Bugatti Veyron wheels? Mental.
Discussion
King Herald said:
BigBen said:
Clearly they are a good belt and braces idea, but I stand by the fact they are not used on most cars. In fact I am fairly sure the faster of my cars has valve caps rather than dust caps, I am also sure the others don't, I suspect the major vehicle OEMs would not be selling cars which were unsafe at higher speeds for want of a 3p part.
Even the cheapest plastic OEM 'dust' cap will seal the valve, make it air tight. Baring in mind the actual valve core is the same as you find in a childs bicycle, I'd be worried about not having a valve cap of any sort on it.
Anyway happy to apologise, it has been a dust cap education thank you.j44esd said:
At the danger of wading into the most boring argument on PH, I feel you need some defending King Herald - you are of course, despite everyones incredulity, correct.
I'm offshore, doing 12 hour days with very little to occupy myself, thus things like the dust cap versus valve cap argument becomes of immense importance. 
King Herald said:
j44esd said:
At the danger of wading into the most boring argument on PH, I feel you need some defending King Herald - you are of course, despite everyones incredulity, correct.
I'm offshore, doing 12 hour days with very little to occupy myself, thus things like the dust cap versus valve cap argument becomes of immense importance. 
Dapster said:
King Herald said:
j44esd said:
At the danger of wading into the most boring argument on PH, I feel you need some defending King Herald - you are of course, despite everyones incredulity, correct.
I'm offshore, doing 12 hour days with very little to occupy myself, thus things like the dust cap versus valve cap argument becomes of immense importance. Every day's a school day. I'm actually amazed that a cheap plastic dust cap, with no kind of o-ring or other internal seal that I can see, is capable of containing the tyre pressure of a car tyre (~30psi), let alone that of a bike tyre (~60-100 psi). Some valve caps seem to have a rubber sealing ring inside the plastic cap but the cheap ones don't.
The presta valves on my bike of course have a screw-down collar on top that ensure that the valve is held closed mechanically, as well as by tyre pressure, not that I'm likely to be travelling fast enough for centrifugal force to open the valve....
The presta valves on my bike of course have a screw-down collar on top that ensure that the valve is held closed mechanically, as well as by tyre pressure, not that I'm likely to be travelling fast enough for centrifugal force to open the valve....
BGarside said:
Every day's a school day. I'm actually amazed that a cheap plastic dust cap, with no kind of o-ring or other internal seal that I can see, is capable of containing the tyre pressure of a car tyre (~30psi), let alone that of a bike tyre (~60-100 psi). Some valve caps seem to have a rubber sealing ring inside the plastic cap but the cheap ones don't.
The presta valves on my bike of course have a screw-down collar on top that ensure that the valve is held closed mechanically, as well as by tyre pressure, not that I'm likely to be travelling fast enough for centrifugal force to open the valve....
Maybe part of the purpose is that it slows any high speed deflation sufficiently to be considerably safer in the event of a valve failing?The presta valves on my bike of course have a screw-down collar on top that ensure that the valve is held closed mechanically, as well as by tyre pressure, not that I'm likely to be travelling fast enough for centrifugal force to open the valve....
zeDuffMan said:
Turbodiesel1976 said:
The ultimate first world problem 
I imagine if you can afford a million pound car you can afford a few sets of wheels throughout its life. Sounds unnecessary to me though, I doubt of the wheels on bullet trains get changed every 10,000 miles
I don't think it's an issue of whether millionaires can afford it or not, it's more they don't like being totally ripped off. I've read a few stories of owners that are sick of the high mandatory maintenance costs associated with the Veyron. And if you don't stick to the schedule, Bugatti won't touch the car at all. I imagine if you can afford a million pound car you can afford a few sets of wheels throughout its life. Sounds unnecessary to me though, I doubt of the wheels on bullet trains get changed every 10,000 milesRandy Winkman said:
Don't get in a debate with keen cyclists about valve caps. According to "The Rules" you should never keep them on:
http://www.velominati.com/the-rules/
It's as important as lining the valve stem up with the tyre label.
Slightly OT... but the "rules" refer to road cycling, where you use Presta valves which screw shut and as such would not need a sealing dust cap to aid the valve portion :-)http://www.velominati.com/the-rules/
It's as important as lining the valve stem up with the tyre label.
I'm almost surprised the Veyron uses something as mundane as normal valves anyway, why are the tyres not filled with hydrogen plasma only refillable at your local fusion power station and sealed with unobtainium caps with space shuttle tile heat shield material lining?
Incidentally I make SCUBA gear and just spent 30minutes removing schrader valves cores from a part that doesn't need them, I have about 10,000 cores on the shelf if any Veyron owners want some (they are only £7000 each to you ;-)
Dapster said:
You're alone with a high speed internet connection and you are reading about dust caps vs valve caps to keep yourself entertained?
High speed internet connection??? Bwaaahahahahaaaaa. The slowest dial up at home is twice as fast as our crappety crap connection here. And any web pages of 'real' interest get flashed up with a huge warning "BLOCKED URL CATEGORY". The company big brother web controller looking after our peace of mind I guess.......
007 VXR said:
yonex said:
World's (one time) fastest and most powerful production car in expensive to run shocker.
Who'd have thought?
The internet is a weird place Who'd have thought?
Why would you buy an Aventador, then rent it out on the streets????
N
supersingle said:
BTW even cheapo valve caps create an airtight seal. If you ride a motorbike at very high speed the tyres go flat if you've left the calve caps off. Ask the Straightliners boys about that.
Happened to me on the way to the Bol d'Or on my Exup. After a sustained 160mph+ ride, the handling went mushy. I had checked pressures before we left, but omitted to replace the cap. On re-checking, had 6 psi! Re-inflated, with a new cap and had no further problems. Worth noting that the valve exists to let air in (and of course, out) of the assembly (the tyre on the rim). The valve therefore has this as its primary function, a secondary function is of air retention - but the primary function of the cap is air retention, its secondary function being to keep dust and detritus away from the valve core.
Strangely everyone seems to have got hung up on the fact that the cap is a tiny threaded piece of plastic and therefore may fail, as if the valve is some mighty bolted down assembly - where of course the valve itself is also a small assembled part - the valve is the body that allows air in / out - the 'valve core' (which is the bit that you can press in to let air in / out) is also just a screwed in part - usually with only a few mm of thread.
The whole unit is required to function correctly, the valve body cannot leak or be damaged by centripetal / centrifugal force causing a leak elsewhere in the valve body, the core should be assembled correctly not leaking and allowing air to pass by into the valve body, whilst providing a secondary seal, as it is merely a rubber 'push' fitting - the picture below perhaps illustrates better the assembly 'broken down' in a few different valve lengths - and of course the cap should be fitted to prevent air escaping.
The big part is that (on the whole) a passenger car tyre valve is merely pulled through the wheel with force to fit - so a lot of this debate misses this quite important part out - you're all hung up on the cap / valve core when the whole assembly is merely pulled through by screwing a lever onto the top!
PS: All usual caveats apply, IANAL etc. etc. Ensure you seek professional advice before attempting any of the stunts on todays show....
Strangely everyone seems to have got hung up on the fact that the cap is a tiny threaded piece of plastic and therefore may fail, as if the valve is some mighty bolted down assembly - where of course the valve itself is also a small assembled part - the valve is the body that allows air in / out - the 'valve core' (which is the bit that you can press in to let air in / out) is also just a screwed in part - usually with only a few mm of thread.
The whole unit is required to function correctly, the valve body cannot leak or be damaged by centripetal / centrifugal force causing a leak elsewhere in the valve body, the core should be assembled correctly not leaking and allowing air to pass by into the valve body, whilst providing a secondary seal, as it is merely a rubber 'push' fitting - the picture below perhaps illustrates better the assembly 'broken down' in a few different valve lengths - and of course the cap should be fitted to prevent air escaping.
The big part is that (on the whole) a passenger car tyre valve is merely pulled through the wheel with force to fit - so a lot of this debate misses this quite important part out - you're all hung up on the cap / valve core when the whole assembly is merely pulled through by screwing a lever onto the top!
PS: All usual caveats apply, IANAL etc. etc. Ensure you seek professional advice before attempting any of the stunts on todays show....
Edited by j44esd on Wednesday 1st April 20:48
King Herald said:
Strange, the tide seems to have changed, from a bunch of valve cap brainiacs telling me I'm a farking idiot, to people queuing up to agree with me.
I hope the local village idiots can learn a thing or two from listening to other people, rather than automatically mocking them.
Hey! I agreed with you from the start! I was just boring everyone into submission with my second post! I hope the local village idiots can learn a thing or two from listening to other people, rather than automatically mocking them.
The majority of valve caps won't seal anything for any length of time. Hard plastic and brass pressed together by the maximum force that can be generated by means of a crummy and very fine plastic thread don't seal sweet f-a.
This isn't about cars or tyres, any person who actually gets their hands dirty doing whatever will call that theory what it really is. That a plastic valve cap as fitted to the majority of valves is not designed to seal is obvious for any of the above category of person that someone who thinks otherwise evidently is quite the opposite.
If you presented a common dust cap to an engineer as a design for a "seal" for anything you'd get all the condescending looks you'd deserve.
I and no doubt millions of people worldwide have run tyres for years without valve caps, speaking only for myself, I have never had tyres deflate for want of one.
I have no doubt that it is possible to design a valve cap that will seal - and some may well be capable of that - that's not the point, the point is that ordinarily the valve does the sealing and if it does not, then that valve needs replacing, trying to seal it with a dust cap is a bodge.
As for centrifugal force opening a valve, I don't know, certainly theoretically possible, the force keeping a valve closed at a given air pressure can be relatively easily determined knowing the diameter of the valve insert seal, and the centrifugal force the valve is subjected to at a certain radius and angular velocity, too, knowing the mass of this same valve insert, so if anyone is up to it they can do the measuring and maths and find out. I suspect that valve makers have this sussed out however.
This isn't about cars or tyres, any person who actually gets their hands dirty doing whatever will call that theory what it really is. That a plastic valve cap as fitted to the majority of valves is not designed to seal is obvious for any of the above category of person that someone who thinks otherwise evidently is quite the opposite.
If you presented a common dust cap to an engineer as a design for a "seal" for anything you'd get all the condescending looks you'd deserve.
I and no doubt millions of people worldwide have run tyres for years without valve caps, speaking only for myself, I have never had tyres deflate for want of one.
I have no doubt that it is possible to design a valve cap that will seal - and some may well be capable of that - that's not the point, the point is that ordinarily the valve does the sealing and if it does not, then that valve needs replacing, trying to seal it with a dust cap is a bodge.
As for centrifugal force opening a valve, I don't know, certainly theoretically possible, the force keeping a valve closed at a given air pressure can be relatively easily determined knowing the diameter of the valve insert seal, and the centrifugal force the valve is subjected to at a certain radius and angular velocity, too, knowing the mass of this same valve insert, so if anyone is up to it they can do the measuring and maths and find out. I suspect that valve makers have this sussed out however.
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