Friday, January 11, 2008

"I think it's my pump, doctor..."

A little while ago I posted about a valve that I managed to pull from a tyre.

Well, I did it again on wednesday night.

I started out for a light half-hour or so breeze on one of my bikes after changing to a set of wheels that normally resides on my Sunday morning group road bike. Long story, there's two bikes and six wheels. They'd been sitting unused for a couple of weeks, and I forgot to check the tyre pressures before I went. I rode no more than a kilometre when I realise the back is down a little. No problem, I've got a pump on the bike, I can get it to 80PSI, enough for a quick ride.

Clip it on, flip the lever, start pumping. Something is wrong, oh so terribly wrong.

The tyre is inflating, slowly, but each time I stop it deflates just as slowly. Out via the valve. Unclip the pump to see that the head has actually bent the valve end and spindle that pokes out from the main valve body. Therefore, if you try and do it up, it deflates itself.

Picture (C)

Yes, it SHOULD be straight, but it wasn't. More like 6 degrees of bend.

I limp home, reflecting that its been a recurring theme on this particular bike...limping at the end of Sydney Gong, limping home twice now. I use a pair of pliers to straighten the spindle. I put 100PSI in with the floor pump, and off I go. 40 minute ride without trouble.

Next morning, I glance into the garage to see the back tyre sitting pretty on the ground, somewhat spread. Again, no worries, I'll just hit it with the floor pump and get it back, leave the valve cap off and she'll be right, right?

Er, no. Every pump in equals a large hissing out. Its about then I realise that this valve has broken away from the tyre as well. Lucky it didnt happen on the road, but what would've done it? Pull it out last night after I got home from work, and sure enough the valve stem has ripped halfway around at the base.

The only thing consitent thing in both these has been the pump. It seems to take a fair bit of force to get it on, and it really rocks when you push it. I'll check the head is on the right way, but I'm sure it is. If so, then its not getting used again on road tyres, I'll save it for my mountain bike once I get it rebuilt and ready to roll. At least I can change the head to fit the schraders on the 26" wheels.

I dont think I'll use the little knurled rings on valves for a while either, till I see if that might be my problem. How tight should they be, after all? Too loose and they vibrate down and rattle. Too tight and it seems they assist in pulling tyres apart.

To top it all off, the back wheel on my road bike spontaneously burst last night out of the blue. I ripped the tube out, despite the late hour, to find a pinch flat not far from the valve. I'd had it trued five days ago, so I guess its been biding its time till now. Maybe it was the temperature rise that killed it. I dont think I can repair it, its too close to the stem. Its replaced now anyway, and Sunday will be a test to see if I get through without popping another one.

Just when you thought it couldn't get funnier, and to bring my 'bad luck in threes' back to reality, my rear 'commuter' wheel seem to have a problem at a spoke hole giving me a flat two weeks ago. Thats #3 for now. Let this be the end, please...

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