Proper Tire Inflation

Roger Zoul said:

I've read a bit on this on Sheldon Brown's site, however, I'm looking for a more precise answer, if
possible.

My road bike tires say that max inflation is 130 psi. Okay, before my last 25 mile ride, I inflated
my front tire to 130 psi, since I wanted to roll easy. So I do the ride okay, get the home & put
the bike up w/ no problems. Next time I go for it, the front tire is flat. Get the tube off to find
it split several inches along the inside seem, so it appears to me that this was due to over
inflation. Was it? And if so, could I have avoided this by inflating to 125 psi, instead of 130
psi? It was a clear & sunny day, so there was no need to have less air in the tire. How close to
max can one go, in general? Maybe a had a slightly bumb tube?

Your answer is in your own text. The tire's max inflation is 130, and it survived the 130psi just
fine. The tube, however did not fare so well. Sounds like you had a bad tube. It is interesting
though that you say it was "split several inches along the inside seem". Is that a several inch long
split, or in several inches from the valve, or something else? A several inch split would tell me it
blew while inside - after the ride. Otherwise, you would have been riding on the rim.

Dan Brussee wrote:
:: On Mon, 8 Dec 2003 15:00:18 -0500, "Roger Zoul" <[email hidden]> wrote:
::
::: I've read a bit on this on Sheldon Brown's site, however, I'm looking for a more precise answer,
::: if possible.
:::
::: My road bike tires say that max inflation is 130 psi. Okay, before my last 25 mile ride, I
::: inflated my front tire to 130 psi, since I wanted to roll easy. So I do the ride okay, get the
::: home & put the bike up w/ no problems. Next time I go for it, the front tire is flat. Get the
::: tube off to find it split several inches along the inside seem, so it appears to me that this
::: was due to over inflation. Was it? And if so, could I have avoided this by inflating to 125 psi,
::: instead of 130 psi? It was a clear & sunny day, so there was no need to have less air in the
::: tire. How close to max can one go, in general? Maybe a had a slightly bumb tube?
::
:: Your answer is in your own text. The tire's max inflation is 130, and it survived the 130psi just
:: fine. The tube, however did not fare so well. Sounds like you had a bad tube. It is interesting
:: though that you say it was "split several inches along the inside seem". Is that a several inch
:: long split, or in several inches from the valve, or something else? A several inch split would
:: tell me it blew while inside - after the ride. Otherwise, you would have been riding on the rim.

Thanks. The tube had a split along the inside seem that was several inches long. I would not expect
a puncture to produce a split like that, on the inner radius of the tube. Also, I don't think I was
riding on the rim -- that I have learned to notice 🙂

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

Quoted message said:

I've read a bit on this on Sheldon Brown's site, however, I'm looking for

a

Quoted message said:

more precise answer, if possible.

My road bike tires say that max inflation is 130 psi. Okay, before my

last

Quoted message said:

25 mile ride, I inflated my front tire to 130 psi, since I wanted to roll easy. So I do the ride
okay, get the home & put the bike up w/ no

problems.

Quoted message said:

Next time I go for it, the front tire is flat. Get the tube off to find

it

Quoted message said:

split several inches along the inside seem, so it appears to me that this was due to over
inflation. Was it? And if so, could I have avoided this by inflating to 125 psi, instead of 130
psi? It was a clear & sunny day, so there was no need to have less air in the tire. How close to
max can one go, in general? Maybe a had a slightly bumb tube?

Thanks.

It's quite common for people to pump their tires right to the max psi or even slightly beyond. I
don't recommend going beyond, but I know it's pretty commonly done by folks like triathletes and
that who believe they're reducing rolling resistance.

Sounds to me like you had a bumb tube, but I'd make sure your rim tape is covering all the spoke
holes on the rim and that there aren't any exposed edges that could create a hole.

One last thing. High psi isn't good for all wheels. Some of the fancy, low-spoke count, light weight
wheels can develop cracks at the spoke holes if you keep the tire pressure too high.

Bob C.

Roger Zoul said:

I've read a bit on this on Sheldon Brown's site, however, I'm looking for a more precise answer,
if possible.

Quoted message said:

My road bike tires say that max inflation is 130 psi. Okay, before my last 25 mile ride, I
inflated my front tire to 130 psi, since I wanted to roll easy. So I do the ride okay, get the
home & put the bike up w/ no problems. Next time I go for it, the front tire is flat. Get the tube
off to find it split several inches along the inside seem, so it appears to me that this was due
to over inflation. Was it? And if so, could I have avoided this by inflating to 125 psi, instead
of 130 psi? It was a clear & sunny day, so there was no need to have less air in the tire. How
close to max can one go, in general? Maybe a had a slightly bum tube?

Tubes cannot split open in the tire from high pressure. Your tire blew off the rim while you weren't
there or you would have heard it. You should probably run tires at 120psi or less, and don't expect
to descend steep braking hills at that pressure either.

draco.acs.uci.edu8b.4.htmlOpen ↗

This is not new.

Jobst Brandt [email hidden]

In article <[email hidden]>, [email hidden] says...

Quoted message said:

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

Quoted message said:

I've read a bit on this on Sheldon Brown's site, however, I'm looking for

a

Quoted message said:

more precise answer, if possible.

My road bike tires say that max inflation is 130 psi. Okay, before my

last

Quoted message said:

25 mile ride, I inflated my front tire to 130 psi, since I wanted to roll easy. So I do the ride
okay, get the home & put the bike up w/ no

problems.

Quoted message said:

Next time I go for it, the front tire is flat. Get the tube off to find

it

Quoted message said:

split several inches along the inside seem, so it appears to me that this was due to over
inflation. Was it? And if so, could I have avoided this by inflating to 125 psi, instead of 130
psi? It was a clear & sunny day, so there was no need to have less air in the tire. How close to
max can one go, in general? Maybe a had a slightly bumb tube?

Thanks.

It's quite common for people to pump their tires right to the max psi or even slightly beyond. I
don't recommend going beyond, but I know it's pretty commonly done by folks like triathletes and
that who believe they're reducing rolling resistance.

Sounds to me like you had a bumb tube, but I'd make sure your rim tape is covering all the spoke
holes on the rim and that there aren't any exposed edges that could create a hole.

One last thing. High psi isn't good for all wheels. Some of the fancy, low-spoke count, light
weight wheels can develop cracks at the spoke holes if you keep the tire pressure too high.

How does that happen? I can see cracking from too-high spoke tension, but not from too-high
tire pressure.

--
Dave Kerber Fight spam: remove the ns_ from the return address before replying!

REAL programmers write self-modifying code.

Quoted message said:

Quoted message said:

One last thing. High psi isn't good for all wheels. Some of the fancy, low-spoke count, light
weight wheels can develop cracks at the spoke holes if you keep the tire pressure too high.

How does that happen? I can see cracking from too-high spoke tension, but not from too-high tire
pressure.

Mavic has a maximum recommended air pressure for their wheel/rims. It's buried somewhere on their
website and lower than you might think.

Chris Neary [email hidden]

"Science, freedom, beauty, adventure: what more could you ask of life? Bicycling combined all the
elements I loved" - Adapted from a quotation by Charles Lindbergh

psycholist wrote:
:: "Roger Zoul" <[email hidden]> wrote in message
:: "]news:[email hidden]...
::: I've read a bit on this on Sheldon Brown's site, however, I'm looking for a more precise answer,
::: if possible.
:::
::: My road bike tires say that max inflation is 130 psi. Okay, before my last 25 mile ride, I
::: inflated my front tire to 130 psi, since I wanted to roll easy. So I do the ride okay, get the
::: home & put the bike up w/ no problems. Next time I go for it, the front tire is flat. Get the
::: tube off to find it split several inches along the inside seem, so it appears to me that this
::: was due to over inflation. Was it? And if so, could I have avoided this by inflating to 125 psi,
::: instead of 130 psi? It was a clear & sunny day, so there was no need to have less air in the
::: tire. How close to max can one go, in general? Maybe a had a slightly bumb tube?
:::
::: Thanks.
:::
::
:: It's quite common for people to pump their tires right to the max
:: psi or even slightly beyond. I don't recommend going beyond, but I know it's pretty commonly done
:: by folks like triathletes and that who believe they're reducing rolling resistance.
::
:: Sounds to me like you had a bumb tube, but I'd make sure your rim tape is covering all the spoke
:: holes on the rim and that there aren't any exposed edges that could create a hole.

I did check the rim tape covering the spoke holes...all seems fine there.

::
:: One last thing. High psi isn't good for all wheels. Some of the fancy, low-spoke count, light
:: weight wheels can develop cracks at the spoke holes if you keep the tire pressure too high.

Mine are by Specialized...those are low-spoke count wheels, too. However, the tires are 700 x 26, so
those aren't as lightweight as others, I'd think.

[email hidden] wrote:
:: Roger Zoul writes:
::
::: I've read a bit on this on Sheldon Brown's site, however, I'm looking for a more precise answer,
::: if possible.
::
::: My road bike tires say that max inflation is 130 psi. Okay, before my last 25 mile ride, I
::: inflated my front tire to 130 psi, since I wanted to roll easy. So I do the ride okay, get the
::: home & put the bike up w/ no problems. Next time I go for it, the front tire is flat. Get the
::: tube off to find it split several inches along the inside seem, so it appears to me that this
::: was due to over inflation. Was it? And if so, could I have avoided this by inflating to 125 psi,
::: instead of 130 psi? It was a clear & sunny day, so there was no need to have less air in the
::: tire. How close to max can one go, in general? Maybe a had a slightly bum tube?
::
:: Tubes cannot split open in the tire from high pressure. Your tire blew off the rim while you
:: weren't there or you would have heard it. You should probably run tires at 120psi or less, and
:: don't expect to descend steep braking hills at that pressure either.

You know....when I first went to get the bike and noticed the flat, the tire was off the rim! I
remember wondering how it could have come off like that, rather than just going flat. BTW, on the
day of my ride it was extremely windy, and I'm a heavy guy. Maybe there was some rim heating.
::
:: draco.acs.uci.edu8b.4.htmlOpen ↗
::
:: This is not new.

I see. Thanks.

In article <[email hidden]>, [email hidden] says...

Quoted message said:

Quoted message said:

Quoted message said:

One last thing. High psi isn't good for all wheels. Some of the fancy, low-spoke count, light
weight wheels can develop cracks at the spoke holes if you keep the tire pressure too high.

How does that happen? I can see cracking from too-high spoke tension, but not from too-high tire
pressure.

Mavic has a maximum recommended air pressure for their wheel/rims. It's buried somewhere on their
website and lower than you might think.

I understand why a rim might have a limit on pressure (at least for clinchers), but this would seem
to be a bead/rim sidewall issue, not a spoke hole issue.

--
Dave Kerber Fight spam: remove the ns_ from the return address before replying!

REAL programmers write self-modifying code.

"Roger Zoul"

Quoted message said:

the tires are 700 x 26, so those aren't as lightweight as others, I'd think.

700 x 26 with a max pressure rating of 130 psi? That sounds very unusual. Normally, max pressure
ratings increase as the tire width decreases.

What brand of tire is this?

Art Harris

Art Harris wrote:
:: "Roger Zoul"
::: the tires are 700 x 26, so those aren't as lightweight as others, I'd think.
::
:: 700 x 26 with a max pressure rating of 130 psi? That sounds very unusual. Normally, max pressure
:: ratings increase as the tire width decreases.
::
:: What brand of tire is this?

FRONT TIRE Specialized New Turbo Pro, 700 x 26c, kevlar bead

REAR TIRE Specialized New Turbo Pro, 700 x 26c, kevlar bead

On Tue, 9 Dec 2003 07:39:57 -0500, David Kerber

ns_dkerber@ns_ids.net said:

In article <[email hidden]>, [email hidden] says...

Quoted message said:

Quoted message said:

> One last thing. High psi isn't good for all wheels. Some of the fancy, low-spoke count, light
> weight wheels can develop cracks at the spoke holes if you keep the tire pressure too high.

How does that happen? I can see cracking from too-high spoke tension, but not from too-high tire
pressure.

Mavic has a maximum recommended air pressure for their wheel/rims. It's buried somewhere on their
website and lower than you might think.

I understand why a rim might have a limit on pressure (at least for clinchers), but this would seem
to be a bead/rim sidewall issue, not a spoke hole issue.

I imagine that the pressure on the bead would result in some folding pressure along the inside of
the rim; and the spoke holes, right on center, would be the weak point.
--
Rick Onanian

Rick Onanian said:

Quoted message said:

Quoted message said:

>> One last thing. High psi isn't good for all wheels. Some of the fancy, low-spoke count, light
>> weight wheels can develop cracks at the spoke holes if you keep the tire pressure too high.

Quoted message said:

Quoted message said:

Quoted message said:

> How does that happen? I can see cracking from too-high spoke tension, but not from too-high
> tire pressure.

Quoted message said:

Quoted message said:

Quoted message said:

Mavic has a maximum recommended air pressure for their wheel/rims. It's buried somewhere on
their website and lower than you might think.

Quoted message said:

Quoted message said:

I understand why a rim might have a limit on pressure (at least for clinchers), but this would
seem to be a bead/rim sidewall issue, not a spoke hole issue.

Quoted message said:

I imagine that the pressure on the bead would result in some folding pressure along the inside of
the rim; and the spoke holes, right on center, would be the weak point.

Since tires blow off at about 130psi, there is no reason for a rim not to sustain such pressures. I
believe the reason for giving a limit is to prevent people from suing them for not warning that
their rims will not retain tires over a certain pressure. The rim can take it, but can the rider,
when the tire blows off?

Jobst Brandt [email hidden]

Quoted message said:

Since tires blow off at about 130psi, there is no reason for a rim not to sustain such pressures. I
believe the reason for giving a limit is to prevent people from suing them for not warning that
their rims will not retain tires over a certain pressure. The rim can take it, but can the rider,
when the tire blows off?

I never have seen a properly inflated tire blow off an MA-2 or a CR-18.

I believe it could happen but I think you would have to have overinflated to a degree and be braking
hard in a descent to see it.

I've seen rims get very hot and steam come off them in hard braking, or at least water vapor. I
never saw a tire blow off.

Unless you count the most recent TDF. That was a tubular rolling off the rim due to the glue
melting, IMHO.

--

_______________________ALL AMIGA IN MY MIND_______________________ ------------------"Buddy Holly,
the Texas Elvis"------------------
__________306.350.357.38>>[email hidden]__________

Eric S. Sande said:

Quoted message said:

Since tires blow off at about 130psi, there is no reason for a rim not to sustain such pressures.
I believe the reason for giving a limit is to prevent people from suing them for not warning that
their rims will not retain tires over a certain pressure. The rim can take it, but can the rider,
when the tire blows off?

Quoted message said:

I never have seen a properly inflated tire blow off an MA-2 or a CR-18.

Quoted message said:

I believe it could happen but I think you would have to have over-inflated to a degree and be
braking hard in a descent to see it.

I assure you that it has been don descending on MA-2 rims with IRC 700x25 tires pumped to 100 psi. I
have done it and so have people with whom I ride. This was after more than 100 miles of hilly
riding. We know how a poorly mounted tire feels. This was simple overheating.

Quoted message said:

I've seen rims get very hot and steam come off them in hard braking, or at least water vapor. I
never saw a tire blow off.

Tandem folks can tell you a lot about that if they tour in the mountains. I have testified in suits
against the bicycle industry by such folks.

Quoted message said:

Unless you count the most recent TDF. That was a tubular rolling off the rim due to the glue
melting, IMHO.

That and other reasons.

Jobst Brandt [email hidden]

Quoted message said:

I have testified in suits against the bicycle industry by such folks.

Pehaps you could elaborate. Many of the newer people don't know your crdentials.

--

_______________________ALL AMIGA IN MY MIND_______________________ ------------------"Buddy Holly,
the Texas Elvis"------------------
__________306.350.357.38>>[email hidden]__________

In article <[email hidden]>, [email hidden] says...

Quoted message said:

David Kerber ns_dkerber@ns_ids.net said:

In article <[email hidden]>, [email hidden] says...

Quoted message said:

>> One last thing. High psi isn't good for all wheels. Some of the fancy, low-spoke count,
>> light weight wheels can develop cracks at the spoke holes if you keep the tire pressure too
>> high.
>
>How does that happen? I can see cracking from too-high spoke tension, but not from too-high
>tire pressure.

Mavic has a maximum recommended air pressure for their wheel/rims. It's buried somewhere on
their website and lower than you might think.

I understand why a rim might have a limit on pressure (at least for clinchers), but this would
seem to be a bead/rim sidewall issue, not a spoke hole issue.

I imagine that the pressure on the bead would result in some folding pressure along the inside of
the rim; and the spoke holes, right on center, would be the weak point.

True; I hadn't thought of that, but in that case, *higher* spoke counts would be worse than *low*
ones (except of course that low spoke count wheels are typically of lighter construction as well).

--
Dave Kerber Fight spam: remove the ns_ from the return address before replying!

REAL programmers write self-modifying code.

In article <[email hidden]>, [email hidden] says...

...

Quoted message said:

Quoted message said:

I imagine that the pressure on the bead would result in some folding pressure along the inside
of the rim; and the spoke holes, right on center, would be the weak point.

Since tires blow off at about 130psi, there is no reason for a rim not to sustain such pressures.
I believe the reason for giving a limit is to prevent people from suing them for not warning that
their rims will not retain tires over a certain pressure. The rim can take it, but can the rider,
when the tire blows off?

Do you mean to say that there is no way that any clinchers can handle above 130 psi?

--
Dave Kerber Fight spam: remove the ns_ from the return address before replying!

REAL programmers write self-modifying code.

I found out after complete exasperation that Continental Avenues, .26x1.3 can be inflated WAY WAY
over their max. (I was using Conti tubes as well)

The avenues are horrendously hard to seat well since the bead slips off the rim to the inside and
doesn't completely climb back on on inflation. Usually it works fairly well if you smear a little
dishwashing liquid on the inside of the trouble spot and over inflate a little bit but this time the
tyre stubbornly refused to climb back onto the rim. The sidewall rating is 80PSI max and I inflated
them to 120PSI before the damn thing went "TWANG" and seated smoothly.

Ofcourse when it went "TWANG" at last, I nearly wet myself, thinking for a split second it had
exploded :P

I didn't attempt to ride with the over inflated tyre though 🙂

Anine

"Roger Zoul" <[email hidden]> wrote in message news:<[email hidden]-
berlin.de>...

Quoted message said:

I've read a bit on this on Sheldon Brown's site, however, I'm looking for a more precise answer,
if possible.

My road bike tires say that max inflation is 130 psi. Okay, before my last 25 mile ride, I
inflated my front tire to 130 psi, since I wanted to roll easy. So I do the ride okay, get the
home & put the bike up w/ no problems. Next time I go for it, the front tire is flat. Get the tube
off to find it split several inches along the inside seem, so it appears to me that this was due
to over inflation. Was it? And if so, could I have avoided this by inflating to 125 psi, instead
of 130 psi? It was a clear & sunny day, so there was no need to have less air in the tire. How
close to max can one go, in general? Maybe a had a slightly bumb tube?

Thanks.