# Presta Valve Caps - to use or not to use?



## psunuc (Mar 15, 2005)

I was just wondering what everyone's preference was on using valve caps for presta valves. I was actually considering not using them because it is so easy to just wipe dirt away from the valve before putting air into the tire. I figured I would see what the consensus was, thanks.


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## shiggy (Dec 19, 1998)

Never seen the need.


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## immtbman (Nov 22, 2005)

I use `em. Won't find them on my road bike, but on the mtb worry a bit about grit down inside the stem around those tiny threads and the rubber seal on the end that closes off the air passage. Cable boots on brakes and derailluers exist for similar reasons - to protect potentially sensitive areas from abrasive elements.


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## shiggy (Dec 19, 1998)

immtbman said:


> I use `em. Won't find them on my road bike, but on the mtb worry a bit about grit down inside the stem around those tiny threads and the rubber seal on the end that closes off the air passage. Cable boots on brakes and derailluers exist for similar reasons - to protect potentially sensitive areas from abrasive elements.


Not an issue


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## EliM (May 6, 2006)

Not normally.


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## meloh1 (Jan 13, 2004)

Definitely use them. They are necessary. Without them your wheel will be out of balance because the stem AND cap balance the pinned or welded rim joint on the opposite side of the rim. You risk injury and even death if you fail to properly use the stem cap. You've been warned.


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## GRAVELBIKE (Oct 7, 2006)

meloh1 said:


> Definitely use them. They are necessary. Without them your wheel will be out of balance because the stem AND cap balance the pinned or welded rim joint on the opposite side of the rim. You risk injury and even death if you fail to properly use the stem cap. You've been warned.


Is it a slow and painful death, or quick and painless?


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## NorKal (Jan 13, 2005)

shiggy said:


> Never seen the need.


How about on a new tube you carry in your pack so the stem doesn't pucture the tube?

Other than that, yeah probably no need.


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## shiggy (Dec 19, 1998)

Khemical said:


> How about on a new tube you carry in your pack so the stem doesn't pucture the tube?
> 
> Other than that, yeah probably no need.


Sometimes. Usually I put the tube in an old sock and wrap the valve into the sock the protect the tube. I also fold the tube with the valve on the outside.


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## NorKal (Jan 13, 2005)

shiggy said:


> Sometimes. Usually I put the tube in an old sock and wrap the valve into the sock the protect the tube. I also fold the tube with the valve on the outside.


I usually put my tubes in one or two ziplock baggies with a coupla shakes of baby power to keep them from sticking and give them that new-baby smell.


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## RomSpaceKnight (Aug 16, 2006)

Are you a weight weenie and feel it slows down your attacks? It keeps stuff from plugging, damaging or otherwise interfering with the valve. Use 'em.


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## forkboy (Apr 20, 2004)

psunuc said:


> I was just wondering what everyone's preference was on using valve caps for presta valves..


Just because the fit in your nose doesn't mean you should put them there.


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## psunuc (Mar 15, 2005)

The cap doesn't balance anything. If you are talking about angular momentum, the weight of that cap is negligible.


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## meloh1 (Jan 13, 2004)

Definitely slow and painless, like putting a frog in a pot of cold water and slowly raising the temperature until it's boiled to death.


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## shiggy (Dec 19, 1998)

RomSpaceKnight said:


> Are you a weight weenie and feel it slows down your attacks? It keeps stuff from plugging, damaging or otherwise interfering with the valve. Use 'em.


Let's see...in 25+ years how many presta valves have I had fouled because I did not use a valve cap?

Hmmm...that would be exactly ZERO.


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## beeristasty (Jan 22, 2004)

RomSpaceKnight said:


> Are you a weight weenie and feel it slows down your attacks? It keeps stuff from plugging, damaging or otherwise interfering with the valve. Use 'em.


Are you thinking of Schrader valves? I'd use caps with those when riding dirt. Presta can survive without caps, as the twist down part of the valve acts as a cap. Of course the caps may offer a little protection, but you have to be riding some gnarly stick-laden trails to get your money's worth out of them. The only time I use the caps is on my spares so the tips don't wear through the tubes. That's the only thing that's keeping it above spoke protectors on my list of useless "parts".


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## SuperNewb (Mar 6, 2004)

What about the nut for it as well? :eekster:


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## Random Drivel (Oct 20, 2006)

I take them off because they otherwise slow down my attacks up the steeps. I also believe in removing decals, evry third knob on my tires, and seat coverings to save weight as well . . . . but removing them does cause a wheel imbalance, so I just shave off half a gram from the rim, near the seam . . . .


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## ironbike1 (Jun 9, 2006)

I am truly having a hard time trying to figure out what difference it makes if they are on or off. I see tons of cars without them on & they operate just fine, same goes for MT. Bikes. On the same hand I see tons with them on & they operate just fine. 

For those of you who do not use them, what is the Benefit to leaving them off?


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## NorKal (Jan 13, 2005)

Random Drivel said:


> I take them off because they otherwise slow down my attacks up the steeps. I also believe in removing decals, evry third knob on my tires, and seat coverings to save weight as well . . . . but removing them does cause a wheel imbalance, so I just shave off half a gram from the rim, near the seam . . . .


Why not just ride nekkid. No clothes aughta save a few ounces eh?


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## shiggy (Dec 19, 1998)

ironbike1 said:


> I am truly having a hard time trying to figure out what difference it makes if they are on or off. I see tons of cars without them on & they operate just fine, same goes for MT. Bikes. On the same hand I see tons with them on & they operate just fine.
> 
> For those of you who do not use them, what is the Benefit to leaving them off?


Never seen a car with presta valves.

Benefit of not using caps? They do not need to be removed and replaced when you air up.


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## shiggy (Dec 19, 1998)

SuperNewb said:


> What about the nut for it as well? :eekster:


I only use the nut to keep the valve from pushing into the rim when airing up (if needed). Never tighten the nut on an inflated tire. It can contribute to tube/valve stem damage (holds it too rigidly) if the tire slips on the rim or something hits the valve.


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## Andino (Oct 27, 2005)

ehh...i dont use them on my roadie. on my mtb, i have these cool aluminum ones from my old mtb, i just use them cuz i have some cool ones to put on there...there is no need for them


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## bwolmarans (May 25, 2005)

when I first started mountainbiking I tore a few valve stems because nobody told me not to tighten the stupid little nut.



shiggy said:


> I only use the nut to keep the valve from pushing into the rim when airing up (if needed). Never tighten the nut on an inflated tire. It can contribute to tube/valve stem damage (holds it too rigidly) if the tire slips on the rim or something hits the valve.


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## Ross W. (Jul 3, 2006)

bwolmarans said:


> when I first started mountainbiking I tore a few valve stems because nobody told me not to tighten the stupid little nut.


hmmm, I never thought about this. Makes sense, although I have to say, I crank mine down and I've never had a problem in five years.


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## kapusta (Jan 17, 2004)

psunuc said:


> I was just wondering what everyone's preference was on using valve caps for presta valves. I was actually considering not using them because it is so easy to just wipe dirt away from the valve before putting air into the tire. I figured I would see what the consensus was, thanks.


I use them so I have something to lose every time I change a flat on the trail. Up until I started using valve caps, I was always losing/leaving something important on the trail, usually a tire lever. Now I just lose the valve cap.

It's perfect. I don't lose anything I really need, and I'm giving a little something back to the trail I love. Trails in no less than 6 states have recieved these little plastic tolkens of my appreciation, gifts than with endure for decades.


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## shiggy (Dec 19, 1998)

Ross W. said:


> hmmm, I never thought about this. Makes sense, although I have to say, I crank mine down and I've never had a problem in five years.


Ever notice how hard it is to remove the nut when the tire is flat?


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## kapusta (Jan 17, 2004)

shiggy said:


> Ever notice how hard it is to remove the nut when the tire is flat?


No.

I've always cranked it down. Didn't know any better. Never had a problem in the 8 years I've been using presta. But what you say makes sense. Guess I'm not really doing anything useful by tightening it.


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## SHIVER ME TIMBERS (Jan 12, 2004)

I like the clean look of having it on........I have had presta valves get sticky with dirt.....I took it out and cleaned it and put it back together......in high dust areas i would recommend having the cap on


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## forkboy (Apr 20, 2004)

shiggy said:


> I only use the nut to keep the valve from pushing into the rim when airing up (if needed).


What about Mavic's new copout with their rims - instead of drilling for Presta, they drill for Schraeder and put a little plastic insert to hold the Presta stem in place. Then the little plastic insert falls out if you don't have the nut on...

Who's going to run Schraeders on a set of 717's?


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## psunuc (Mar 15, 2005)

For the second time....*the cap doesn't balance the wheel at all*. The weight isn't enough to cause an imbalance. The cap may weigh one gram while the wheel with tube and tire weighs about 2000g. You need to use the equation for angular momentum for this.

Angular Momentum (H) = (position vector (rho)) X (velocity (v))*(mass (m))

Clearly 1 gram is negligible. The difference does not matter.

Because the cap has mass it will imbalance the wheel actually.


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## Herbert (Jun 23, 2004)

I don't use them on my bikes at all, but do keep them on my spares but more so because I don't think about removing them.

Herbert
Litespeed

www.litespeed.com


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## kapusta (Jan 17, 2004)

psunuc said:


> For the second time....*the cap doesn't balance the wheel at all*. The weight isn't enough to cause an imbalance. The cap may weigh one gram while the wheel with tube and tire weighs about 2000g. You need to use the equation for angular momentum for this.
> 
> Angular Momentum (H) = (position vector (rho)) X (velocity (v))*(mass (m))
> 
> ...


I think somebody has missed a joke.


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## Crash_Burn (Oct 8, 2004)

*Red caps make you faster!*



psunuc said:


> I was just wondering what everyone's preference was on using valve caps for presta valves.


I use the red caps to locate the valve quicker, spare and in the rim. I must be visually challenged.

I throw out the black ones and keep the red ones.


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## tomk96 (Nov 10, 2004)

bwolmarans said:


> when I first started mountainbiking I tore a few valve stems because nobody told me not to tighten the stupid little nut.


I never used to use them and had a bunch of flats where the valve stem meets the rest of the tube. Now I tighten them up and don't have problems. It may have been the tires I was running too, but I tighten it up.

I try and keep the caps on. Bad weather corrodes the valve stem a bit. Can make it hard to untighten in the cold. But don't worry about not having it either.


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## SHIVER ME TIMBERS (Jan 12, 2004)

kapusta said:


> I think somebody has missed a joke.


by far


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## iviguy (Oct 26, 2004)

Don't use them. They add to much weight to the wheels.....


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## hugh088 (Feb 1, 2004)

forkboy said:


> Just because the fit in your nose doesn't mean you should put them there.


Very infomative post.
The next time I ride, I leave them out of my nose.
With this info I am no longer afraid to buy a tricycle. If I rode with my IPOD where would I put the third one.


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## forkboy (Apr 20, 2004)

hugh088 said:


> If I rode with my IPOD where would I put the third one.


Do you really need me to answer that?


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## meloh1 (Jan 13, 2004)

Besides avoiding death the other advantage to using them relates to my workshop. If I don't keep them on the tube the darn things just litter my whole shop. I trip on them on the floor. They get in the way on the workbench. They cause my garbage can to overflow. They are the bane of my existance if they are not properly afixed to the tube. You've been warned, a second time.


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## shiggy (Dec 19, 1998)

forkboy said:


> What about Mavic's new copout with their rims - instead of drilling for Presta, they drill for Schraeder and put a little plastic insert to hold the Presta stem in place. Then the little plastic insert falls out if you don't have the nut on...
> 
> Who's going to run Schraeders on a set of 717's?


Sounds like user error. Schraeder to presta rim adaptors are fitted from the inside of the rim where it can not fall out regardless if you use the nut or not.


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## meloh1 (Jan 13, 2004)

That's the main reason I buy Salsa tubes!


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## forkboy (Apr 20, 2004)

shiggy said:


> Sounds like user error. Schraeder to presta rim adaptors are fitted from the inside of the rim where it can not fall out regardless if you use the nut or not.


No kidding. That thought never even crossed my mind.

2 sets of wheels I bought, and both were like that.... Another set on a biddies built-bike showed up like that as well.

Makes sense - I've lost a few tubes to wear caused by the valve-stem hole.

Thanks for the tip! Time to flip some not-so-stupid little plastic washers..


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## ironbike1 (Jun 9, 2006)

shiggy said:



> Never seen a car with presta valves.
> 
> .


My bad I didn't read the title carefully enough in between trick or treaters last night. I thought it was about schrader valve caps.


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## cmdrpiffle (May 8, 2004)

*Some use*

The only thing I've ever found useful is to leave them on a tube you've got folded up in your bag or CamelBack. Keeps the end of the valve from poking through the rubber on the spare.

Otherwise they're good for flicking at squirrels.

Cheers


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