On 28/06/2018 22:26, Tim Streater wrote:
In article , Jeff
wrote:

"T i m" wrote in message
...

Bingo.

I was walking round the park with our daughter earlier and I gave her
the nutshell iTPMS overview and asked her how she thought it might
work ... how the circumference could become shorter for the iTPMS to
'sense' the increased RPM.

"As the tyre gets flatter it spreads more and that makes the
circumference shorter and so the revs higher?"

Not convinced and that summary makes no sense either. Why would
the tyre 'spread more' as it gets flatter and why would the circumference
get shorter even if it did

Well it does spread a bit, see Fig 5 on:

Â*http://the-contact-patch.com/book/road/c2020-the-contact-patch

But the circumference can't get shorter except for a small amount, much
less than the "rolling radius" people like Huge andÂ* T r o l l.

Fig 5 shows what *actually* happens when the tire is deflated (although
fig 5 is about higher speed effects, supposedly). You will see it
showing the bulge on each side of the flat part. That is where the
extra circumference goes, the part that supposedly vanishes according
to fig 6. AISB, fig 6 doesn't have anything to do with reality.


Why the sudden change? Now TNP has claimed that the circumference can
change you also change to say it can.

You are a mug if you think TNP is right all the time, he isn't.
And neither are you.