presta valves

mary said:

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" <[email hidden]> wrote in message
news:jG04k.788$ul.37@trndny08...

Quoted message said:

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

mary said:

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

mary said:

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.

mary said:

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.

Quoted message said:

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

mark said:

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.

"Guy Anderson, Sr." <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

mary said:

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

Bob said:

mary said:

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

Pat said:

Quoted message said:

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

Quoted message said:

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....

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

Quoted message said:

mark said:

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.

Pat wrote, On 6/12/2008 10:23 PM:

Quoted message said:

Quoted message said:

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)

Quoted message said:

Quoted message said:

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.

Quoted message said:

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

mary said:

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

Burr said:

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

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

Quoted message said:

Burr said:

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

Burr who? said:

Quoted message said:

Quoted message said:

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.

Quoted message said:

Quoted message said:

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).

Quoted message said:

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

Pat said:

Quoted message said:

Quoted message said:

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.

Quoted message said:

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.