Tyre Pressure Help

[MJCTHR]

Hi guys. I hope someone can give me some advice.

I bought an MG5 Long Range Trophy FL in Nov 23 (72 plate) from a Wilson's dealership. The tyres were inflated to 2.1 bar. It had its first service in Nov 24.

I don't drive great distances, I've only done 3k miles in just over a year. I did do a 110 mile round trip to Essex from South London for Xmas though.

I went out this morning and the TPMS quickly flagged that the tyres were ALL under pressure at 1.8bar. This seems a bt strange to me. Could it be something to do with the cold weather? I have a tyre inflator but want to be confident pumping the tyres up to the correct pressure. The manual says the tyres should be 2.2 bar but Wilson's have always pumped them to 2.1 bar.

Any advice would be greatly welcomed.

 

[Verdigris]

The pressure will decrease in cold weather. Just go for a drive and the tyres will warm up and the pressure will go up again..

 

[Alb]

It's just the ambient temperature. Just pump them up to the correct pressure (cold) and you're good to go

 

[Verdigris]

It's just the ambient temperature. Just pump them up to the correct pressure (cold) and you're good to go

Then they be too high when the weather/tyres warms up, The main thing is to fill the tyres at a medium temperature, around 15 degrees, and then any variance, up or down, will be within reasonable limits.

 

[Alb]

Completely wrong I'm afraid.
You should be checking tyre pressure (and condition) on a routine basis and adjusting as necessary. They should be set (in the case of my MG5) to 32psi regardless of whether it's August or January.

 

[Verdigris]

I didn't say you shouldn't check the tyres regularly, for damage and evenness of pressure. What I did say is that it isn't wise to use the "factory setting" at extremes of ambient temperature. If you find a tyre looking a bit flat on a cold day, then check the other pressures and set the flat tyre to that. They will then remain even when things warm up.

 

[MJCTHR]

Thanks for your insights. I did notice the manual says to set the tyres at the correct pressure when it is cold so I'll do that, but it's nice to know that the app alarms weren't really bad.

I also read on another thread that someone said to set pressure higher for better range so I am guessing topping up the pressure when cold won't be too damaging. I'll deffo keep a close eye on the pressures going forward.

 

[Verdigris]

Yes, higher pressures reduce rolling resistance. They also reduce grip.

 

[MartinSEsr]

The pressure will decrease in cold weather. Just go for a drive and the tyres will warm up and the pressure will go up again..

No, the required pressure is the cold pressure. Blow them up to the correct minimum of say 2.5 bar (I use 2.6) while cold. The pressure will go up when driving, it is designed to correctly if the specified pressure is set when cold. You absolutely should not be driving with a datum pressure of 1.8 bar (thanks Alb, corrected from psi).

If you set to say 2.6 bar in the summer, you need to re-inflate in winter as the say 20 deg drop in ambient temp causes a large drop in baseline pressure.

NB, after much testing and monitoring, playing with things, I found tyre pressure had by far the largest effect on improving Miles per KWh, with a real improvement moving from 2.3 to to 2.7 bar. 2nd largest influence was the heater, third and with little effect was a/c, and eco did absolutely nothing except dampen the throttle and brakes.

 

[Alb]

You absolutely should not be driving with a datum pressure of 1.8 psi.

Or even 1.8 bar