Anybody else not checked tyre pressures for a while?

[Wicky]

For track use you remove air and pump in more vacuum to keep tires from conducting heat and overheating.

For road use seaside air is best as it contains negative ions that have the ability to absorb extra oxygen and thus aid the tires to breathe better.

[Diabolus]

i check mine every two weeks at least with the digital pressure gauge,

some might think thats anal i don't know i just like to have peace of mind and top up if required

same here

[Xenocide]

I went out and thought "this is a bit squidgy", sure enough, pressures way down.

I won't tell you what they were but let's just say i really should have checked beforehand .

Feels bloody lovely now though.

[Pete.L]

Would fitting a stronger valve spring reduce air loss? I was watching something other day and they said at speed the inertial forces on the spring can cause it to back off and a tiny amount of air escape

Sent from my GT-I9300 using Tapatalk 2[/quote]


The valve is pushed IN to let air escape, so centripetal force will push it shut not open.[/quote]

centripetal??? yes, that will be applied by the spring to close the valve but
i think Centrifugal forces are what Seb is talking about, over powering the spring:lol:
Good question Seb, and It's certainly possible. Contrary to what Matty thinks the central pin could get heavy enough to release air or nitrogen for that matter. The weight of the pin versus the strength of the spring also the internal pressure of the tyre and the speed of rotation would all have to be taken into consideration. I've only heard of it being an issue with high speed racing cars but I don't see why it couldn't transpose to road vehicles too
Maybe we should set up some tests?
I know some good stretches of the A38 we could try

Pete.l

[Whoa Nelly]

Just use nitrous; you'll be laughing.

[Kev L]

Just use nitrous; you'll be laughing.

Ba boom tish!!

[mattycoops43]

Would fitting a stronger valve spring reduce air loss? I was watching something other day and they said at speed the inertial forces on the spring can cause it to back off and a tiny amount of air escape

Sent from my GT-I9300 using Tapatalk 2

The valve is pushed IN to let air escape, so centripetal force will push it shut not open.[/quote]

centripetal??? yes, that will be applied by the spring to close the valve but
i think Centrifugal forces are what Seb is talking about, over powering the spring:lol:
Good question Seb, and It's certainly possible. Contrary to what Matty thinks the central pin could get heavy enough to release air or nitrogen for that matter. The weight of the pin versus the strength of the spring also the internal pressure of the tyre and the speed of rotation would all have to be taken into consideration. I've only heard of it being an issue with high speed racing cars but I don't see why it couldn't transpose to road vehicles too
Maybe we should set up some tests?
I know some good stretches of the A38 we could try

Pete.l[/quote]


Not sure I am following this, centripetal force is the outwards force, which would be acting to push parts of the valve away from the axle. Centrifugal is the inward restraining force that stops the parts being flung outwards, they cancel each other out unless a part is actually moving in or out.

I am quite happy to admit though that I was getting it butt about tit though as yes, the centripetal force would be pushing the valve down into the wheel rim so releasing air, however it is a factor of the weight of the valve centre, so as it's probably about 1gram it would be a tiny amount of force.

Hmmm, maybe lightweight, titanium race valve centres are the way to go!

[Pete.L]

Umm! Titanium....That's got to be the answer, either that or carbon fibre

[Kev L]

Umm! Titanium....That's got to be the answer, either that or carbon fibre

Hmmmmmmmmmmmmmmmm Carbon & Ti, oops just had a crisis!!!!

[AMCQ46]

or use 90deg bend valves so they are easy to inflate at the petrol station and the centripetal force [good to see someone that knows what that is ] is no longer acting in the direction of the valve & spring..............Then fit Ti caps just for fun

[Flatline]

Could you use Helium in the tyres, to lighten the bike?

Would be cheaper than carbon wheels etc

[VTRDark]

Could you use Helium in the tyres, to lighten the bike?

Would be cheaper than carbon wheels etc

I like that idea. It would make the fly

(:-})