Are Presta valve caps uncool or what?
#76
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Oi ... you people must have studied physics in some reputable, accredited school.
Here's the real deal: as the valves-With Caps--pass vertical and begin falling, the exert a gravitational force on the rim, accelerating it. Now some of you who think you "know" physics will try to claim that the same force is lost as the valve rises up the back half of the revolution- --BUT ...
the improved aerodynamics (engineers spent a Lot of time shaping those caps) means that the force needed to lift the capped valves is reduced compared to an uncapped valve ..... thus you actually gain energy.
If your valve caps were big enough you could (theoretically) power your home by riding your bike.
Unfortunately the weight and drag associated with storage and transmission devices outweigh the energy gain, or we'd all be punching in to do our eight-hour riding shifts each day to keep the utility companies in business.
Here's the real deal: as the valves-With Caps--pass vertical and begin falling, the exert a gravitational force on the rim, accelerating it. Now some of you who think you "know" physics will try to claim that the same force is lost as the valve rises up the back half of the revolution- --BUT ...
the improved aerodynamics (engineers spent a Lot of time shaping those caps) means that the force needed to lift the capped valves is reduced compared to an uncapped valve ..... thus you actually gain energy.
If your valve caps were big enough you could (theoretically) power your home by riding your bike.
Unfortunately the weight and drag associated with storage and transmission devices outweigh the energy gain, or we'd all be punching in to do our eight-hour riding shifts each day to keep the utility companies in business.
#77
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#78
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You got that right......... I can't wait for the weather to clear-up, so I can start riding again. And we can start worrying about aerodynamics of Campy cranks and climbing. I took the yellow caps of my Ciocc, after this discussion, will replace with red ones, as we all know, RED is faster .KB
#79
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I prefer the oversized valve caps that double as shot glasses. Handy on the pub crawling bke.
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Vintage, modern, e-road. It is a big cycling universe.
Vintage, modern, e-road. It is a big cycling universe.
#80
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Little known fact: As Tom Simpson was climbing Mont Ventoux, he looked down and realized his mechanic had left the valve caps on. He had a heart attack out of sheer embarrassment.
Later they said his death was due to mixing booze and amphetamines -- the family made this up to protect his reputation.
Later they said his death was due to mixing booze and amphetamines -- the family made this up to protect his reputation.
#81
Me duelen las nalgas
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I think they are cool. I've been saving them for years. Gotta small can of them. I have a little ritual for all new tubes. Unscrew the cap and nut, but in the can and install the tube. Problem is, I haven't found a good use yet for those caps and nuts. But they gotta be good for something. They are just that cool!
But re-screwing it onto the tire so I have to unscrew it after I flat? Then keep track of it so I can screw it back on? Seems like wasted effort to me. And I have had way too few instances where a cap even might have made a difference for the better.
Ben
But re-screwing it onto the tire so I have to unscrew it after I flat? Then keep track of it so I can screw it back on? Seems like wasted effort to me. And I have had way too few instances where a cap even might have made a difference for the better.
Ben
Sneaky bastards are trying to pawn them off on unsuspecting customers.
#82
aka Phil Jungels
All this talk prompted me to buy a bag of anodized aluminum presta valve caps, off of Amazon, to replace the missing or cheap plastic ones on my bikes. Really uncool, to say the least, but they should last!
#83
Cycleway town
Plastic ones are bad for the environment. Very few get recycled, they end up in the water systems and are picked up by birds and small animals. Especially the bright ones.
#85
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Once while crashing my bike I ended up semi tangled up with it. My hand was somehow stuck in the wheel, and something was jabbing my wrist horribly. Turned out it was my valve cap. Paramedics said had it not been for the cap, the dangerous valve tip likely would have ensured that I bled to death! Said they've seen it many times before. My valve cap saved my life!
Ever since having had this close call with death, I'd sooner ride without a helmet than my valve caps. Safety First!
Ever since having had this close call with death, I'd sooner ride without a helmet than my valve caps. Safety First!
#86
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Blackburn must have a huge collection of Presta valve caps and nuts too. My Blackburn Core Slim pump came with very familiar looking plastic doodads and nuts holding the pump and bottle cage mount to the cardboard display packaging. When I removed the caps and nuts I realized they were from Presta valves.
Sneaky bastards are trying to pawn them off on unsuspecting customers.
Sneaky bastards are trying to pawn them off on unsuspecting customers.
Ben
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Ben
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I usually leave the little plastic caps on, but don't worry if they get lost.
I do like to throw a Presta/Schrader adapter on in place of one of the caps, but don't put a cap over the adapter.
The nuts are handy to hold the valve in place when attaching the pump, especially if one has short valve stems.
I do like to throw a Presta/Schrader adapter on in place of one of the caps, but don't put a cap over the adapter.
The nuts are handy to hold the valve in place when attaching the pump, especially if one has short valve stems.
#92
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Awright, guys, I just removed the caps and nuts from my Presta valves.
This is making me nervous. The valve stems can move very slightly. Won't that rob at least as much energy as the video camera mount zip tied to my helmet, and that extra tire lever in my seat bag? I know some folks only need one, but what if a squirrel steals my one tire lever while I'm fumbling around on the side of the road?
Strava better show me a 10W boost or those things are going right back on.
This is making me nervous. The valve stems can move very slightly. Won't that rob at least as much energy as the video camera mount zip tied to my helmet, and that extra tire lever in my seat bag? I know some folks only need one, but what if a squirrel steals my one tire lever while I'm fumbling around on the side of the road?
Strava better show me a 10W boost or those things are going right back on.
#93
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Awright, guys, I just removed the caps and nuts from my Presta valves.
This is making me nervous. The valve stems can move very slightly. Won't that rob at least as much energy as the video camera mount zip tied to my helmet, and that extra tire lever in my seat bag? I know some folks only need one, but what if a squirrel steals my one tire lever while I'm fumbling around on the side of the road?
Strava better show me a 10W boost or those things are going right back on.
This is making me nervous. The valve stems can move very slightly. Won't that rob at least as much energy as the video camera mount zip tied to my helmet, and that extra tire lever in my seat bag? I know some folks only need one, but what if a squirrel steals my one tire lever while I'm fumbling around on the side of the road?
Strava better show me a 10W boost or those things are going right back on.
Even if you don't net half a watt, you have to look at the bright side here, CC... Without those pesky caps you'll be able to swap a tube out with the fast boys.
#95
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Presta caps are the bain of the weight weenie racer boys. If they entered a 500 mile race, removing the caps would mean they would cross the finish line .763956241 inches ahead of where they would have if they had left the caps on.
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Just for giggles, or because I was bored, I emailed a manufacturer of presta valve's and asked them their policy on caps and lock nuts. "Yes. We recommend to use cap. To avoid dust. And recommend to use locknut too. " So all you sloppy unkempt pin bending impaling death machine riding folks are going against manufacturer's recommendations. Good luck with your lawsuit
#97
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Just for giggles, or because I was bored, I emailed a manufacturer of presta valve's and asked them their policy on caps and lock nuts. "Yes. We recommend to use cap. To avoid dust. And recommend to use locknut too. " So all you sloppy unkempt pin bending impaling death machine riding folks are going against manufacturer's recommendations. Good luck with your lawsuit
Well done! That oughta net us another page or two.
On the other hand, anyone who rides "Electroforged" surely can't be taken as a serious cyclist.
Yes, I have several of them!
#98
Farmer tan
And you guys wonder why squirrels try to run through the spinning wheels...
They're after the attractively colored, moving caps on your bike.
They're after the attractively colored, moving caps on your bike.
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I.... I had no idea this was such a controversial topic. But, I'll share what I do, anyway.
I use them on the commuter bike to keep the grime/salt/ick out of the valve. Sometimes the wheels will have a nice layer of salt and I like the valve to be clean.
On the racing bike, I just never put them on in the first place. No particular reason...just one less thing to worry about, I guess.
I use them on the commuter bike to keep the grime/salt/ick out of the valve. Sometimes the wheels will have a nice layer of salt and I like the valve to be clean.
On the racing bike, I just never put them on in the first place. No particular reason...just one less thing to worry about, I guess.
#100
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There is a busy cycle path behind my house. You always know the "too cool" or "velominati" riders because as they go over the bumps right behind the house you can hear their valve stem slamming back and forth against the pass thru in the rim.
Yeah, that little retention nut isn't cool huh?
I use mine and never hear that annoying noise.
They give you something to use for it with your tube/tub, but then those same guys take it to the other extreme and use either a piece of electrical tape OR even going to lengths of using heat shrink over the stem at the hole thru the rim.
Good Lord, that's just tooooo much. I'll use the damn nut and dust cap.
Yeah, that little retention nut isn't cool huh?
I use mine and never hear that annoying noise.
They give you something to use for it with your tube/tub, but then those same guys take it to the other extreme and use either a piece of electrical tape OR even going to lengths of using heat shrink over the stem at the hole thru the rim.
Good Lord, that's just tooooo much. I'll use the damn nut and dust cap.