyres around sounds like a good plan though, especially putting the best tyres on the back for traction and grip.

 

[Joules]

When I picked up the MG4 the tyre pressures were low around 2.1, I pumped them to 2.6. Two months later they were around 2.3 but the temperature has dropped by 8 degrees. I will check them manually every month.

When I picked up my first MG4 from the dealer, they told me they had inflated the tyres to 2.8 bar as they had found this to give an even wear across the tread. They weren't wrong as 15,000 miles later I replaced the rears for Michelin Cross Climates...then they made me an offer I couldn't refuse Doh!
As far as the TPMS is concerned, I respectfully suggest you arm yourself with a tyre pressure gauge as a standard and reassurance, I've known TPMS to give false readings, though the current MG4's are quite accurate against the pressure gauge.

 

[Bam Bam]

The tyre place decided it would be better to have the new ones on the front axle.

The screw was on the side so it was unrepairable (was interested in keeping it repaired as a spare if that would have been possible).

Also due to their laziness we've ended up with the TPMS readings being in the wrong place, which we will have to remember from now on.

 

[ReintjeWA]

The tyre place decided it would be better to have the new ones on the front axle.

The screw was on the side so it was unrepairable (was interested in keeping it repaired as a spare if that would have been possible).

Also due to their laziness we've ended up with the TPMS readings being in the wrong place, which we will have to remember from now on.

Sometimes they think they know better, I suppose some people said the same about me when I sold tyres haha. On a rear wheel drive car I would recommend the back, but some people say the front because that's where you steer. Tomato/tomato sort of thing. It's a real shame MG didn't spend a little bit more money and have the car figure out which sensor is where, sort of defeats the purpose of having a per tyre read out really.

 

[DixieTGS]

It's a real shame MG didn't spend a little bit more money and have the car figure out which sensor is

And if they wanted to do it on the cheap, it would be trivial to put something in the engineering menu to allow them to be assigned manually. Working out which one is which to assign them would only be a little bit of a faff.

 

[Muffler]

And if they wanted to do it on the cheap, it would be trivial to put something in the engineering menu to allow them to be assigned manually. Working out which one is which to assign them would only be a little bit of a faff.

You'd think it would be pretty easy! The manual for my MG5 advises rotating of tyres for even wear and it also has a similar dash display showing pressure for each corner - so, Im guessing that does detect/recalibrate each wheel position to suit?

 

[ReintjeWA]

You'd think it would be pretty easy! The manual for my MG5 advises rotating of tyres for even wear and it also has a similar dash display showing pressure for each corner - so, Im guessing that does detect/recalibrate each wheel position to suit?

From the MG4 manual, so I wouldn’t take that as an indication the MG5 detects which sensor is where. I might very well do of course, but the advice to rotate tyres is just generic I think.

 

[Tig170]

Most TPMS sensors have an internal button cell battery that is sadly non replaceable, meaning the whole sensor needs replacing after 5-10 years depending on use and temperatures etc.

I've found that the Autel MX sysyem (£10/corner?) works well (fully programmble), just bought 4 X Ali express / Temu items for around £3 / unit - not checked them yet with the Autel.