Paul Green said:Ok I am new to road bikes, so my question might sound a little silly, but
please give us a fair go.
Ok I have noticed on my new road bike that the Valve stem on the rear tyre
is shorter than the one on the front, is this normal ?
Secondly, I am a heavy weight at 85kg's, and I like to keep my tyres
inflated to around 120kpi's as advised by my bike shop.
Ok I bought a good quality foot pump Serfras Brand.
I try to keep my tyres at around 120, however when I put the pump on the
stem, and start pumping at around 110, its keeps shooting off the stem, why
??
Also with the presta valve, should I undo it a little , give it a tap to
break the seal, then pump it up ? is this the correct way ?
Thanks guys for any answers, even though to you seasoned pro's these
questions might sound silly,
Thanks again.
No, I'm sorry, you're suffering from SHRINKING VALVE STEM SYNDROME and should take it to your local branch of Bob's Bicycles AS SOON AS POSSIBLE and have them do a valvectomy on the wheel. The screams are hard to bear if you do it yourself.
Secondly, kpi's are an old and outdated form of pressure measurement, not much favoured by us "seasoned pros" any more, due to fact that the Kangaroos are quite loath to remain on the specified Inch whist the pressure is checked, having an inbred racial memory of unpleasant exploding sensations when they were unskillfully utilised in the past for such purposes.
Thirdly, it may appear to be a tap on a valve nut to us, but to the valve, proportionally, it would feel like having a piano dropped on it. So be kind to your hard-working valve nuts, and PRESS them, and they will reward you with many kilometres of unwavering and faithful service.
Fourthly, the Serfas pump you have bought obviously has deep issues with certain brands of valves. It is equivalent to racism in humans. You must educate it that Continental valves, even tho' they have replaceable inners, are just as worthy as Vredestien, or even Cheng Shin valvestems, and that it should see each one as having a role to play in the Great Whole that is Inflation. It may be hard work, but in the end, it is worth it.
😉
Seriously, there are 3 or 4 lengths of valvestem - one is appropriate for your rim. Just enough sticking out for a pump chuck to grab onto, not enough to rattle around too much. Don't get stressed - just change it for the appropriate length when you have your next puncture.
You're right about the valves. Break the seal before attempting to inflate with a small tap (or press 😉 )
Check the rubber in the pump chuck (bit which grabs the valves) for fraying/displacement. You may be able to tighten the collar holding the rubber in the chuck for a better grip. Make sure you have the lever on the chuck in the right position when pumping (refer instructions/knowledgeable "seasoned pro" ). A lot of pumps have this prob. Get a friend to hold the chuck on whilst pumping if necessary.
Hope the second bit helps
M"pounds/KiloPascals/Bar - the last sounds a bit saucy vis a vis pumping" H
