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Tyre valve attachment?


goat
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IMG_2556.jpg


What be this? One screwed on each tyre valve (tubed tyres). Have taken off for Checking and topping up pressure, struggling to get a consistent reading on the rear tyre for some reason. Pumping up with cheap foot pump, checking pressure with a

Race x pressure Gauge. Access is awkward and no pffft of air when putting Gauge on valve.

Thought the attachment might be a Schrader to presta converter but looks different and no idea why you would put one on anyway.

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Would agree muchly.......only thing is, don't leave them attached to the wheel all the time....no, really! :D


Once met a guy complaining about wheel wobble, pattering at speed (IIRC it was a Suzi X7....and those X7s were fast for the time.....if you had enough pairs of Y-fronts) and general handling crap - had a look at his bike only to find 2 of those beauties proudly mounted on the rims :shock: !


Subsequent removal led to the prompt restoration of handling sensibleness.....

Edited by Anonymous
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Would agree muchly.......only thing is, don't leave them attached to the wheel all the time....no, really! :D


Once met a guy complaining about wheel wobble, pattering at speed (IIRC it was a Suzi X7....and those X7s were fast for the time.....if you had enough pairs of Y-fronts) and general handling crap - had a look at his bike only to find 2 of those beauties proudly mounted on the rims :shock: !


Subsequent removal led to the prompt restoration of handling sensibleness.....

 

Simple fix is to have the wheel balancing carried out with the extensions fitted! 8-)

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Would agree muchly.......only thing is, don't leave them attached to the wheel all the time....no, really! :D


Once met a guy complaining about wheel wobble, pattering at speed (IIRC it was a Suzi X7....and those X7s were fast for the time.....if you had enough pairs of Y-fronts) and general handling crap - had a look at his bike only to find 2 of those beauties proudly mounted on the rims :shock: !


Subsequent removal led to the prompt restoration of handling sensibleness.....

 

Simple fix is to have the wheel balancing carried out with the extensions fitted! 8-)

 

......yes, but that would involve a process called "thinking"...... :mrgreen:

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Why have an extension? Just get a right angle valve.


http://preview.ibb.co/fjLoaG/20140516_091919_zpsdf1b12d4.jpg

Hi Rae, where did you get yours? Seem to be available easily enough on the bay - do tyre fitters supply them as well? They would seem like a good idea - anybody had any problems with 'em? Only con I can think of is that these days, tyre valves seem to be treated as a disposable - changed with the tyre. If you're paying up to £16 a set, some people might be tempted to hang on to them longer than is appropriate?

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The one you see in the picture was on my BMW K1200 GT fitted by my tyre place about £6/7 I have black ones on my FJR also fitted by my tyre place as I have black wheels. They make life so much easier when inflating the tyres, I also use tyre sealant and they make putting that in easier too.


They are a permanent fixture, mine have been on since I had my first tyre change. I suppose you can change the schrader valve if you felt the need with the OPs valve cap. :D

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Does this help?


......While centripetal force is an actual force, centrifugal force is defined as an apparent force. In other words, when twirling a mass on a string, the string exerts an inward centripetal force on the mass, while mass appears to exert an outward force on the string.

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We had this discussion at uni the other day. :-) Bloody ages it took too!


If a wheel is spinning then centripetal force is essentially the tension in the spokes which prevents the rim flinging off in to the distance. Centrifugal force acts in the opposite direction i.e. outwards to counter the inward centripetal force of the spokes.

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So what force causes the tyre valve to get ripped out and why?

 

Centrifugal.


As the wheel spins, the force acting on the valve is in an outwards direction. As the wheel speed increases, so does the centrifugal force (g) to a point where it overcomes the rubbery bit and the metal bit moves towards the rim. High enough wheel speed will give enough centrifugal force to exceed the shear limit of the rubber and off it goes.


The force is quite large - if you consider those spinny things used in astronaut training - the person gets quite badly squashed down and pass out under single digit g. Assuming a 17" rim and a 10 gram valve, your valve will undergo somewhere in the order or 350-400g at 70mph.

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