presta valves

[mary]

Is it just me or do tubes with presta valves have to be filled up more
often? It seems like once a week I have to top off the air in the tubes.
Just wondering. Oh and before you ask, yes I make sure the valve is closed
all of the way after filling.

 

[Bob]

On Jun 11, 10:25 pm, "mary" <[email protected]> wrote:
> Is it just me or do tubes with presta valves have to be filled up more
> often?  It seems like once a week I have to top off the air in the tubes..
> Just wondering. Oh and before you ask, yes I make sure the valve is closed
> all of the way after filling.

The valve is the weakest link in any tube but it isn't the only place
air escapes. You lose pressure through the tube wall itself as well so
no matter how tightly you seat the valve you're still going to need to
get out the pump periodically. That said, needing to pump up the tires
once a week seems pretty much usual to me.

Regards,
Bob Hunt

 

[Burr]

"mary" <[email protected]> wrote in message
news:jG04k.788$ul.37@trndny08...
> Is it just me or do tubes with presta valves have to be filled up more
> often? It seems like once a week I have to top off the air in the tubes.
> Just wondering. Oh and before you ask, yes I make sure the valve is closed
> all of the way after filling.

Mary,
I run 120psi so I have top off about once a week. I get three 20 or 30
mile rides a week. But the rides have nothing to do with, the tube walls
leak not the valve.

If you are real light you can run less air but the more air the easer it
is to turn the crakes but the more you bounce. The tour riders run
160-190psi.

Hope it helps.

Burr

 

[mark]

mary wrote:
> Is it just me or do tubes with presta valves have to be filled up more
> often? It seems like once a week I have to top off the air in the
> tubes. Just wondering. Oh and before you ask, yes I make sure the valve
> is closed all of the way after filling.
Narrow, high pressure tires need reinflating more often than wide, low
pressure tires. Thickness of the tube probably has an effect, as would
the quality of the valve. FWIW, I top off my road bike's tires (700x23)
before every ride, but I will go a month at a time without reinflating
my touring bike's tires (26 x 1.75"). Both have Presta valves.

mark

 

[catzz66]

mary wrote:
> Is it just me or do tubes with presta valves have to be filled up more
> often? It seems like once a week I have to top off the air in the
> tubes. Just wondering. Oh and before you ask, yes I make sure the valve
> is closed all of the way after filling.

Rather than take my chances, I top my tires off before every ride and
ride nearly every day. I know full well that I could skip a day or two,
but I would rather go through my routine than to ever have another pinch
flat.

 

[Guy Anderson, Sr.]

On Thu, 12 Jun 2008 03:25:03 GMT, "mary" <[email protected]> wrote:

>Is it just me or do tubes with presta valves have to be filled up more
>often? It seems like once a week I have to top off the air in the tubes.

As several others have said, your experience with tires losing
pressure is entirely normal. Butyl is the slightest bit porous, so
the pressure escapes through the tube, not the valve--unless the valve
is defective or damaged (not likely). Ultra-light latex tubes are
worse yet, losing as much as 30# overnight!

Furthermore, your pre-ride pump-up is the perfect time to safety-check
your wheels and tires: check for loose bearings by shaking the wheel
side-to-side; spin the wheels and look for out-of-true wobbles (use
brake pad as stationary reference point); iInspect the tread for cuts,
bulges, abrasions, any other anomalies.

 

[Pat]

>
> Furthermore, your pre-ride pump-up is the perfect time to safety-check
> your wheels and tires: check for loose bearings by shaking the wheel
> side-to-side; spin the wheels and look for out-of-true wobbles (use
> brake pad as stationary reference point); iInspect the tread for cuts,
> bulges, abrasions, any other anomalies.

I don't agree with you here; I think the best time to safety check the
wheels and tires is post-ride. After all, there you are in the pre-ride,
ready and dressed to go riding---and suddenly you see a slit in the side
wall. Inspect post-ride and you have time to get things fixed before the
next ride. I check my tires after a ride when I put the bike on the rack on
the back of my car. The bike is at eye level and it's a good time to do it.

Pat in TX

 

[Andrew Price]

On Thu, 12 Jun 2008 00:52:28 -0600, mark <[email protected]> wrote:

>Narrow, high pressure tires need reinflating more often than wide, low
>pressure tires. Thickness of the tube probably has an effect, as would
>the quality of the valve. FWIW, I top off my road bike's tires (700x23)
>before every ride, but I will go a month at a time without reinflating
>my touring bike's tires (26 x 1.75"). Both have Presta valves.

Also my experience - well, almost. I usually manage to do 2 to 3 days
(around 40km per day) between topping up my 700x23 road tyres (which I
run at 9 bar). The touring bike, with 700x40 tyres inflated to 4.5
bar, goes at least a month before needing a top up.

 

[Burr]

"Guy Anderson, Sr." <[email protected]> wrote in message
news:[email protected]...
> On Thu, 12 Jun 2008 03:25:03 GMT, "mary" <[email protected]> wrote:
>
>>Is it just me or do tubes with presta valves have to be filled up more
>>often? It seems like once a week I have to top off the air in the tubes.
>
> As several others have said, your experience with tires losing
> pressure is entirely normal. Butyl is the slightest bit porous, so
> the pressure escapes through the tube, not the valve--unless the valve
> is defective or damaged (not likely). Ultra-light latex tubes are
> worse yet, losing as much as 30# overnight!
>
> Furthermore, your pre-ride pump-up is the perfect time to safety-check
> your wheels and tires: check for loose bearings by shaking the wheel
> side-to-side; spin the wheels and look for out-of-true wobbles (use
> brake pad as stationary reference point); iInspect the tread for cuts,
> bulges, abrasions, any other anomalies.

Nice post Guy!

ALWAYS CHECK YOUR TIRES!

Burr

 

[ZBicyclist]

Bob wrote:
> On Jun 11, 10:25 pm, "mary" <[email protected]> wrote:
>> Is it just me or do tubes with presta valves have to be filled up
>> more often? It seems like once a week I have to top off the air
>> in
>> the tubes. Just wondering. Oh and before you ask, yes I make sure
>> the valve is closed all of the way after filling.
>
> The valve is the weakest link in any tube but it isn't the only
> place
> air escapes. You lose pressure through the tube wall itself as
> well so
> no matter how tightly you seat the valve you're still going to
> need to
> get out the pump periodically. That said, needing to pump up the
> tires
> once a week seems pretty much usual to me.
>
> Regards,
> Bob Hunt

Mary, in conjunction with getting rims that use presta valves, are
you now using tires that use higher pressure?

Switch to 2.5 inch 35 psi knobbies and you'll fill up with air only
once a summer

--
Mike Kruger
"When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl." -
Anonymous

 

[ZBicyclist]

Pat wrote:
>> Furthermore, your pre-ride pump-up is the perfect time to
>> safety-check your wheels and tires: check for loose bearings by
>> shaking the wheel side-to-side; spin the wheels and look for
>> out-of-true wobbles (use brake pad as stationary reference
>> point);
>> iInspect the tread for cuts, bulges, abrasions, any other
>> anomalies.
>
> I don't agree with you here; I think the best time to safety check
> the
> wheels and tires is post-ride. After all, there you are in the
> pre-ride, ready and dressed to go riding---and suddenly you see a
> slit in the side wall. Inspect post-ride and you have time to get
> things fixed before the next ride. I check my tires after a ride
> when
> I put the bike on the rack on the back of my car. The bike is at
> eye
> level and it's a good time to do it.

But you still have to do a pre-ride check, in case there's a slow
leak -- or, if you left the rack trunk open and there's a cat in it


--
Mike Kruger
"When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl." -
Anonymous

 

[Pat]

>
> But you still have to do a pre-ride check, in case there's a slow leak --
> or, if you left the rack trunk open and there's a cat in it
>
> --
> Mike Kruger

My pre-ride check consists of me squeezing the tire between thumb and
forefinger....

 

[mary]

"Andrew Price" <[email protected]> wrote in message
news:[email protected]...
> On Thu, 12 Jun 2008 00:52:28 -0600, mark <[email protected]> wrote:
>
>>Narrow, high pressure tires need reinflating more often than wide, low
>>pressure tires. Thickness of the tube probably has an effect, as would
>>the quality of the valve. FWIW, I top off my road bike's tires (700x23)
>>before every ride, but I will go a month at a time without reinflating
>>my touring bike's tires (26 x 1.75"). Both have Presta valves.
>
> Also my experience - well, almost. I usually manage to do 2 to 3 days
> (around 40km per day) between topping up my 700x23 road tyres (which I
> run at 9 bar). The touring bike, with 700x40 tyres inflated to 4.5
> bar, goes at least a month before needing a top up.

All of these responses have been very helpful. I ride everyday at least 20
miles a day.
I will stop worrying and just check them every day. Thanks.

 

[Paul O]

Pat wrote, On 6/12/2008 10:23 PM:
>> But you still have to do a pre-ride check, in case there's a slow leak --
>> or, if you left the rack trunk open and there's a cat in it
>>
>> --
>> Mike Kruger
>>
>
> My pre-ride check consists of me squeezing the tire between thumb and
> forefinger....
>
>
>
I do that too. But, I also like to give my wheels a spin and see if they
are running true and look for any bulges in the tires. It only takes a
few seconds.

--

Paul D Oosterhout
I work for SAIC (but I don't speak for SAIC)

 

[Pat]

>> My pre-ride check consists of me squeezing the tire between thumb and
>> forefinger....
>>
>>
> I do that too. But, I also like to give my wheels a spin and see if they
> are running true and look for any bulges in the tires. It only takes a few
> seconds.

> Paul D Oosterhout

Okay, that's good---but I am NOT going to check my tires' air pressure every
single dang day! That's being obsessive about it. So what if the air
pressure has gone down 2 psi? or even, gasp, 5 psi?

Pat in TX

 

[smokey]

On Jun 11, 8:25 pm, "mary" <[email protected]> wrote:
> Is it just me or do tubes with presta valves have to be filled up more
> often?  It seems like once a week I have to top off the air in the tubes..
> Just wondering. Oh and before you ask, yes I make sure the valve is closed
> all of the way after filling.

The tubes themselves leak a little air. Thinner, higher pressure tubes
will be worse about this. I've tried a lot of different brands of
tubes and lately have been using the Schwalbe standard tubes. They
seem to leak less air than the others and seldom need topping up.

Smokey

 

[Chalo]

"Burr" wrote:
>
> If you are real light you can run less air but the more air the easer it
> is to turn the crakes but the more you bounce. The tour riders run
> 160-190psi.

I'd be very, very surprised if even one rider in the entire
international road racing peloton used pressure that high. Track
racers on the velodrome are known to do so, but on the road the energy
lost to slamming and vibrating the rider can far exceed any reduction
in rolling resistance achieved by using very high tire pressure. Many
Tour de France riders still use sewup tires, one of whose major
advantages is the ability to run _lower_ pressures without pinch
flatting.

Chalo

 

[Burr]

"Chalo" <[email protected]> wrote in message
news:4a140380-341d-4ecb-908f-3b44299d8847@f36g2000hsa.googlegroups.com...
> "Burr" wrote:
>>
>> If you are real light you can run less air but the more air the easer
>> it
>> is to turn the crakes but the more you bounce. The tour riders run
>> 160-190psi.
>
> I'd be very, very surprised if even one rider in the entire
> international road racing peloton used pressure that high. Track
> racers on the velodrome are known to do so, but on the road the energy
> lost to slamming and vibrating the rider can far exceed any reduction
> in rolling resistance achieved by using very high tire pressure. Many
> Tour de France riders still use sewup tires, one of whose major
> advantages is the ability to run _lower_ pressures without pinch
> flatting.
>
> Chalo

I learned something. I "thought" I remembered reading about them running
very high pressure.

Burr

 

[[email protected]]

Burr who? wrote:

>>> If you are real light you can run less air but the more air the
>>> easer it is to turn the crakes but the more you bounce. The tour
>>> riders run 160-190psi.

>> I'd be very, very surprised if even one rider in the entire
>> international road racing peloton used pressure that high. Track
>> racers on the velodrome are known to do so, but on the road the
>> energy lost to slamming and vibrating the rider can far exceed any
>> reduction in rolling resistance achieved by using very high tire
>> pressure. Many Tour de France riders still use sewup tires, one of
>> whose major advantages is the ability to run _lower_ pressures
>> without pinch flatting.

Not true. The term "snake bite" pinch flat was coined over patching of
such flats in latex tube Clement tubulars. The term was important
because it was not generally known that a pinch flat causes two holes
(as pinching one's cheek with thumb and forefinger).

> I learned something. I "thought" I remembered reading about them
> running very high pressure.

Its easy to find all sorts of myth an lore about bicycle racers that
can "leap tall buildings in a single bound"

http://www.answerbag.com/q_view/110331

Men of steel whose tires are equally hard and fast. Drugs play no
role in any of that aura. Don't believe everything you hear about
bicycle racers methods and abilities.

Jobst Brandt

 

[catzz66]

Pat wrote:
>>>My pre-ride check consists of me squeezing the tire between thumb and
>>>forefinger....
>>>
>>>
>>
>>I do that too. But, I also like to give my wheels a spin and see if they
>>are running true and look for any bulges in the tires. It only takes a few
>>seconds.
>
>
>>Paul D Oosterhout
>
>
> Okay, that's good---but I am NOT going to check my tires' air pressure every
> single dang day! That's being obsessive about it. So what if the air
> pressure has gone down 2 psi? or even, gasp, 5 psi?
>
> Pat in TX
>
>

Of course, when you depress the presta stem, you are going to let out
some more air anyhow, but for me, topping the tires off doesn't take
long and the tires feel the same every day.