Top Gear - Bullet Train

i.g.batten@batten.eu.org gurgled happily, sounding much like they were
saying:

>> Actually, planes use nitrogen in their tyres, too. I assume it's to
>> avoid the oxidising effect of air and the water vapour.

> As do F1 cars. The coefficient of expansion is more predictable, so the
> relationship between temperature and pressure can be predicted better.

One of the "revelations" of the McLaren spying claims the other year was
that CO2 was used for inflation by Ferrari.

"Roland Perry" <roland@perry.co.uk> wrote in message
news:3Cic17I+AhfIFAFh@perry.co.uk...
> In message <0001HW.C4A3C1BD01DEF550F0407648@news.eclipse.co.u k>, at
> 15:18:21 on Wed, 16 Jul 2008, Stimpy <stimpy1997uk@yahoo.com> remarked:
>>> If you really want to stop your tyres going flat quickly fill them
>>> with CO2. Its a large molecule and will escape much slower.
>>
>>Ha! I've gone one better and filled my tyres with concrete - that doesn't
>>escape at all :-)
>
> Joking apart, whatever happened to the idea of filling tyres with some sort
> of foam-rubber compound as a run-flat precaution?


It's to hard to remove and tyre fitters hated it.

Graeme Wall wrote:
> In message <6e625cF5cflbU1@mid.individual.net>
> "Mike P" <privacy@privacy.net> wrote:
>
>> allan tracy wrote:
>>>> I liked last week when Clarkson trashed a tyre on the Bentley with
>>>> his antics - I can't see there being much change out of a £1000 for
>>>> a Bentley tyre (if any at all).
>>>>
>>>> I can never understand the reason for all the tyre smoke, it's just
>>>> pandering to the petrolheads.
>>>>
>>>
>>> I suspect that sort of driving appalls most of us with an
>>> engineering background, just can't stand watching a well designed
>>> piece of engineering being abused that way.
>>>
>>> You don't see it even in formula 1 the idea being to maintain
>>> traction not lose it so it's probably not even good driving.
>>
>> Yes you do. The optimum amount of wheelspin in an F1 car is around
>> 7-8% when accelerating out of a corner.
>>
>
> Similarly a railway loco achieves maximum tractive effort when the
> wheels are slipping slightly.

As does any wheeled vehicle.

Peter Hill wrote:

> Lets assume the fitter did it outside in the rain (like they do at the
> tyre van at race tracks

Not at any of the tracks I go to; Avon change the tyres for us in the
back of their lorry, or in a garage if they're allocated one. They will
run the wheel balancer outside though, but not the changer.

--
Abo

Abo wrote:
> Norman Wells wrote:
>> Abo wrote:
>>> Peter Hill wrote:
>>>
>>>> So so wrong. Motorsport quackery
>>>
>>> It's a tyre pressure thing. When you run for a few laps the tyre
>>> pressure changes as the heat builds up. When you fill with air this
>>> change can be unpredictable as the proportion of water vapour in the
>>> air can vary. Filling with nitrogen mans you know you have a dry gas
>>> inside your tyres and you can predict how the tyre pressures are
>>> going to change as they heat up.
>>
>> I have seldom read a more unknowledgeable account than this. Water
>> vapour has nothing whatever to do with tyre pressures, and nitrogen
>> is just as likely to contain water vapour as air is anyway.
>
> Sorry you clearly know more about oval racing than I do. Please
> explain to me why 48 or so NASCAR teams go to the bother of
> completely removing all the air from 2880 tyres and replacing it with
> nitrogen if it has no benefit whatsoever on the tyre pressure...

Since it doesn't, I can't.

Ask them.

Roger Thorpe wrote:

> I have no idea if the temperatures and pressures that I have chosen are
> realistic, but 2% is in the insignificant region I'd say.

Sorry; meant to add: NASCAR will use pressures up to 45psi (3.1 bar?)
and experience temperatures up to 150^oC

--
Abo

Norman Wells wrote:
> Abo wrote:
>> Norman Wells wrote:
>>> Abo wrote:
>>>> Peter Hill wrote:
>>>>
>>>>> So so wrong. Motorsport quackery
>>>>
>>>> It's a tyre pressure thing. When you run for a few laps the tyre
>>>> pressure changes as the heat builds up. When you fill with air this
>>>> change can be unpredictable as the proportion of water vapour in the
>>>> air can vary. Filling with nitrogen mans you know you have a dry gas
>>>> inside your tyres and you can predict how the tyre pressures are
>>>> going to change as they heat up.
>>>
>>> I have seldom read a more unknowledgeable account than this. Water
>>> vapour has nothing whatever to do with tyre pressures, and nitrogen
>>> is just as likely to contain water vapour as air is anyway.
>>
>> Sorry you clearly know more about oval racing than I do. Please
>> explain to me why 48 or so NASCAR teams go to the bother of
>> completely removing all the air from 2880 tyres and replacing it with
>> nitrogen if it has no benefit whatsoever on the tyre pressure...
>
> Since it doesn't, I can't.
>
> Ask them.

See that response below from Roger; it would appear that it does

--
Abo

Abo wrote:
> Norman Wells wrote:
>> Abo wrote:
>>> Norman Wells wrote:
>>>> Abo wrote:
>>>>> Peter Hill wrote:
>>>>>
>>>>>> So so wrong. Motorsport quackery
>>>>>
>>>>> It's a tyre pressure thing. When you run for a few laps the tyre
>>>>> pressure changes as the heat builds up. When you fill with air
>>>>> this change can be unpredictable as the proportion of water
>>>>> vapour in the air can vary. Filling with nitrogen mans you know
>>>>> you have a dry gas inside your tyres and you can predict how the
>>>>> tyre pressures are going to change as they heat up.
>>>>
>>>> I have seldom read a more unknowledgeable account than this. Water
>>>> vapour has nothing whatever to do with tyre pressures, and nitrogen
>>>> is just as likely to contain water vapour as air is anyway.
>>>
>>> Sorry you clearly know more about oval racing than I do. Please
>>> explain to me why 48 or so NASCAR teams go to the bother of
>>> completely removing all the air from 2880 tyres and replacing it
>>> with nitrogen if it has no benefit whatsoever on the tyre
>>> pressure...
>>
>> Since it doesn't, I can't.
>>
>> Ask them.
>
> See that response below from Roger; it would appear that it does

What response below what?

Roger Thorpe wrote:

>> Sorry; meant to add: NASCAR will use pressures up to 45psi (3.1 bar?)
>> and experience temperatures up to 150^oC
>>
> I see, given that what I calculated was a sort of worst case, could we
> say that "some may consider the effect to be negligible"?
> This makes us all sort-of-right (my preferred outcome).

Heh, can we go to the pub now? ;)

--
Abo

Norman Wells wrote:
> Abo wrote:
>> Norman Wells wrote:
>>> Abo wrote:
>>>> Norman Wells wrote:
>>>>> Abo wrote:
>>>>>> Peter Hill wrote:
>>>>>>
>>>>>>> So so wrong. Motorsport quackery
>>>>>>
>>>>>> It's a tyre pressure thing. When you run for a few laps the tyre
>>>>>> pressure changes as the heat builds up. When you fill with air
>>>>>> this change can be unpredictable as the proportion of water
>>>>>> vapour in the air can vary. Filling with nitrogen mans you know
>>>>>> you have a dry gas inside your tyres and you can predict how the
>>>>>> tyre pressures are going to change as they heat up.
>>>>>
>>>>> I have seldom read a more unknowledgeable account than this. Water
>>>>> vapour has nothing whatever to do with tyre pressures, and nitrogen
>>>>> is just as likely to contain water vapour as air is anyway.
>>>>
>>>> Sorry you clearly know more about oval racing than I do. Please
>>>> explain to me why 48 or so NASCAR teams go to the bother of
>>>> completely removing all the air from 2880 tyres and replacing it
>>>> with nitrogen if it has no benefit whatsoever on the tyre
>>>> pressure...
>>>
>>> Since it doesn't, I can't.
>>>
>>> Ask them.
>>
>> See that response below from Roger; it would appear that it does
>
> What response below what?

<sigh>

Look a bit further down the thread. Read the posts from Roger Thorpe.

--
Abo