Wrong kind of tyre pressure

[Andy Burns]

I would mostly agree, I didn't pay to have TPMS on my car, but via the OBD port you can enable it, so I did. It is the version that doesn't have actual pressure sensors, but senses speed differences between wheels using the ABS sensors.

It differentiates between slow and rapid changes, giving a yellow or red warning on the dash, when the yellow one goes off I've generally been aware for a day or two on speed humps or cornering that it's getting a bit soft, and not got round to topping them up.

But once, on the motorway, the red warning went off unexpectedly, when I hadn't felt anything, as it happened I was a few hundred yards from a service station so I pulled in there rather than onto the hard shoulder, by the time I'd parked one rear tyre was totally flat from a shard of glass. Obviously I would have noticed that at some point, but perhaps the tyre would have shredded itself by the time I could do anything about it?

[Steve Walker]

Yes. Older cars made it very clear when a tyre was even a little bit low, but modern ones seem to be set up much better and it isn't always obvious.

SteveW

[charles]

Power steering is to blame

[Terry Casey]

One of these:

or:

Mine also has the tyre pressure checker:

16969_zoom.jpg

or:

When applied to the sensor, a magnetic field turns the sensor on briefly while the pressure is read.

Because of my bending problems, this is the most useful feature of the system.

On my previous (02 Reg) Focus, my wife could always tell me when the nearside front tyre pressure was low - often not much more than 1 psi (!) - but with the current (61 Reg) model, she can't tell any more!

[James Wilkinson Sword]

But it does help if you have a blowout. I had a blowout on a car (both on the motorway at about 90) with and without power steering (both cases front tyres). The power steering car wobbled a bit, the other one required a heavy wrench of the wheel to maintain a straight line.

[James Wilkinson Sword]

Wow, 38's a bit high. I've always put 30 in all car tyres, and 40 in mountain bike tyres.

[fred]

I understand Rolls Royce use it and claim reduced tyre noise

Incidentally my car gives pressure and temperature readings

[tabbypurr]

sellers do tend to claim things. Work it out and you'll notice the difference is not detectable IRL

NT

[fred]

On Sunday, December 17, 2017 at 6:51:25 PM UTC, James Wilkinson Sword wrote :

:

ntain bike tyres.

So what degree of accuracy should one aim for ?+/- 1 p.s.i. ? I have three different gauges and they all differ. One is the old pencil type which I al ways assume to be fairly accurate. Another is a Halfords digital one and t he last is on the airline. I find the bar reading too coarse

[James Wilkinson Sword]

I don't think tyres are that fussy. If in doubt about a guage, just pump until it looks round.

[fred]

ote:

mountain bike tyres.

ree different gauges and they all differ. One is the old pencil type which I always assume to be fairly accurate. Another is a Halfords digital one a nd the last is on the airline. I find the bar reading too coarse

until it looks round.

Troll troll troll

[Tim+]

Only just realised?

Having said that, there is an element of truth in what he says.

A sidewall that is obviously bulging too much leads to overheating and blowouts. Pumping up to reduce the bulge brings a tyre back into the correct shape to reduce this.

If you load your car heavily without upping the pressure, you?re back to having bulgy sidewalks and risk of blowout so by upping the pressure, you?re making your tyres ?round? again.

Tyre pressure is just a useful means to an end to make sure that our tyres are the right shape for best grip and least overheating. It?s a lot easier to measure than ground to wheel centre distance say or tyre-wall bulge.

Tim

[James Wilkinson Sword]

Then you'd be wrong.

And have just proved yourself so.

Light travels faster than sound. This is why some people appear bright until you hear them speak.

[Jimbo]

better with a set of groundhogs...tee hee

[James Wilkinson Sword]

Aren't they furry animals?

[Jimbo]

no

[James Wilkinson Sword]

Can you get them for

?

[Dave Plowman (News)]

Very difficult to tell with big low profile tyres.

[James Wilkinson Sword]

I never had that problem with mine. If the tyre is considerably thinner at the bottom than the rest of it, it needs more air.

[Rob Morley]

I noticed that recently. Hard to see much difference between 20PSI and

45PSI. I usually inflate until a tyre looks about right, then check it with a separate gauge, because pump gauges tend to be inaccurate.