Any question answered...

CO2 is a smaller molecule than N2, so it leaks out quicker.

You fail at physics, but the explanation for the fast leakage of carbon dioxide turns out to be a question of chemistry. If it were simple gas physics, the big CO2 molecule should leak slower than the smaller N2 molecule, and so it would through any other barrier. Unfortunately for cyclists, CO2 goes through butyl rubber very easily because the one is a solvent for the other - I can't remember which way round, and I'm not about to get sidetracked while I should be working.

You fail at physics, but the explanation for the fast leakage of carbon dioxide turns out to be a question of chemistry. If it were simple gas physics, the big CO2 molecule should leak slower than the smaller N2 molecule, and so it would through any other barrier. Unfortunately for cyclists, CO2 goes through butyl rubber very easily because the one is a solvent for the other - I can't remember which way round, and I'm not about to get sidetracked while I should be working.

Oh come on, you could have left that for a while. I liked the idea of 2 nitrogen molecules being bigger than a carbon molecule and 2 oxygen molecules.

Oh come on, you could have left that for a while. I liked the idea of 2 nitrogen atom being bigger than a carbon atom and 2 oxygen atom.

ftfy

I was trying to compare two non-equivalent measurements from wikipedia data tables.

Meh.

They look like new designs actually, blue and white logos rather than the red and yellow. Matches my bike better, but still.

I'll call the distributor from work tomorrow so I've got more ammo for Cycle Sports UK if they've done me over.

Zyro say PT > TG and that the ones I have are the latest and greatest.

Bargain.

ftfy

I was trying to compare two non-equivalent measurements from wikipedia data tables.

Meh.

Wiki fail? Can't I have my piss take too?

Who knows what make these sunglasses are?

The distinguishing feature is the little metal shape inset into the arm, I bought this pair on holiday and cannot for the life of me remember the make.

They went AWOL on a stag do a few years ago, and I'd like to replace them.

May help with identification.

http://www.youtube.com/watch?v=Vxq9yj2pVWk

looks like cébé to me.

Rep to you sir.

I reckon these are the closest:

Should have bought two.

I was trying to compare two non-equivalent measurements from wikipedia data tables.

It turns out that if you were just looking at notional molecular diameter, you probably called it right, although if you were thinking of Graham's Law, it's molecular mass that matters.

Either way, the problem is that CO2 dissolves in rubber much more easily than do the other gases under examination:
http://www.madsci.org/posts/archives/may98/895552329.Ch.r.html

After posting, I wondered what you would use instead; a nice big, heavy, inert (non-reactive, non-polarised) molecule, and obviously SF6 was the first thing which sprung to mind. So, assuming you're riding a 24h TT, would the time saved by not having to re-inflate/having consistent rolling resistance be more than the time lost through having an extra 120g of gas in your tyres?

[ame=http://www.youtube.com/watch?v=DzLX96VWTkc]http://www.youtube.com/watch?v=DzLX96VWTkc[/ame
]

Anyone in NW/West that can let me use some untaped spotter bars to test lever positions with DA 7402s this weekend?

http://www.ebay.co.uk/itm/Sugino-Bottom-Bracket-Cups-Lockring-Bearings-French-Thread-35-x-1-NOS-/380525414214?pt=LH_DefaultDomain_0&hash=item5899150746&_uhb=1

Do we think this would fit a modern sugino 75 axle?

So what's the name of this magic sf6 gas?

It's named (in American) in the accompanying YouTube clip, but for English readers it's Sulphur Hexafluoride

Some people have used SF6 in speaker cabinets to improve the behaviour of the cone. I didn't understand it all but it seemed like unnecessary hassle.

Ah but tester, I have the volume off so as not to wake my housemates further!

But it is a curious gas. Google says lots. Thank you pregoogleman.

It would be fun to secretly fill other people's tyres with SF6 at weight-weenie contests :-)

What's happened to young xander these days? says he hasn't been on the site since october...

What's happened to young xander these days? says he hasn't been on the site since october...

He's changed his username and become an anonymous misogynist, until outed by Velocio, IIRC.

Any recommendations for products I should use for cleaning an old frame? Paintwork is ok, but could do with being freshened up a little, and there are spots of rust stain and crap that need to be cleaned up.

What should I use? Get a TCut of the right colour - that will freshen (read: take off the top layer) of the paint. But does it clean rust stains?

Any better recommendations?

Get a TCut of the right colour - that will freshen (read: take off the top layer) of the lacquer.

ftfy.

But does it clean rust stains?

No.