mm718

OK, my newbie mechanical skills are coming along... I've changed 3 tires, done the back wheel thing twice but now the presta valve is frustrating me to no end. Here's what's been happening. I loosen the presta valve, give it a quick tap, attach my new Nashbar pump with it's "smart" head, and begin pumping. Sometimes the first pump goes well and it accepts the air but often it won't take the second pump like the valve is closed but the valve is wide open. When it does accept the air I'm pumping in I can often hear the air slowly escaping. Then there's times when I've overfilled and want to let just a little bit of air out using the button on my pump. One tap will hardly do anything but a slightly longer tap will deflate tens of lbs. What I am doing wrong? Forty years of zero problems with Schrader but I can't do the simplest thing with these Presta valves...

Booger1

Aren't presta valves great?

Another wonderful French invention:

ThermionicScott 

I'm not much of a fan either. After breaking a couple with clunky pump heads, I generally keep a Schrader pump and adapter handy.

cyccommute 

Wiggle the head a little on the valve if air isn't going into the tube. Often this is enough to open the valve and let air in. You can also just keep pumping. Eventually the pressure will open the valve.

The air leaking out of the hose isn't anything to be worried about. Because of the way that presta valves work, no air leaks out of the tube like it will on a schrader valve. All you are hearing is bleeding off of pressure in the pump hose.

Use your finger to tap a presta valve to release air. You don't need a tool, just push down on it. Using something to depress the valve makes judging how much air you are releasing harder.

mm718

Just tried that and it worked beautifully. Is there any downside to this. Because if not I am going to buy another presta/schrader adapter and keep them on both valves. Thx.

mm718

Thanks for the excellent info, cc. That makes sense about the bleeding off of pressure and good to know that the valve will open itself with enough pressure. I do like the tap of the presta valve.

Bill

I have struggled with this for years. I have figured that this is just the way they are. When it first happened I thought I would never get air in the tubes.

ThermionicScott 

None that I can think of, apart from the inconvenience. If you decide to store the adapters on the valve stems, it's probably a good idea to screw down the Presta nuts after refilling, then put the adapters back on.

I should just practice my Presta-handling skills, but I hate the thought of changing yet another tube if I can prevent it.

commo_soulja

It's a preta valve, what's so difficult?

dpeters11

It does take soe getting used to when you hav mostly dealt with Schraeder.

rekmeyata

Do be careful pumping a modern presta tube though, they no longer reinforce the valve going into the tube so they can save 5 cents; this weakened area now allows for mini pumps that attach directly to the valve to rip when the psi gets high and the level of force on the pump gets high and the rider can't hold the valve and pump steady enough. That's why you need to get a mini pump with a hose, and Topeak Road Morph is the best one for the money, or if money is no issue and your a weigh wienie then the Lezyne Road Drive is the next best one.

rogerstg

+1, I can remember thinking that something was wrong with my pump. In reality, I was treating it like it was a schraeder valve and pushing the pump head on too much (was used to pushing hard enough for the center pin to push down on the valve seal)

Once I started simply putting the pump head over the valve stem it became easy.

Doohickie

As was said upthread.... 40+ years of Schrader valves, never one problem. Recently starting using Prestas and have had several valve failures- the valve pulls out of the tube, the stem breaks, etc. The tradeoff I see is this: Robust design with a spring that never breaks, versus a more delicate design that often breaks with normal use. That's what's so difficult.

pdlamb

The pump is the problem. Well over half the dual head pumps sold today are simply horrid.

But if you like Schraeder, you can pump the tube from 50 psi up to 100 psi, start unscrewing the pump head, and listen carefully as 50 psi leak out before you get it removed from the valve. (Won't happen with a Presta!)

rekmeyata

Actually for another experiment I was doing, I pumped up a MTB tire with a schrader valve to 220psi! Of course I stuck the wheel in a trash can then shot air into from my compressor using a remote air trigger and me behind my car just in case it exploded, but nothing happened. I keep the pressure in for 2 weeks, at the end of 2 weeks I think the pressure dropped about 50 or 60 psi, the schrader valve held just fine. This was done due to another forum member saying that a glueless patch couldn't take high pressures, the test proved him wrong which I knew it would but wanted to see for myself to make sure. I was more surprised that the tire didn't blow off the rim then anything else.

bigbadwullf

Is there a lever on the pump head to clamp it on the valve? If so, clamp away before pumping and unclamp before removing.

mm718

Yeah, TS-- I've been doing this but wasn't sure if it was necessary so thanks for the tip. Picked up my second adapter today and will see how it goes.

mm718

BBW-I think I was occasionally forgetting to do this. In my mind the pump lever should be down when clamped but with the nashbar pump it's the opposite so I may have been under the impression that it was clamped when it wasn't

mm718

Thanks everyone for your help. Now on to mirror shopping...