Changing air pressure
Groups | Search | About
Login Password
Register Now! Lost Password?

General Motorcycle Group - All things motorcycle 

Page 1 of 4       1 2 3 > last >> Bookmark this page:  YahooMyWeb Yahoo!  Google Google  Windows Live Favorites Windows Live  del.icio.us del.icio.us  digg digg  Add to Netscape Netscape
Subject Author Date
Changing air pressure Konrad Viltersten 01-20-2008
If you were  Registered and logged in, you could reply and use other advanced thread options
Posted by Konrad Viltersten on January 20, 2008, 2:51 pm
I wonder if people do that before winter. The weather is
colder, so the air in the tires gets compressed but is it
really a problem? Should i pump more air into the tubes?

--
Regards
Konrad Viltersten
-----------------------



Posted by Beauregard T. Shagnasty on January 20, 2008, 3:40 pm
Konrad Viltersten wrote:

> I wonder if people do that before winter. The weather is colder, so
> the air in the tires gets compressed but is it really a problem?
> Should i pump more air into the tubes?

You have to exchange the summer or fall air, for winter air. It's very
important that you do this each season.

However, use the same amount of pressure as recommended by the
manufacturer. Winter air will be heavier.

--
-bts
-Motorcycles defy gravity; cars just suck

Posted by Timberwoof on January 20, 2008, 5:08 pm

> I wonder if people do that before winter. The weather is
> colder, so the air in the tires gets compressed

No, it doesn't. Remember the Perfect Gas Law:

Pv = nRT

Pressure times volume equals the number of molecules times a factor that
makes the units work out times the temperature in Kelvin or Rankin. So
as temperature decreases, the pressure or volume decreases. The air gets
denser, but it does not get more compressed: the pressure is not higher.

> but is it
> really a problem? Should i pump more air into the tubes?

Yes. Air is always leaking out. Check your tire pressures weekly and
keep the tires up to spec. The temperature change will take care of
itself.

--
Timberwoof <me at timberwoof dot com>
faq: http://www.timberwoof.com/motorcycle/faq.shtml
Ten Steps to Fascism: http://www.guardian.co.uk/usa/story/0,,2064157,00.html

Posted by David T. Ashley on January 21, 2008, 10:44 pm
>
>> I wonder if people do that before winter. The weather is
>> colder, so the air in the tires gets compressed
>
> No, it doesn't. Remember the Perfect Gas Law:
>
> Pv = nRT
>
> Pressure times volume equals the number of molecules times a factor that
> makes the units work out times the temperature in Kelvin or Rankin. So
> as temperature decreases, the pressure or volume decreases. The air gets
> denser, but it does not get more compressed: the pressure is not higher.

The pressure gets lower in Winter. If you take the equation and solve for
P, you get

P = (nRT)/v

Although there is some elasticity in a tire, it is safe to assume that v is
constant, as the tire is relatively constant compared to the gas (not like
balloon).

You can see that with fixed volume, as T goes down, P goes down as well.

--
David T. Ashley (dta@e3ft.com)
http://www.e3ft.com (Consulting Home Page)
http://www.dtashley.com (Personal Home Page)
http://gpl.e3ft.com (GPL Publications and Projects)



Posted by Ken Abrams on January 20, 2008, 5:37 pm


> The weather is
> colder, so the air in the tires gets compressed but is it
> really a problem? Should i pump more air into the tubes?
>

Although your wording isn't exactly correct, the answers are: Yes and Yes.

And then in the spring time, you may need to let some out.

This only applies, however, if you will be RIDING the bike.
If it is just parked, you don't need to screw with the tires...........until
it is time to ride.



Page 1 of 4       1 2 3 > last >>

Contact Us | Privacy Policy

XML SitemapXML Sitemap