Yes, in Figure 6, I don't understand why the effective radius is not the distance OQ. Or OP-z, if you prefer. I presume they are allowing for the fact that the radius varies between maximum OP (at the edge of the contact patch) and a minimum OQ (at the centre of the contact patch), and that the effective radius is somewhere between the two and not the minimum OQ.
It does not though, obviously (or iTPMS systems wouldn't work).
Science.
To you unfortunately it seems. To people who understand these things it's key.
Cheers, T i m
So are saying the circumference remains constant, hence the rpm remains constant, hence iTPMS cannot work?
But as others have pointed out in this thread, it's less than 1%. Or are you saying that 1% is what the argument is about?
If the perimeter of the tyre makes one revolution, the vehicle moves forward by 1.5 metres in my example, regardless of the shape of the tyre. It could be oval, or even square with each side 0.375 metres, but only in Michael Bentine's world :-), but the vehicle still only moves forward 1.5 metres per revolution of the tyre, and with a square tyre the axle to ground distance would be changing all the time (giving a very uncomfortable ride!)
So dragsters use big tyres; so do earth moving scrapes and dumpers, even bigger than those on the dragster.
But the 'give' in a car tyre, as has been said here by others, is less than 1% between hard and soft, over and under inflated. Is that the difference you're considering? If so, then OK I agree with you, a change in tyre pressure will result in a small Cheers, T i m
I'm not stating anything so specific Chris but yes, that could possibly be the sort of numbers we are talking about.
How does that relate ITRW. Well, a tyre that is running at a lower pressure will rotate more time that will relate to a whole mile in every 100. The point being that 1% doesn't sound like much but a mile is quite a way (especially if you are walking with a flat spare to a garage). ;-). ;-)
Ok, try this (and try to go with the concept rather than the details for now). Imagine because how a tyre is constructed, steel wires laid using a parallelogram pattern that 'pantographs' (think pantograph on an electric train that gets wider as it gets lower) where it touches the ground and that causes it to widen (width) but because the material it is widening by has to come from somewhere, it also shrinks (length = circumference). So, there is a traveling 'shortening' of the 'effective circumference' that is partially dependant on the *amount* the flexing happens and that is down to the pressure.
Yes but you are missing how the size (change) is relevant here.
There shouldn't be (and the point of having a 'burn out')
Yes. ;-)
Yes. ;-(
To get the rubber hot to give more traction and a better launch.
I know. As others have said, I'm sorry I don't seem able to transfer the understanding. ;-(
Yes ... ?
No, I don't think it is, or the iTPMS might not be able to deal with tyre wear (even though they could from a programming POV etc)..
See above (I think it's bigger).
As long as you are happy with the fact that it does and why, is all that matters Chris. ;-)
Cheers, T i m
Yup, he is (obviously), but he's a fanatic Brexiteer so since when has logic / fact / reason influenced his thinking. ;-)
Cheers, T i m
[1]
I did not say there are no asymmetries between the hemispheres. I do say that IMLE your generalisation is not shared by the practising neurosurgeons, neurologists and neuropsychologists I've heard comment on the matter. You may of course be better qualified than them or have access to better advice. But there are many others who agree with the OECD. I am told functional MRI is particularly persuasive in this regard[2].
But I don't really expect to persuade you. The left-brain/right-brain myth has become a metaphor for different ways of thinking which may never die. And it is of course also a wonderful way to peddle pseudo-psychology - or cast aspersions.
[1] though I must say I thought calling the corpus callosum a "point" a bit like saying there's only a few dozen lines for calls across the Atlantic [2] : eg"we demonstrate that ...do not result in a subject-specific global brain lateralization difference that favors one network over the other (i.e. left-brained or right-brained).
"Yet our analyses suggest that an individual brain is not ?left-brained? or ?right-brained? as a global property, but that asymmetric lateralization is a property of individual nodes or local subnetworks, and that different aspects of the left-dominant network and right-dominant network may show relatively greater or lesser lateralization within an individual. "
If by "effective radius" you mean the rolling radius it is the only relevant measure to combine with the angular velocity in order to arrive at the speed of the vehicle[1]. If you dispute that please post your equation.
Or of course you could admit that by circumference you mean the rolling circumference - defined as 2 x Pi x the rolling radius - which changes with pressure.
If you were to measure the speed of rotation of the wheel at any single point on it, that would vary depending on where it was to the road contact point. Virtually no drive mechanism transmits a perfectly uniform speed from input to output. There is invariably a degree of 'chatter'.
The ABS sensor will measure the speed multiple times (e.g. 48) per revolution of the drive shaft, not just a single point.
The TPMS operates over a longer period of time, probably minutes rather than seconds, so over many revolutions of the wheel, likely the numbers will get averaged out before it decides one wheel is turning faster than the others enough to flag it up.
It *has* to integrate over a fairly long time and number of rotations to avoid it being triggered every time the car turns a corner and the outer wheel rotates faster than the inner wheel. I would imagine (and I've not done the calculations) that the difference in rotational speed between inner and outer wheel on a bend will be significantly more than the difference in rotational speed between a correctly-inflated and an under-inflated wheel, so any TPMS has to average out this large difference in order to be able to detect a much smaller one.
defenders and freelanders never a disco
Or, given that it knows the steering wheel angle, it might chose to ignore readings during turns.
I'd say much greater
Ok ...
Assuming you fully understand whatever you are determine to be 'my generalisation' etc?
Nope, but the information in the scientific, peer tested link I provided seemed to?
I'm sure there are ... like the flat-worlders still out there. ;-)
You don't need to Robin as 1) it doesn't really matter to you what I 'believe' and 2) it doesn't matter to me what you believe (or think I believe) either.
Ok. Do you think we (not me of course), fully understand how the human brain / mind / memory etc works? Do you think you do maybe?
It's true that I sometimes like to use it when thinking out loud to differentiate different types of people, how they think and therefore why they might say the things they do.
For you to say such authoritatively you would have to be in a position to counter all the evidence supporting that brain lateralisation does exist (and it does).
If the cap fits?
A good example of a 'left brainer' / literal interpretation on my very simple yet accurate statement. eg. If you look at the comparative land masses of the UK and the USA and then the size of ALL the cables between them, they wouldn't even register on that scale.
Yet different people demonstrate different characteristics that seem to fall into specific groupings? Have you not noticed a link between those who do and don't understand the topic of this thread and their position on Brexit for example? Could it be that someone willing to completely ignore the feelings of between 1/2 and 2/3rds of the electorate might consider others differently to someone who wouldn't?
Bingo.
Sorry, what that supposed to disprove my basic concept Robin? ;-)
OK, try this. Do you feel that women are generally more empathetic than men (and if they are, why that might be)?
If you do then you have already accepted that people can be different and based on specific criteria (re EQ in this context) and probably on a testable (and even measurable, MRI etc) scale.
So, if you have a stroke in the left side of your brain, why are you statically more likely to have problems with speech than people who have a stroke in the right hemisphere?
If both hemispheres (typically) dealt with the exact same things at the same level why wouldn't it be 50:50?
Cheers, T i m
The steel cords may stretch a little, but that's all. Without that, the circumference *must* stay constant.
The steel belts aren't parallel to the circumference, they're on a low angle diagonally, so they can bunch-up or space-out with the distortion of the tyre as it revolves, so the change in circumference can be more than just you'd get by stretching them, though it still only needs to be small to be measurable.
They don't stretch, they *move*, along with the rubber.
What's that ... is the penny slowly dropping? ;-)
Cheers, T i m
OK. But that's what what has been being argued about at least in this portion of the thread. People keep talking about the centre of the wheel being closer to the road, which it is, and taking the centre-road distance as a radius and computing a new circumference based on that, which would be considerably more than 1% different from that for an inflated tire.
Which is what matters when computing the speed of the wheel with a flat tyre against one with a fully inflated tyre, or the figures for that.
What about compression at the point of contact with the road? Using Andy's diagram, the circumference has been shortened by APB - AQB.
the-contact-patch.com/book/road/c2020-the-contact-patch#figure-ERr
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