Just Sitting in my Room, Heard a Big PSSSSSSSSSSSSSS

Thargor

And I open the door onto the landing where I keep my bike and the valve on my front tyre is just letting all its air go, the valve cap is still on tight and I haven't been on it in 2 days! WTF just happened?

Home:Ballyhoura

Is it near a radiator? Often the air in the tube expands with the heat and goes bang but probably not if yours went psssss and not pop!!

Thargor

Nope, and the house is freezing, this friggin sucks, Im supposed to cycle from Bray to Greystones tomorrow after work with some people and now Im going to look like a dick making excuses, I swore after my last flat I was going to have spare valves and stuff ready and I never bothered, b0lllox!

LCRC_BAX

you could get a new tube tomorrow & change it!

Thargor

Our industrial estate is in the middle of nowhere and we work until 6pm, gah, I think Ill keep my old bike just to have a spare in this situation after I do the CycletoWork scheme, a flat really does ruin everything.

DirkVoodoo

No spare tube? What would have happened if this had happened on some remote road around Wicklow?

Punctures aside, the valve-tube interface is probably the weak link in the design, it's not entirely uncommon.

I'd just be glad it didn't happen on the aforementioned remote road.

petethedrummer

A spare bike in case of puncture? Hows about a puncture repair kit?

blorg

The sides of the hole in the rim can pinch the tube at the valve causing a puncture. This type of puncture is unpatchable (needs a new tube.) It will also often hold air fine for a while but it will come out depending on the position of the valve. It happens a fair bit to me reinflating with a mini or frame pump; much less likely to be an issue with a track pump. I sometimes add a bit of insulating tape around the hole if the edges are rough.

frant2

anyone know if tubes fixed with repair kit are ok to use at 100+ psi? - Austerity measures an all that - I used to carry new spare tubes, now Ive patched ones.

seamus

frant2 wrote: »

anyone know if tubes fixed with repair kit are ok to use at 100+ psi? - Austerity measures an all that - I used to carry new spare tubes, now Ive patched ones.

Yep, a properly patched tube should have no difficulties at these pressures. I find road tubes much more stable when patched (compared to MTB tubes), probably because they don't stretch very much when inflated.

I would still carry at least one spare tube just in case you end up with an unfixable puncture

Keep_Her_Lit

Home:Ballyhoura wrote: »

Is it near a radiator? Often the air in the tube expands with the heat and goes bang but probably not if yours went psssss and not pop!!

That reminds me of why the wear indicators on wheel rims shouldn't be ignored, i.e. those tiny little dimples that can be seen on the braking surface of a new rim and which are eventually worn away by rim brakes.

Someone I know (not me, another cheapskate) parked his bike up against a radiator after a hard day's couriering. Sometime later, there was a sudden and violent bang from the bike.

Inspection revealed that the rim had split, along the braking surface, about half way around the wheel circumference, causing the tube to rupture instantly. That was a lucky escape, since fairly soon it would have happened out on the road, in traffic instead.

Keep_Her_Lit

blorg wrote: »

The sides of the hole in the rim can pinch the tube at the valve causing a puncture. This type of puncture is unpatchable (needs a new tube.) It will also often hold air fine for a while but it will come out depending on the position of the valve. It happens a fair bit to me reinflating with a mini or frame pump; much less likely to be an issue with a track pump. I sometimes add a bit of insulating tape around the hole if the edges are rough.

Good tip, thanks. I've fallen foul of that a couple of times. As you say, not a problem when a track pump is available. The problem with mini pumps is that they can't be held perfectly still, especially as the tyre pressure increases and more force is needed. So the wheel gets jolted around, with the force being transmitted through the valve stem.

When fixing roadside punctures I find it helps to avoid this type of puncture by inflating the wheel on its own, rather than after replacing it on the bike. Being reasonably light, relative to the bike as a whole, the wheel can bob around a bit without putting too much stress on the valve.

Keep_Her_Lit

seamus wrote: »

I would still carry at least one spare tube just in case you end up with an unfixable puncture

Definitely. But always remember to find the pesky piece of glass or whatever caused the puncture and remove it from the tyre before fitting the new tube. Finding that you only manage to travel a few hundred metres after your "repair" before you once again hear that " pffft ... pffft ... pffft ..." is a great way of learning this lesson the hard way.

After removing the punctured tube, I reinflate it to a low pressure, find the "hissssss" and then align the tube with the wheel/tyre to get the approximate location of the offending item. Sometimes you have to look quite hard to find it. The tiniest shards of glass can worm their way right into the tyre, so that they aren't readily spotted on the surface.

Another advantage of carrying a spare is that on a cold, dark, wet, windy winter's night, fitting a fresh tube is a whole lot nicer than trying to successfully patch a punctured one.

el tel

Too late now but what about replacing the deflated tube with one from 'the old bike'?