sods law puntures and tyre pressures

tired legs

hi all went for first ride on brand new cycle ,got about six miles from home and stopped for a rest, looked down and front tire was flat, tried pump to no availe.

a while later whilst pushing cycle along towpath , a cyclist seeing my plight, very kindly repaired my puncture, and off i went stopped a mile or so later and thought tire seems a bit underinflated, so out with pump and the (pump connecting hose broke. tire was completly flat .
so pushed cycle home , mostly uphill .


reinflated tube , immersed it in water no leaks.

never realised cycle tyre pressures needed to be so high 50 psi min for my cycle/tyres, deflated tyre, gave it 20 stokes of pump measured with car tyre guage it was 28psi,

so gave another 20 pumps assuming the pressure would be approx 55 psi and guage read 29psi???? are there specialised pumps/gauges for cycles

ps on the way home tried inflating tube with a garage tyre pump , but it did not inflate (shrader valve) so suspected valve might be faulty seemed of at immersed in water.

in future i think it might be wise for me to carry a spare tube,

thanks all

alfeng

I believe that the CORE of a Schrader valve can be replaced ... a bobbie-pin should be all that you need ...

You can probably get a freebie if you ask your local tire dealer for a stem that has been pulled from wheel which is getting a new tire ...

BRING THE TUBE WITH YOU because the tire dealer may swap the "used" core for your bad core in your tube as a goodwill courtesy (well, that would be a smart business move).

FWIW. The SPRING in the Schrader core may simply be "stuck" in a bad way ... you may be able to manipulate it with a little poking-and-proding.

butchh

+1

I have actually had schrader valves release air at speed on my motorcycle. Not a fun experience at 70+mph. Replace the valve core. If this doesn't work, replace the tube.

tired legs

hi took wheel back to dealer, they could not find any obvious leak in tube.or anything on inside of tyre , so i pointed out that the valve was proberbly suspect.

they replaced tube with slime type tube with presto valve FREE OF CHARGE



butch tyre deflating at 70 mph must have been a bit unnerving .

thanks all

alfeng

Glad to hear that your LBS replaced the tube "free of charge."

As you can see, the NEW, Presta valve stem has a smaller diameter ... it is VERY important that your shop's "mechanic" put a grommet in the rim's valve hole to make up the difference otherwise the valve stem may be damaged while riding the bike.

More importantly, because your tube has SLIME -- I have found this to be true with ANY tire that has sealant -- you want to park the bike with the valve stems at 12 o'clock ... because, even though the tire is now flat resistant, you will be putting air in it from time to time.

Your pump may-or-may-not have a Presta to Schrader adapter ... if your pump has one, it will be about the size of a Schrader stem cap & nestled in some nook-or-cranny on the pump. If you can't find such a "creature" then you may need to buy one.

To state what may be all too obvious -- as a matter of convenience, it is better if the tubes on both the front & rear wheels have the same type of valves (but, it isn't critical) ...

tired legs

thanks alfeng no grommet was fitted to take up differance in valve diameter, i purchased another slime tube for rear cycle tyre , so that valves etc would be the same ,

however the one thing that really puzzles me is,

old halfords cycle 26" wheels /presto valves never had any trouble pumping up tyres so they felt hard to the touch using bog standard plastic long cycle pump.

in the cycle shop they have big floorstanding pumps they use to inflate tyres.

yesterday fitted tube to rear wheel ,and regardless of how many pump strokes i use i cannot inflate tyre so it feels as hard as the front one , i cannot see my new tyres being 700c size vs 26" making any differance.

the tyres are so called puncture resistant types, so i can only assume they might be a bit tougher tyre walls on inspection of tube/tyre with puncture could not say there was an obvious differance in thickness that i could tell .

tyres should be 50 min 85 max

thank you

alfeng

I think this is ANOTHER case of a "bad" valve which is making it difficult to transfer air from the pump to the tube -- a partially "sealed" valve caused by the sealant!

You can try to remove the core to clean out the stem -- SLIME has fibers suspended in the green goop which forms a felt-like fabric plug in OPENINGS (e.g., punctures ... your valve!) when the goop dries.

I've seen SOME Presta valves where the core cannot be removed; but, I presume that tubes which have sealant will have a removable core.

Of course (and, this is the option I would probably choose), you can trundle back to your dealer and get them to exchange the faulty tube with a replacement tube since the tube in question was clearly "bad" from the get-go ...

tired legs

thanks alfeng i believe you may be correct re valve presto core does not seem to be removable (no flats)


purchased yesterday cheapo vento track pump from local willkinsons, largish floorstanding type. 3 pumps and tire was hard some hours later tyre was slightly deflated with some green slime around presto valve just cant believe my luck possible 2 faulty valves in one week

thank you

gclark8

My Conti Tubes have removable Presta Valves.

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Cheers,
George.