Tyre Pressure Warning Trigger Level

[OldTrout]

My tyre pressure warning light came on today.

The pump at the garage suggested that my front tyres were 28 and 29 psi. I set the system when I had inflated to 35 last time with the same pump.

7 psi down strikes me as a big drop.

How many psi down should trigger the warning system?

John

[KayCee]

its about 4 tp 5 psi

[royoftherovers]

Funny John, my light came on last week.

I was surprised that the system did not tell me which tyre needed attending to, so I checked all 4.

All 4 were reading approx 15psi ! Either my gauge was wrong or the system should have alerted me sooner.

I inflated all 4 to 35 psi.

Must check more regularly now.

Regards

John

[Mike Hartland]

I have had the warning lights come on with this Lexus and my previous one. in both cases they have lost around 6psi when checked. I don't know at what pressure they would be regarded as unsafe, but I agree that I would like to see them on sooner.

[OldTrout]

Thanks for replies.

I think 5psi drop on 35 is just acceptable.

Any more is not and 20psi drop is serious.

I notice the handbook gives no tolerance for the pressures.

I will not rely on my warning system in future but on visual inspection.

I had though they looked a little soft a couple of weeks back but no warning light until this week.

No point in a system if it can't be relied on.

John

[Zotto]

May be you don't consider that you have, after inflating tyres, push the hidden set button to memorize the right inflation pressure: if you have a wrong setting, you could have a warning too late (or soon).

[OldTrout]

Thanks Zotto.

I didn't rest this time but I did the time before at 35.

You have given me an idea.

Inflate all to 38psi, reset, then let them down to 35.

The warning might then kick in about 32psi.

What ever happened free air?

The last but one time cost me 50p. Yesterday I had to have two lots of 20p despite getting all the caps off first.

John

[AmbroseJohn]

I think you can set the levels using Tech Stream. If they're set at 20psi that's when the light comes on.

[dave1]

On 1/18/2016 at 11:52 AM, OldTrout said:

 

What ever happened free air?

The last but one time cost me 50p. Yesterday I had to have two lots of 20p despite getting all the caps off first.

John

Invest in an inflator that plugs into lighter/accessory socket, easy then to check weekly at home when tyres are cold to get correct pressure. It will soon pay for itself.

[OldTrout]

1 hour ago, dave1 said:

Invest in an inflator that plugs into lighter/accessory socket, easy then to check weekly at home when tyres are cold to get correct pressure. It will soon pay for itself.

Thanks dave1.

I had no idea they were so cheap. I have ordered one which should be here tomorrow. I dug out my old pressure gauge yesterday and checked the tyres I inflated to an indicated 35psi lest than a week ago. The pressures varied from 28 to 34 on my single gauge!

I don't know what the measuring accuracy of this gauge is but there is no warning light.

John