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How critical is road bike tire pressure max?



 
 
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  #21  
Old April 19th 18, 02:18 AM posted to rec.bicycles.tech
Andre Jute[_2_]
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Posts: 8,626
Default How critical is road bike tire pressure max?

On Wednesday, April 18, 2018 at 7:13:18 PM UTC+1, AMuzi wrote:
On 4/18/2018 12:57 PM, Earls61 wrote:
Is max pressure related to tpi?


Yes, and other factors (such as tpi of which material):

http://file.scirp.org/pdf/WJET_2016051313584674.pdf

There are 100+ years of study in that area

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971


It is worth noting explicitly that cheaper tyres with lower TPI need to be inflated to higher pressures to work as well as better tyres with higher TPI.

AJ
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  #22  
Old April 19th 18, 04:44 AM posted to rec.bicycles.tech
Frank Krygowski[_4_]
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Posts: 5,851
Default How critical is road bike tire pressure max?

On 4/18/2018 5:54 PM, Joerg wrote:
On 2018-04-18 14:42, Frank Krygowski wrote:
On 4/18/2018 5:01 PM, Joerg wrote:
On 2018-04-18 13:15, Duane wrote:

Yeah, I'm mostly used to hearing people ask how low they can go and
still avoid snakebites.* I guess those gnarly country trails "out
there"
are better than our paved roads here in Quebec.


In California they just put a cone on there or slop some asphalt
slurry in there, roll the truck across it a few times and call it a day.

https://s.hdnux.com/photos/62/33/32/.../3/920x920.jpg

"Your tax Dollars at work"


Is there a place where they do more than that? I haven't found one yet.


Texas, Nevada, Utah and Arizona are among states which have a road
system that on average is by far in better shape. Florida also left a
good impression every time I drove there.


You're answering a different question than the one that was asked. I
expect southern states to have better roads than my northern one, simply
because it's the freeze-thaw cycle that causes most potholes.

Do the states you listed have a different pothole repair method? That
was the question.

In my area, some roads are owned and repaired by the state, some by the
county, some by the township, some by the city. All use the same pothole
repair technique. The same is true in the neighboring state (which is
just five miles away).

I don't doubt that better methods exist, but the priority here seems to
be filling in the greatest number of holes in the shortest amount of
time, because the crews can't keep up as it is. In fact, maybe two
months ago, potholes that suddenly appeared in a local interstate
highway were so bad that multiple cars had blowouts. One woman parked
her car on the interstate in an attempt to help a stranded motorist and
was killed by another car.

Given those possibilities, officials don't want to try for perfection. I
once heard that one California town (perhaps Palo Alto??) had an
ordinance requiring that pothole patches be no more than 1/4" above the
normal road surface. That is impossible here, in any practical sense.

Around here they don't bother rolling the truck across the asphalt they
shovel in. They leave it loose, figuring that traffic will eventually
flatten it a bit.


Union stranglehold like here?


State, county, township or city/village? It varies. Our village street
workers are not unionized. I know a couple of them well, and have worked
with them on certain projects. They're good guys.

--
- Frank Krygowski
  #23  
Old April 19th 18, 06:06 PM posted to rec.bicycles.tech
Joerg[_2_]
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Posts: 5,107
Default How critical is road bike tire pressure max?

On 2018-04-18 18:14, AMuzi wrote:
On 4/18/2018 6:53 PM, Joerg wrote:
On 2018-04-18 16:15, jbeattie wrote:


[...]

The first thing you could do is figure out which
government deserves
all your carping. Start with looking at local transportation
funding. Get on the CSD Board. Make Cameron Park Great
Again! SMS
has at least made himself part of the "deep state" of
Cupertino.


Road conditions are mostly in the hands of DOT. Last year
they increased car taxes and gas taxes to "fix the roads".
Noticeable results so far? Zero.


If you look at subsidiarity as Jay suggests I think you'll find your
county and township road departments maintain and plow and patch all the
not-incorporated roadways with various funding sources.

In some counties west of here, you can clearly see the township lines by
the road conditions after a snow while traveling on the same road.


Even in our residential neighborhood the trucks and crews are often from
the state DOT.

Those guys must have somehow lost the capability to operate a steam
roller because much of the newly laid asphalt is so wobbly that I try to
ride on the remnants of the old road surface if some is left open.

--
Regards, Joerg

http://www.analogconsultants.com/
  #24  
Old April 19th 18, 06:45 PM posted to rec.bicycles.tech
Joerg[_2_]
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Posts: 5,107
Default How critical is road bike tire pressure max?

On 2018-04-18 18:16, Andre Jute wrote:
On Wednesday, April 18, 2018 at 6:02:49 PM UTC+1, Joerg wrote:
Just received some 25mm Vee Rubber road tires and it says 7bar
100psi max on the side. That's a bit low for my taste.

The Zafiro I have on there now says 100psi min and 130psi max which
is more up my alley.

By how much can a low max rating be exceeded? I like 100-115psi on
my road bike in back. On the front I won't exceed the max because
a blow-out would be nasty and that carries less weight anyhow.

-- Regards, Joerg

http://www.analogconsultants.com/


Is this some new California fad, riding offroad on narrow rubber?
Whatever for? BTW, I have no problem with low- or zero-tread tyres
because I ride mainly on tarmac, even in the narrowest lanes, but
surely a mudplugger wants considerable mechanical grip.


No fad but road bikes out here must cope with road sections that are
either gravel or dirt. Part of life.


There's a good reason not to blow up tyres over the max
recommendation: It can get pretty nasty and expensive when
overinflated tyres blow the rim apart. It is well worth reading Andy
Blance, the designer of Sheldon's beloved Thorn bike, on tyre
inflation: see page 36 at
http://www.sjscycles.com/thornpdf/th...a_brochure.pdf


It's a 30+ MB file and their server seems to be on an old dial-up line.


I was a convert to comfortable suspension and inflation regimes
already in my motor-racing days, and achieved the same results the
same way in cycling: see
http://thorncyclesforum.co.uk/index....16360#msg16360
(which is an extended version of a reply I first made on RBT to a
query by Pete Cresswell) and read on in the ensuing very
well-informed engineering discussion about ways of determining the
optimum tyre inflation.

In fact, there are all kinds of really good reasons for inflating
bicycle tyres to the lowest you can get away with short of snake
bites.



Right, and then you get a pinch flat or snake bite which is often
unfixable in the field. All it takes is one pothole. No thanks.


... I run my bike on 60mm Big Apple Liteskins inflated to 2 bar,
which is about 29psi and I had two flats in 8500km, by which time the
tyres were perhaps half worn. One of those was a snakebite when I hit
a pothole at the bottom of a hill at 51kph when the tyres at the end
of the month-long reinflation interval were probably down to 1.5 bar,
and the other was a nail I picked up by going into an industrial
building site to ask the workmen to show me their battery-operated
angle grinder (which is a threat to locked bikes).

AJ Both flats happened right after I announced that in 10 years on
Big Apples I never had a flat...


The turf here is "slightly" different from the UK.

I found that riding close to max allowed pressure serve me best. On the
MTB it also results in less side wall damage.

--
Regards, Joerg

http://www.analogconsultants.com/
  #25  
Old April 19th 18, 09:39 PM posted to rec.bicycles.tech
SMS
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Posts: 8,194
Default How critical is road bike tire pressure max?

On 4/18/2018 4:15 PM, jbeattie wrote:

snip

You complain about all the idiots in government, yet you do nothing. The first thing you could do is figure out which government deserves all your carping. Start with looking at local transportation funding. Get on the CSD Board. Make Cameron Park Great Again! SMS has at least made himself part of the "deep state" of Cupertino.


I can help him with his campaign. Joerg should run. An engineer is a
good person to have on a City Council. The pay is incredible. I estimate
I am making at least 22 cents per hour. Attorneys are also very good to
have. So I think Jay needs to take the plunge as well.
  #26  
Old April 19th 18, 09:42 PM posted to rec.bicycles.tech
SMS
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Posts: 8,194
Default How critical is road bike tire pressure max?

On 4/18/2018 4:15 PM, jbeattie wrote:

You complain about all the idiots in government, yet you do nothing. The first thing you could do is figure out which government deserves all your carping. Start with looking at local transportation funding. Get on the CSD Board. Make Cameron Park Great Again!


I guess we'll have to address him as the Honorable Joerg Schulze-Clewing.
  #27  
Old April 19th 18, 11:16 PM posted to rec.bicycles.tech
Joerg[_2_]
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Posts: 5,107
Default How critical is road bike tire pressure max?

On 2018-04-19 13:39, sms wrote:
On 4/18/2018 4:15 PM, jbeattie wrote:

snip

You complain about all the idiots in government, yet you do nothing.
The first thing you could do is figure out which government deserves
all your carping. Start with looking at local transportation
funding. Get on the CSD Board. Make Cameron Park Great Again! SMS
has at least made himself part of the "deep state" of Cupertino.


I can help him with his campaign. Joerg should run. An engineer is a
good person to have on a City Council. The pay is incredible. I estimate
I am making at least 22 cents per hour. Attorneys are also very good to
have. So I think Jay needs to take the plunge as well.



I know someone who did this. It ended in utter frustration.

--
Regards, Joerg

http://www.analogconsultants.com/
  #28  
Old April 20th 18, 05:55 AM posted to rec.bicycles.tech
Tim McNamara
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Posts: 6,795
Default How critical is road bike tire pressure max?

On Wed, 18 Apr 2018 13:02:12 -0700, Joerg
wrote:
On 2018-04-18 12:51, jbeattie wrote:


snip

Also, why would Joerg want a HP 25mm tire in super-gnarlyville? With
all the ad hoc trail riding and massive loads, he should have a 32mm
tire minimum. And not a Zaffiro, which are flat-prone.



So far so good. The ride on the Zafiro is a bit more bone-rattling
than others but no flats. Part of my usual road bike valley route is
gravel and old Lincoln highway which looks like a concrete runway
after a bombing raid. I've got thick tubes plus liners in there though
which affords me the option to ride just about any tire.


... If his bike won't
accommodate a tire of that size, may that's a reminder that he's
riding the wrong bike.


I might get by with 28mm but only with absolutely zero wobble and that
ain't gonna happen on any of my bikes.


You're riding the wrong bikes, then. From what you describe about (a)
your riding environments and (b) the unending litany of mechanical
failures and other travails... you're riding the wrong bikes.

You should be on bikes accommodating tires 40+ mm wide. This will
sharply reduce your flat tire problems, your ride discomfort problems,
many of your premature service failure problems, etc.

Underbiking is one thing. You're doing something else.
  #29  
Old April 20th 18, 04:01 PM posted to rec.bicycles.tech
Joerg[_2_]
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Posts: 5,107
Default How critical is road bike tire pressure max?

On 2018-04-19 21:55, Tim McNamara wrote:
On Wed, 18 Apr 2018 13:02:12 -0700, Joerg
wrote:
On 2018-04-18 12:51, jbeattie wrote:



[...]


... If his bike won't
accommodate a tire of that size, may that's a reminder that he's
riding the wrong bike.


I might get by with 28mm but only with absolutely zero wobble and that
ain't gonna happen on any of my bikes.


You're riding the wrong bikes, then. From what you describe about (a)
your riding environments and (b) the unending litany of mechanical
failures and other travails... you're riding the wrong bikes.

You should be on bikes accommodating tires 40+ mm wide. This will
sharply reduce your flat tire problems, your ride discomfort problems,
many of your premature service failure problems, etc.


That's why I operate two bikes and one of them is this:

http://www.analogconsultants.com/ng/bike/Muddy4.JPG


Underbiking is one thing. You're doing something else.


Nah, just picking the bike I want for a ride. The MTB is slower and for
errand rides the road bike is more favorable. It's just that the trip is
often not 100% on paved surfaces.

--
Regards, Joerg

http://www.analogconsultants.com/
  #30  
Old April 20th 18, 06:25 PM posted to rec.bicycles.tech
JBeattie
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Posts: 3,061
Default How critical is road bike tire pressure max?

On Thursday, April 19, 2018 at 10:45:47 AM UTC-7, Joerg wrote:
On 2018-04-18 18:16, Andre Jute wrote:
On Wednesday, April 18, 2018 at 6:02:49 PM UTC+1, Joerg wrote:
Just received some 25mm Vee Rubber road tires and it says 7bar
100psi max on the side. That's a bit low for my taste.

The Zafiro I have on there now says 100psi min and 130psi max which
is more up my alley.

By how much can a low max rating be exceeded? I like 100-115psi on
my road bike in back. On the front I won't exceed the max because
a blow-out would be nasty and that carries less weight anyhow.

-- Regards, Joerg

http://www.analogconsultants.com/


Is this some new California fad, riding offroad on narrow rubber?
Whatever for? BTW, I have no problem with low- or zero-tread tyres
because I ride mainly on tarmac, even in the narrowest lanes, but
surely a mudplugger wants considerable mechanical grip.


No fad but road bikes out here must cope with road sections that are
either gravel or dirt. Part of life.


There's a good reason not to blow up tyres over the max
recommendation: It can get pretty nasty and expensive when
overinflated tyres blow the rim apart. It is well worth reading Andy
Blance, the designer of Sheldon's beloved Thorn bike, on tyre
inflation: see page 36 at
http://www.sjscycles.com/thornpdf/th...a_brochure.pdf


It's a 30+ MB file and their server seems to be on an old dial-up line.


I was a convert to comfortable suspension and inflation regimes
already in my motor-racing days, and achieved the same results the
same way in cycling: see
http://thorncyclesforum.co.uk/index....16360#msg16360
(which is an extended version of a reply I first made on RBT to a
query by Pete Cresswell) and read on in the ensuing very
well-informed engineering discussion about ways of determining the
optimum tyre inflation.

In fact, there are all kinds of really good reasons for inflating
bicycle tyres to the lowest you can get away with short of snake
bites.



Right, and then you get a pinch flat or snake bite which is often
unfixable in the field. All it takes is one pothole. No thanks.


Do you not carry a tube? You can squeeze one in next to the heart-lung machine, rope, winch and iron rail segment used for pounding in chain-pins with found fence nails. There should be room in your pannier somewhere.

-- Jay Beattie.

 




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