Presta Valves-WHY?

Quoted message said:

Schrader is faster, and no adapter to mess around with.

all you do is use some locktite to keep the presta valve open and then screw on
a adapter and leave it in place. no big deal.

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Steve Knight said:

Quoted message said:

Schrader is faster, and no adapter to mess around with.

all you do is use some locktite to keep the presta valve open and
then screw on a adapter and leave it in place. no big deal.

Why would you need Loctite? Just screw on the adapter and it's functionally
a Shraeder.

Bill "memories of first mtb (only had a cheap auto foot-pump)" S.

"Dave Stallard" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

The one thing you must watch out for is the greater fragility of Presta
valves. In particular, if you're pumping one up with a handpump, put
your other hand in back of the valve to brace it. (This goes double
for long-stem Presta valves, which I'm unfortunately stuck with since I
went with CXP-33 rims)

I wrap by hand around the tire and hold the tire and pump.

Mark Jones said:

"Dave Stallard" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

The one thing you must watch out for is the greater fragility of Presta
valves. In particular, if you're pumping one up with a handpump, put
your other hand in back of the valve to brace it. (This goes double
for long-stem Presta valves, which I'm unfortunately stuck with since I
went with CXP-33 rims)

I wrap by hand around the tire and hold the tire and pump.

Another tip: When you pump them up, don't unscrew the nut all the way to
the end. That seems to get in the way of the sealing action the pump
needs to work. Instead, just unscrew it about halfway out. Works for
me, anyway.

Dave

On 10 Aug 2004 11:42:41 GMT, [email hidden] (Fx199) wrote in message
<[email hidden]>:

Quoted message said:

Schrader is faster, and no adapter to mess around with.

No detectable difference in inflation speed, no adapter required since
all my pumps handle both types. Next?

Guy
--
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88% of helmet statistics are made up, 65% of them at Washington University

Bob Newman said:

Isn't Presta supposed to handle higher pressures better?

Are you asking or is this a subtle way of telling? How do you imagine
one type of valve could handle bicycle tire pressures better than
another? Are you aware of the uses of Schrader valves in industry
where they are often used for pressures above 200psi? Highway trucks
generally run pressures higher than those in bicycle tires as well.

Presta valves are narrower and were also important in the days of yore
when racers changed and pumped tubular tires when they had flats in
professional races. Presta valve stems are narrower and have no
return spring to impede air passage from a hand pump. The stem hole
in a rim is the weakest place and limits spoke tension for a given rim
by the remaining metal around the hole when spoke tension hoop stress
acts on it, especially when that part of the rim is in the ground
contact point.

Jobst Brandt
[email hidden]

Pete who? said:

Quoted message said:

Isn't Presta supposed to handle higher pressures better?

Quoted message said:

Well... if you consider that aircraft tires use Schraeder valves,
and they are regularly pressurized to 250 or so. And then you put a
couple hundred thousand pounds of aircraft down on it.

Tire pressure does not change when the tire is loaded. Consider the
spare in a car inflated to design specifications and that the tire
does not need to be under load. Do you ask all passengers to get out
of your car before you check inflation pressure. If you do, that is
unnecessary. Try it on your bicycle if you care.

"Schrader"

Jobst Brandt
[email hidden]

"Hunrobe" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Given all this the question becomes, what advantages do you think

Schraders

Quoted message said:

offer that make it worth the hassle of drilling out the rims and the

attendant

Quoted message said:

risk of significantly weakening the rims?

Additionally, when I'm on the road and I get a flat I use a CO2 inflator to
pump up my tire. Do they even make these for Schrader?

Dave

Raoul Duke said:

"Hunrobe" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Given all this the question becomes, what advantages do you think
Schraders offer that make it worth the hassle of drilling out the
rims and the attendant risk of significantly weakening the rims?

Additionally, when I'm on the road and I get a flat I use a CO2
inflator to pump up my tire. Do they even make these for Schrader?

Yes.

Bill "wordsmith" S.

Yes. I just bought one that does both. Ultraflate Plus from
Innovations.
David

Raoul Duke said:

"Hunrobe" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Given all this the question becomes, what advantages do you think

Schraders

Quoted message said:

offer that make it worth the hassle of drilling out the rims and the

attendant

Quoted message said:

risk of significantly weakening the rims?

Additionally, when I'm on the road and I get a flat I use a CO2 inflator to
pump up my tire. Do they even make these for Schrader?

Dave

<[email hidden]> wrote

Quoted message said:

Tire pressure does not change when the tire is loaded. Consider the
spare in a car inflated to design specifications and that the tire
does not need to be under load. Do you ask all passengers to get out
of your car before you check inflation pressure. If you do, that is
unnecessary. Try it on your bicycle if you care.

Right. That was one of the trick questions we used to ask new airmen.
Q. "What happens to the tire pressure when you put the aircraft back on the
ground?"
A. "Nothing"

Quoted message said:

"Schrader"

I've seen it both ways. But I defer to the master...🙂

Pete

Hunrobe said:

>[email hidden]

Given all this the question becomes, what advantages do you think Schraders
offer that make it worth the hassle of drilling out the rims and the attendant
risk of significantly weakening the rims?

Regards,
Bob Hunt

Schraders are way more durable than prestas. Whether rim weakening is significant or not would depend on the rim. Taking a reamer to the rim isn't much of a hassle.

"Fx199" <[email hidden]> wrote in message news:[email hidden]...

Quoted message said:

I have a new bike with presta valves...

all my previous bikes have been converted to Schrader...

any reason not to?

Yep, you'll be called a FRED if you show up riding
kid's stuff.

(Hunrobe) said:

Both Presta and Schrader valves work so what do Schraders offer that Prestas do
not?

Infrastructure.

Chalo Colina

"Mark Jones" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Quoted message said:

A narrow light weight rim might not be able to accomodate the larger
hole required for a Shrader valve.

Very true. I do not think that the rims on my Trek 1200 could
handle a Schrader valve. The hole would be getting real close
to the edge of the rim.

When I acquired my current bicycle it had Schrader sized holes in the rim
but had presta valves with an adaptor to enable them to fill the full valve
hole inserted in the rim. Shrug. I would have had schrader's inserted,
but my LBS was out of stock of tubes in that size.

kind of the worst of both worlds.

Quoted message said:

all you do is use some locktite to keep the presta valve open and then screw
on
a adapter and leave it in place. no big deal.

So you ride around with an adapter on the thing all the time? LOL

Quoted message said:

No detectable difference in inflation speed, no adapter required since
all my pumps handle both types. Next?

Guy

My pump I guess is schrader specific unless I adapt it.

Next?

There is a pressure change in the tire when under load. In most cases
(especially bike tires) the change in imperceptible because the volume
change of the tire from being under load is very small compared to volume
change in air when pumped into the tire.

Try squashing a baloon with a pressure guage on it.

"Pete" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

<[email hidden]> wrote

Quoted message said:

Tire pressure does not change when the tire is loaded. Consider the
spare in a car inflated to design specifications and that the tire
does not need to be under load. Do you ask all passengers to get out
of your car before you check inflation pressure. If you do, that is
unnecessary. Try it on your bicycle if you care.

Right. That was one of the trick questions we used to ask new airmen.
Q. "What happens to the tire pressure when you put the aircraft back on

the

Quoted message said:

ground?"
A. "Nothing"

Quoted message said:

"Schrader"

I've seen it both ways. But I defer to the master...🙂

Pete

"Doremi" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

There is a pressure change in the tire when under load. In most cases
(especially bike tires) the change in imperceptible because the volume
change of the tire from being under load is very small compared to volume
change in air when pumped into the tire.

Try squashing a baloon with a pressure guage on it.

Well, yeah. If you change the volume significantly, the internal pressure
will change.
But in any normal construction tire (bike/car/airplane), the volume doesn't
really change when you go from unloaded to loaded.

So no measurable change in pressure.

Pete

"John Smith" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

"Mark Jones" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Quoted message said:

A narrow light weight rim might not be able to accomodate the larger
hole required for a Shrader valve.

Very true. I do not think that the rims on my Trek 1200 could
handle a Schrader valve. The hole would be getting real close
to the edge of the rim.

When I acquired my current bicycle it had Schrader sized holes in the rim
but had presta valves with an adaptor to enable them to fill the full

valve

Quoted message said:

hole inserted in the rim. Shrug. I would have had schrader's inserted,
but my LBS was out of stock of tubes in that size.

kind of the worst of both worlds.

My Trek 7700 hybrid that I picked up tonight also has Presta valves.
This bike rides a lot smoother than my 1200, but the 1200 seems
to be a little faster on city streets. The 7700 will be used a lot on
multi-use trails where I never take the 1200.