Do you use dust caps?

[Ian H]

And I find I need to pump my tyres on my commuter every week or two. I always put it down to the state of London roads - but I can't really explain that statement as I accept the air has to go somewhere and, absent a puncture, I'm not sure where it disappears.

Tubes are slightly porous, yer standard butyl less so than latex. They don't contain a lot of air to start with, and it's at high pressure. Therefore only a small amount of loss will give a noticeable reduction in pressure.

 

[Archie_tect]

Tubes are slightly porous, yer standard butyl less so than latex. They don't contain a lot of air to start with, and it's at high pressure. Therefore only a small amount of loss will give a noticeable reduction in pressure.

Use nitrogen- doesn't leak as fast unless there's a sudden pressure drop....! [Costco use it]

 

[BentMikey]

I use both, but the collar nut is more important than the dust cap - it saves you putting a load on the valve/tube connection when you pump it up.

This bit is wrong, because it won't do anything to prevent valve/tube damage. It'd have to be on the other side of the rim for that to work.

 

[dodgy]

This bit is wrong, because it won't do anything to prevent valve/tube damage. It'd have to be on the other side of the rim for that to work.

It's not the first time I've heard someone mention that as a benefit of using the little collars, funny when you see their face as you explain physics to them

 

[Mr Pig]

The nut does help when pumping up. It stops the stem being pushed into the hole as you fit the pump on.

 

[Velorum]

The thought of not using them has never occurred to me.

Something else to ruminate on in the wee small hours........

 

[GrasB]

With a presta remove dust cap ride though a deep puddle, or down a river bed in my case, & leave the bike to stand for 3 or 4 days & the try to open the valve. My experience is this doesn't work. The problem isn't the water it's all the dust, mud & c**p in the water that settles on the thread.

 

[BentMikey]

The nut does help when pumping up. It stops the stem being pushed into the hole as you fit the pump on.

Aye, it can do. Not a problem on road tyres, since either the pressure is so high the valve can't be pushed in anyway, or you can just push the valve by pushing on the tyre. I guess it might be more of a pain with fat tyres like on an MTB?

I prefer to avoid having the nut on there, because if it gets overly tight it can help cause a separation between tube and valve.

 

[02GF74]

Use nitrogen- doesn't leak as fast unless there's a sudden pressure drop....! [Costco use it]

that isn't gonna make a lot of difference, air is 4/5 Nitrogen.

 

[Archie_tect]

that isn't gonna make a lot of difference, air is 4/5 Nitrogen.

Yeees, appreciate that! ...but it's the oxygen and CO2 [and inerts] making up the 1/5 that leak out that requires pumping back in, the Nitrogen molecules stay put.

I didn't think anyone would seriously cycle to their nearest Costco to take them up on it but hey, it's a wierd and wonderful world!

 

[Lazy-Commuter]

You don't still put air in your tyres do you? B)

I use helium - it's lighter. And you can do that squeaky voice thing should you need to let some back out again.

 

[GrasB]

Nitrogen in tyres is also great for keeping the tyre more stable, try nitrogen filling a car tyre & see the degrease in tyre wear & increase in cornering stability. Sure the air is 4/5 nitrogen but it's the remaining 1/5 of other stuff that causes most problems.

 

[Archie_tect]

I use helium - it's lighter.

LC you may have something there!B)

 

[Lazy-Commuter]

LC you may have something there!

Works for me!! Avoid hydrogen, though .. unless you can be sure you'll never go over a lit cigarette thrown into the road!!

 

[Archie_tect]

Works for me!! Avoid hydrogen, though .. unless you can be sure you'll never go over a lit cigarette thrown into the road!!

You'd only do it the once....