Any question answered...

no doubt

yes

How can you make chilblains go away? (fuck you, spring...)

Wicked.

^^ special brew

Is it possible to pop a tube by overheating your rims?

I got a sudden front flat today, near the bottom of an absolutely horrendous descent. Super steep, narrow, with lots of switchbacks and a really bad road surface which meant I had to ride the brakes a lot. The tube gave suddenly with an audible hiss and when I checked it, there was nothing obvious stuck in the tyre, no bulges, no problem inside the rim and the hole on the tube was more like a 3-4mm split, on the side where it would be closest to the brake track. I was running 115-120psi so it's unlikely to be a pinch flat and there's only the one large hole anyway, no snakebite. Tube was seated properly (I checked when I fitted it) and I'd put nearly 100km on it today before this with no problem, and countless km before that.

When I came to remove the tyre I had to give the rims a few minutes to cool down because, hot damn!

Did I ride a route so gnarly it exploded my tyre? :)

Yes, latex inner tubes are not recommended for use with carbon clinchers for this reason.

Q
anyone know if there is enough spare (5mm) axle on a factory R500 wheel to fit with spacers in 135mm dropouts?

I have one with 27.0 and another 27.2

What size seatpost will a Reynolds 501 frame take?

Q
anyone know if there is enough spare (5mm) axle on a factory R500 wheel to fit with spacers in 135mm dropouts?

No, the axle is 138mm like all Shimano road rears. You can easily put a 146mm MTB axle in there though, the axle is £13.99 or less, but you'd be better spending ~£20 on a complete FH-M525 or similar hub as that will get you the longer QR skewer too.

thank you very much indeed

Yes, latex inner tubes are not recommended for use with carbon clinchers for this reason.

I'm running standard butyl Vittoria Ultralites, but good to know.

FWIW latex tubes would be fine in your wheels, as IIRC they're planet x clinchers with an aluminium rim and carbon fairing?

Don't forget he live where it can be stupidly hot at time.

Yes and yes (up to 40C in summer, ugh).

I had to ride the brakes a lot.

No offence .. but you need to brake better! You need to learn to jump on the brakes to the point of the rear lifting off the ground and release when the speed is scrubbed off .. This allows the rim to dissipate the heat to the air between braking efforts.

To be honest, check you haven't melted you brake pads too

And I can tell from your post that you're also changing gear at the wrong time and leaning too much.

^^BS. The bike has the same kinetic energy regardless of how you brake. The Ek is transferred into heat. Surely the longer the 'transfer time' of the energy, then the more the rim will be able to cool down while braking? Transferring all the energy in one burst means that the rim won't really cool while braking, and so would get hotter?

Please correct me if my ALevel physics is letting me down.

Doubt it matters too much, if fancy giant DH rotors with air cooling vents and whatnot overheat at times then it's reasonable to assume that rim brakes that probably haven't been designed to get rid of heat to the same extent might overheat occasionally. You were probably pedaling in a wonky fashion too.

^^ I don't disagree about the amount of energy put into the rim being the same.

Where I do disagree is if you place all the energy in one 'short burst' the temperature difference between the hot rim and ambient air is greater so the heat transfer to the air will be greater. Ie. the 'short burst' will cool rapidily and since you are not on the brakes the rim will continue cooling between braking applications ..

I s'pose so...

Braking should brief and hard.

I thought you were breklez.

caught out mo-fo.

Also if the temperature difference is greater between the rim and the air, you are saying the rim is hotter, is that not more likely to damage a tube? Or is the not quite as hot but hot for longer more likely to damage a tube? Maybe if he didn't wear inappropriate clothing it wouldn't happen.

Is there anywhere or anyone selling a white romin saddle in 143mm for less than £50?