Tire / Tyre pressure

In article ER4Ka.11339$3d.6242@sccrnsc02 said:

I read on Sheldon Brown's web site that many people don't pay lot of attention to max tire
pressure (this is my paraphrase). Does this mean that I can inflate my 100psi tires to 120 psi?

Usually. At your own risk. ;-)

However, there is may be good reason not to do this. Large section tires (>28 mm) are usually made
with 66 TPI casings and are not necessarily able to deal with the high pressure. With the larger
diameter tire casing, tension on the cords in the fabric is higher than in smaller tires at the same
pressure. I think I have that right, I've never quite been able to tigure out how that works and am
just parroting here.

Also, that 20 psi means a harsher ride and may not result in lower rolling resistance.

Tim McNamara <[email hidden]> wrote in message
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Quoted message said:

However, there is may be good reason not to do this. Large section tires (>28 mm) are usually made
with 66 TPI casings and are not necessarily able to deal with the high pressure. With the larger
diameter tire casing, tension on the cords in the fabric is higher than in smaller tires at the
same pressure. I think I have that right, I've never quite been able to tigure out how that works
and am just parroting here.

It should be quite easy to figure out, if you think of tire as a cylinder and cut it in the
middle. Now you have two rectangles on which the pressure applies trying to push these two
half-cylinders appart. The force on these rectangles is pressure * area. If you have a wider tire,
the area of the rectangles will be larger and thus the force will be higher. This force has to
carried by the fabric.

Joakim

"[email hidden]" <[email hidden]> wrote in message news:<ER4Ka.11339$3d.6242@sccrnsc02>...

Quoted message said:

I read on Sheldon Brown's web site that many people don't pay lot of attention to max tire
pressure (this is my paraphrase). Does this mean that I can inflate my 100psi tires to 120 psi?

Since I got my first hook-bead rim I have been running 120 psi in my road bike tires, even though
the ratings on the tires is 100 or 110. I've ridden 30K miles in the last four years. I'm not
sure how many miles before 1999 I've been running that pressure because I didn't keep good
records back then.

Tom

Quoted message said:

I read on Sheldon Brown's web site that many people don't pay lot of attention to max tire
pressure (this is my paraphrase). Does this mean that I can inflate my 100psi tires to 120 psi?

Are you questioning Sheldon? I think the information on his web site speaks for itself.

sheldonbrown.comtires.htmlOpen ↗

Art Harris

Thanks for the reply. Can you feel the difference in better rolling resistance?

thanks,

Tom

"Thomas Reynolds" <[email hidden]> wrote in message
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Quoted message said:

"[email hidden]" <[email hidden]> wrote in message

news:<ER4Ka.11339$3d.6242@sccrnsc02>...

Quoted message said:

Quoted message said:

I read on Sheldon Brown's web site that many people don't pay lot of attention to max tire
pressure (this is my paraphrase). Does this mean

that

Quoted message said:

Quoted message said:

I can inflate my 100psi tires to 120 psi?

Since I got my first hook-bead rim I have been running 120 psi in my road bike tires, even though
the ratings on the tires is 100 or 110. I've ridden 30K miles in the last four years. I'm not
sure how many miles before 1999 I've been running that pressure because I didn't keep good
records back then.

Tom

Where did I "question", I need a follow up. I'm glad you think it speaks for itself. But i didn't
get the full picture. Do you have an answer or are you just being bellicose?

Tom

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

Quoted message said:

Quoted message said:

I read on Sheldon Brown's web site that many people don't pay lot of attention to max tire
pressure (this is my paraphrase). Does this mean

that

Quoted message said:

Quoted message said:

I can inflate my 100psi tires to 120 psi?

Are you questioning Sheldon? I think the information on his web site speaks for itself.

sheldonbrown.comtires.htmlOpen ↗

Art Harris

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

Quoted message said:

Thanks for the reply. Can you feel the difference in better rolling resistance?

Tom, I used to run my 100psi tires at 120, but honestly, it was just too painful and didn't feel any
faster. The 80-100 range is what I stick to.

It also depends on your local road/path quality. Mine is usually [censored], with sand strewn everywhere.
I lose the front end a lot but MTBing has helped with that.

--
Phil, Squid-in-Training

Quoted post said:

Where did I "question", I need a follow up. I'm glad you think it speaks for itself. But i didn't
get the full picture. Do you have an answer or are you just being bellicose?

Well, of course you CAN pump your "100 psi" tires up to 120 psi. Whether you should or not is
another question. Unfortunately, you provided no information on which to base a recommendation
(i.e., your weight, tire width, etc.).

Art Harris

Thanks Phil. What size tires do you use? What is your weight?

Thanks,

Tom

"Phil, Squid-in-Training" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

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

Quoted message said:

Thanks for the reply. Can you feel the difference in better rolling resistance?

Tom, I used to run my 100psi tires at 120, but honestly, it was just too painful and didn't feel
any faster. The 80-100 range is what I stick to.

It also depends on your local road/path quality. Mine is usually [censored],

with

Quoted message said:

sand strewn everywhere. I lose the front end a lot but MTBing has helped with that.

--
Phil, Squid-in-Training

"Trying" <[email hidden]> wrote in message news:2vDKa.22956$Bg.13461@rwcrnsc54...

Quoted message said:

Thanks Phil. What size tires do you use? What is your weight?

700x25 Continental somethings, 140lbs. Steel frame.

--
Phil, Squid-in-Training

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Quoted message said:

Thanks for the reply. Can you feel the difference in better rolling resistance?

thanks,

Tom

Yes I can. That is why I do it. I also don't feel that the ride is excessively harsh.