Tyre pressure weirdness

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Mussels
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Re: Tyre pressure weirdness

Post by Mussels »

Does a pressure tester measure relative to air, if the atmospheric pressure goes up the relative difference goes down?
I wouldn't expect it to be enough to make a difference but if the cheap sensor cut design corners, possibly?
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Re: Tyre pressure weirdness

Post by The Spin Doctor »

Le_Fromage_Grande wrote: Tue May 17, 2022 9:22 pm But it is interesting from a perspective of those people who say they can feel the difference in 0.5 psi tyre pressure, I know I can't feel the difference 5 psi makes.
I can feel a difference of 2 psi or so in the front... but I'd never detect that difference at the rear.
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Re: Tyre pressure weirdness

Post by Mr. Dazzle »

Mussels wrote: Tue May 17, 2022 9:26 pm Does a pressure tester measure relative to air, if the atmospheric pressure goes up the relative difference goes down?
I wouldn't expect it to be enough to make a difference but if the cheap sensor cut design corners, possibly?
Sir is talking about the difference between gauge and absolute pressure. As the name suggests, gauge pressure is what gauges generally read...namely, the difference between either side of the gauge, which is most cases is just one atmosphere less than the absolute pressure.

I suppose there would actually be a sort of delay in tyre pressure change relative to the outside world as the atmosphere warms up and cools down and the air in the tyre lags a bit.

1 or 2 psi would be alot for that sort of thing though.
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Re: Tyre pressure weirdness

Post by wull »

Le_Fromage_Grande wrote: Tue May 17, 2022 9:22 pm I did say it was weird, it probably is the guage, that would make more sense, it's not exactly a scientific instrument.

But it is interesting from a perspective of those people who say they can feel the difference in 0.5 psi tyre pressure, I know I can't feel the difference 5 psi makes.
I tend to find unless it’s the best racers at the absolute limit then they’re talking pish! The kind of regular Joe’s that say that wouldn’t know their fartbox from their elbow.
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Re: Tyre pressure weirdness

Post by Le_Fromage_Grande »

42 this morning
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Re: Tyre pressure weirdness

Post by Horse »

Le_Fromage_Grande wrote: Wed May 18, 2022 7:29 am 42 this morning
Happy birthday ;)


Have you tried checking your car tyres at the same times as the bike's?
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Re: Tyre pressure weirdness

Post by A_morti »

Le_Fromage_Grande wrote: Tue May 17, 2022 9:22 pm I can't feel the difference 5 psi makes.
Was going to say - 5 psi seems to be about my "bum dyno" sensitivity on pressures. I would consider +/- 1 or 2 psi to be within margin for error, and leave it well enough alone.
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Re: Tyre pressure weirdness

Post by Tricky »

I rate this thread a 5 (+/- about 5.5 , dependant on which gauge I'm using :D )
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Re: Tyre pressure weirdness

Post by Le_Fromage_Grande »

Horse wrote: Wed May 18, 2022 7:32 am
Le_Fromage_Grande wrote: Wed May 18, 2022 7:29 am 42 this morning
Happy birthday ;)


That's Sunday, and a bit more than 42
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Re: Tyre pressure weirdness

Post by Skub »

Don't let the pressure get to ya.
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Re: Tyre pressure weirdness

Post by A_morti »

Le_Fromage_Grande wrote: Wed May 18, 2022 9:08 am That's Sunday, and a bit more than 42
Is it 43.5? Cos that sounds like free bar to me...
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Re: Tyre pressure weirdness

Post by Le_Fromage_Grande »

A_morti wrote: Wed May 18, 2022 1:12 pm
Le_Fromage_Grande wrote: Wed May 18, 2022 9:08 am That's Sunday, and a bit more than 42
Is it 43.5? Cos that sounds like free bar to me...
That's weak
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Re: Tyre pressure weirdness

Post by Yorick »

A_morti wrote: Wed May 18, 2022 1:12 pm
Le_Fromage_Grande wrote: Wed May 18, 2022 9:08 am That's Sunday, and a bit more than 42
Is it 43.5? Cos that sounds like free bar to me...
A free bar? Where?
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Re: Tyre pressure weirdness

Post by Horse »

Yorick wrote: Wed May 18, 2022 1:23 pm A free bar? Where?
In your patio, being stained?
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Re: Tyre pressure weirdness

Post by MrLongbeard »

Yorick wrote: Wed May 18, 2022 1:23 pm
A_morti wrote: Wed May 18, 2022 1:12 pm
Le_Fromage_Grande wrote: Wed May 18, 2022 9:08 am That's Sunday, and a bit more than 42
Is it 43.5? Cos that sounds like free bar to me...
A free bar? Where?
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Re: Tyre pressure weirdness

Post by Yorick »

MrLongbeard wrote: Wed May 18, 2022 1:46 pm
Yorick wrote: Wed May 18, 2022 1:23 pm
A_morti wrote: Wed May 18, 2022 1:12 pm

Is it 43.5? Cos that sounds like free bar to me...
A free bar? Where?
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It's not a joke if it has to explained. Still no idea
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Re: Tyre pressure weirdness

Post by Le_Fromage_Grande »

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Re: Tyre pressure weirdness

Post by weeksy »

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Re: Tyre pressure weirdness

Post by A_morti »

Yorick wrote: Wed May 18, 2022 2:07 pm It's not a joke if it has to explained. Still no idea
It was a maths joke. Or a physics joke if you squint at it a bit.
Yeh, I know...
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Re: Tyre pressure weirdness

Post by Mr. Dazzle »

A_morti wrote: Wed May 18, 2022 3:31 pm
Yorick wrote: Wed May 18, 2022 2:07 pm It's not a joke if it has to explained. Still no idea
It was a maths joke. Or a physics joke if you squint at it a bit.
Yeh, I know...
I still tell people the "two cats sat on a roof....which one slides off first?" joke, which I think I got from you in about 1998 :obscene-birdiedoublered: