It's not been a good week :-(
Tuesday evening. All sorts of things at work so I'm very late out. Get
outside, unfold the brompton, lift and spin the front wheel to check the
lights, nothing. Wiggle the cables etc, still nothing. Then I notice the
rear light is on. Front bulb gone. Get out spare bulb. Check again. All
looks good. Set off for the station.
Just as I'm about to turn right off the Euston road to Euston.
Pssssssssss. Front puncture. Push the bike to Euston. Still manage to
get my train. Replace innertube on train.
Cycle home, pull into my drive. As I come to a stop "hmmm that's funny,
standlight isn't working". I obviously hadn't switched the lights off
Tuesday morning and I've destroyed the front standlight. (FWIW this
proves that two back to back 8v1 zener diodes[1] won't protect a lumotec
front light but will protect a rear standlight - think it's B&M)
Cycle to the station Wednesday morning. Just pull up at the station.
Psssssssssss. Another puncture. I've also forgotten to put a new spare
tube in my bag so I'm still carrying the punctured one. Push the bike
home. Now it's daylight and I can see properly I realise that the brakes
are just rubbing on the tyre at one spot and have worn a tiny hole where
the innertube is poking through. So put spare tyre on bike and another
innertube and adjust the brakes. Buy a new kevlar tyre and innertube and
plan to swap the "spare tyre" which isn't kevlar at the weekend.
Thursday, nothing too eventful until I get to my home station and unfold
the bike to go home. Rear tyre is a bit flat. I've obviously got a slow
puncture in the rear wheel now. Manage to get home although it's
starting to feel a bit unsteady. Thursday night do a big puncture repair
session on the four or five innertubes that I've been waiting for some
Round Tuits to fix. (It's actually easier reparing lots of innertubes in
one go I've discovered as you aren't sitting around waiting for the glue
to dry and you aren't tempted to stick the patch on too soon because you
are preparing the next tube while the first one is drying)
Today, nothing too eventful until I unfold the bike to set off to
Euston. Front tyre is completely flat. Change innertube and cycle to
Euston. On the train pump up the bad innertube but I can't find the
puncture. At home tonight put the innertube under water and find that
the puncture is almost at the top of the valve stem (nearest where the
pump attaches). I have no idea how I can have got a puncture there that
managed to keep the tyre absolutely solid from Wednesday morning to
Friday night. (I could understand damaging it there while pushing it
through the rim or possibly even pumping it up but otherwise I can't
imagine what I've done)
Finally get home to find that the stuff from 7dayshop has arrived.
Unfortunately I discover that I've ordered the wrong part for one thing
so that will have to go back. Still there's some other stuff on their
website that I'd like but couldn't really justify when I did my order so
perhaps they'll do an exchange rather than a refund. And then I can buy
the stuff I need from somewhere else :-)
Tim.
[1] I'd hoped that this would be ok. This would start clamping when the
voltage reached about 6V RMS (and indeed I can just see the clamping on
the oscilloscope at 20kph - which is about the maximum speed I can spin
the wheel) but would mean that the voltage can rise as high as ~9V RMS
(I'm assuming .7V forward voltage drop - I don't know if that's
reasonable or not for a zener)
--
God said, "div D = rho, div B = 0, curl E = - @B/@t, curl H = J + @D/@t,"
and there was light.