Kona_stig

I bought some tubes a while ago. The came with these. They look beyond weird to me.. what's the deal here? I also have nothing that will put air in them..

waldowales

Standard Presta. If you don't have a pump that fits, buy an adapter from the LBS for a buck or so, and ask them how to use it. If you are going to use them with rims drilled for Schraeder valves, you'll need a bushing for each one, also.

2manybikes

The one on the right is a presta tube. For bike tubes, it's as common as dirt. Most high end bikes have them.

The other is a schrader (like a car) almost all schrader pump heads can be taken apart have the rubber and plastic parts reversed and put back in to work on a presta valve.

You can google Presta-Schrader adapter and see the $2.00 adapter that will switch them over to the other kind. All bike shops should sell the adapters and the tubes of both kinds, you need to specify what type when you buy them. The bike shop should be able to show you how to reverse the pump head, but possibly not, depending on who you talk to. It's such a common mistake that a good bike shop will trade you for the other valve type if the tubes are new and you just bought them there.

HillRider

One difference between Presta and Schrader valves that isn't always obvious to first time users: the little brass knurled nut at the end of the valve must be unscrewed a number of turns to allow the valve to open and let in air and screwed shut once the tube is up to pressure and the pump chuck is removed.

veganboyjosh

it's as good a time as any to post this, and i apologize in advance for the thread hijack, but the OP's question seems to have been answered...

does anyone know what the difference is in performance between schraeder and presta valves? if my history is correct, schraeder valves came first. at some point, someone--mr presta?--said "you know, i've got a design that works better..."

but i've asked experienced wrenches, and pro riders, and no one seems to know why the option.

i do know that the presta valves don't have the spring to keep the valve closed that schraeder valves do, would this make a difference in performance?

aside from what sized hole your rims have, why would you choose on over the other? the only benefit i can see one having is schraeder valves you can fill at a gas station...without an adapter.

tdister

veganboyjosh

https://www.sheldonbrown.com/gloss_p.html

near the bottom of the page

pinerider

One reason to prefer a Presta valve is there is less likelihood of air leakage through the valve.

Kona_stig

Huh, alright. Thanks for the info!

Billy Bones

Another little detail that can be devilish to first-time Presta users is that the air seal "heals" a little bit between uses. Be sure to "burb" the valve before filling by tapping the stem inward after unscrewing the knurled nut and before filling the tube with air. My lame description my not be obvious so ask your LBS folk about this, too. This little issue can easily frustrate first timers.

HillRider

Good point. If you don't "burp" (nice term ) the valve first, the pump can get to astronomical pressure before the valve finally pops open. It can make you think you did forget to loosen the nut.

donheff

That little detail frustrated the heck out of me when I first got Prestas. I assumed the pump head didn't fit right or something. I think I finally figured it out by posting here somewhere.

fosmith

nice...april fools already

tippy

Since the presta's are found on lower volume tubes (23, 25, 28 etc), an accidental release of air would be a higher percentage of the total volume ... compared to a larger volume tube.

A presta valve closes the moment the pump pressure is less than the tube pressure so no tube volume is lost during disconnection.

A schrader holds the valve open until disconnection (and sometimes during disconnection) so it releases some tube volume ... alot if your not quick about it. This is not a big deal with higher volume (ballon) tires but it could make a difference with the skinny ones.

Maybe Mister "presta" got tired of over-inflating his skinny tires to compensate for the inevitable loss of volume and decided to make a valve stem that doesn't loose volume during disconnection.

K6-III

The main reason for the presta valve is the narrow rims that are used on road bikes.

Wordbiker

I always thought the main reason for presta valves is for cyclists to feel like they have an elite valve all their own, something not found on a dumptruck or a wheelbarrow. "Presta" just sounds so much more cosmopolitan than "Schraeder".

Joshua A.C. New

Sheldon's voice from the grave gives the surprising advice to not use the caps on Presta valves. I don't know about that. I've had a lot of valves bent. Obviously, while riding, not much is going to hit the valve, but leaning against a bench out in front of a café is a surprisingly dicey proposition for delicate parts. I leave mine on. Also, it can act as an impromptu adapter in a pinch when all you've got to go on is the air compressor at a gas station (cut the top off. You carry a knife, right?). It doesn't work *well*, but it will get enough air in there to limp to somewhere else.

StephenH

I've got a couple of tubes with Dunlop valves. A fairly useless thing to own.

I don't know the history of these things, either, but there's all kinds of mechanical doohickeys that vary just because different people in different places had different solutions for similar problems. Kind of like why we drive on the left or the right. Or why there's 18 different camera lens mounts or why there's 800 different kinds of small arms cartridges, etc.

alecw35

the problem with presta valves is that you cant get fancy valve caps for them.

Joshua A.C. New

Sure you can. You just need an adapter. Then you can put all the blinky lights, streamers, and dancing monkeys you want on there!

cyccommute 

What color do you want?

Edit: I just found this...if just changing color doesn't interest you.

cyccommute 

Assuming that this is not a joke. Here's how you use them

Unscrew the brass knurled nut on top so it looks like this



If it's already got air in it, burp it for just a fraction of a second



Use the little hole on your double headed pump



Push it on



Flip up the thumblock



and pump



To take the pump head off, reverse the order up to the burp part (you don't need to do that one again) and close the little knurled nut after you are done. Put the valve cover back on if you like.

enjoi

for the adapter, go to targets bike section, look for the cheapest pumps, take the adapter that is hidden it the locking lever, leave target.

Bikedued

Which is countered by the tendency of the stem base to rip out of the tube for no apparent reason.,,,,BD

operator

Take the knurled nut and throw it away.

masiman

Another feature I have only seen available for presta valves is the extended valve stems for aero section rims. I have seen truck inner tubes with longer valve stems but not shrader tubes for bikes. Valve extenders can also be found for presta. Something else I have not seen for shrader.

Nice links to the custom caps cyccommute. I may consider getting their bar plugs. Where did you find that company?