Tyre pressure weirdness

[Count Steer]

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

Punchline?

[Mr. Dazzle]

The one with the smallest mu!

[A_morti]

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

Was that definitely me? I just had to look up "mu".

[Mr. Dazzle]

I dunno, 1998 was a long time ago

[Supermofo]

Me too!!!

Just checked my rear pressure as tyre bloke set it to 42 and I want to use the bike tomorrow so want to make sure all is good with the puncture repair. Stick my Halfords footpump on and....50psi. Hmmmm. Check the front and 42psi.

Given matey checked the rear a couple of times at 42 and then checked the front was right too I can only imagine my foot pump is well out. Either that or I'll be riding on balloon tyres tomorrow.

[Skub]

Me too!!!

Just checked my rear pressure as tyre bloke set it to 42 and I want to use the bike tomorrow so want to make sure all is good with the puncture repair. Stick my Halfords footpump on and....50psi. Hmmmm. Check the front and 42psi.

Given matey checked the rear a couple of times at 42 and then checked the front was right too I can only imagine my foot pump is well out. Either that or I'll be riding on balloon tyres tomorrow.

Maybe the tyre dude gauge wasn't calibrated.

[Supermofo]

Me too!!!

Just checked my rear pressure as tyre bloke set it to 42 and I want to use the bike tomorrow so want to make sure all is good with the puncture repair. Stick my Halfords footpump on and....50psi. Hmmmm. Check the front and 42psi.

Given matey checked the rear a couple of times at 42 and then checked the front was right too I can only imagine my foot pump is well out. Either that or I'll be riding on balloon tyres tomorrow.

Maybe the tyre dude gauge wasn't calibrated.

If that was the case the front wouldn't be 42, he didn't put any air in that just checked it. It was 36 last time I checked it a few weeks back

[Le_Fromage_Grande]

Mine was 38 when I got home from work

[Supermofo]

Found my old pencil gauge that came with the track bike. Bitch to get a seal but 50 on the pump was just over 40 on the gauge on the rear.
On the front was really difficult to get a seal but at 42 on the pump I finally got a seal at 35 on the gauge.
So looks like my pump gauge is shite. Probably why I found running my 690 at higher pressures felt better!!

Wonder if I get one of these.



https://www.sportsbikeshop.co.uk/motorc ... rod/497461

[weeksy]

https://www.decathlon.co.uk/p/airchecke ... lsrc=aw.ds

I've got 3 digital ones for MTB racing. They all register the same, but the SKS is nicest and easiest

[wull]

This is my go to pressure gauge, used it for years with the race bikes and track bike. I’ve got various other ones but they’ve managed to find their way to work so this one along with a track pump have stayed at home.

https://www.venhill.co.uk/tyre-pressure ... -vt32.html

[Supermofo]

This is my go to pressure gauge, used it for years with the race bikes and track bike. I’ve got various other ones but they’ve managed to find their way to work so this one along with a track pump have stayed at home.

https://www.venhill.co.uk/tyre-pressure ... -vt32.html

Seem to recall reading they are good

[KungFooBob]

I've got one of these, I bought from B&Q years ago...



I've got a digital Halfrauds one too.

Both ready pretty much the same, which is always a good 5psi different to the gauge on the footpump.

[wull]

This is my go to pressure gauge, used it for years with the race bikes and track bike. I’ve got various other ones but they’ve managed to find their way to work so this one along with a track pump have stayed at home.

https://www.venhill.co.uk/tyre-pressure ... -vt32.html

Seem to recall reading they are good

I’ve been looking at the MotionPro digital pressure gauge recently as it’s very accurate but very pricey. Do we really need the accuracy? I don’t think so. I think for the price of the Venhill you can’t go wrong.

[Dodgy69]

I've never gone by the pump gauge, always used a separate gauge. 2 reasons,
don't trust them,
can't see them.

[wull]

I've never gone by the pump gauge, always used a separate gauge. 2 reasons,
don't trust them,
can't see them.

Exactly what I do, use track pump to adjust (add more) and use gauge to take an accurate reading.

[Supermofo]

I've never gone by the pump gauge, always used a separate gauge. 2 reasons,
don't trust them,
can't see them.

My downfall I think is my old foot pump was pretty good when compared to other gauges, so I assumed this one was too. And looks like I'm wrong!!

[The Spin Doctor]

The tyre itself will expand

When it's static?

There's a very strong belt around the tyre which is designed to prevent tyre growth when rotating at high speed, so I would be very surprised if any significant thermal expansion in the tyre itself happened, and I'd suggest it is 'not detectable' with a standard tyre pressure gauge anyway.

I agree, 99.99% certainty it's down to the pressure gauge not giving accurate readings. Occam's Razor. If you need an explanation, look for the simplest.

[dern]

I use a Draper 69924, the flexible hose makes it easy to use on all bikes but the wheel with side exit valves are the easiest.

I've also got a RACE X RX0014 as a spare but they both read the same.

I use the pump gauge as others have said, to inflate past the point I want and then deflate to where I want it.

[Mr. Dazzle]

The tyre itself will expand

When it's static?

There's a very strong belt around the tyre which is designed to prevent tyre growth when rotating at high speed, so I would be very surprised if any significant thermal expansion in the tyre itself happened, and I'd suggest it is 'not detectable' with a standard tyre pressure gauge anyway.

I agree, 99.99% certainty it's down to the pressure gauge not giving accurate readings. Occam's Razor. If you need an explanation, look for the simplest.

Pretty much everything expands when it gets hot (carbon fibres don't!). Just not very much

I reckon it's an issue with the gauge though too.