Rim Size for Sigma 1600 Computer?

I think I answered my own question, looked at the tires and they are 40-622,
which equates to the 700X40C Sigma setting.

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

Quoted message said:

I am trying to setup a sigma 1600 cycle computer.

My rims are araya 700C PX 45.

Looking in the Sigma manual it lists sizes 700x20C up to 700X40C.

Which is the appropriate setting for my rim?

Thanks

In article <[email hidden]>,

The Eye said:

I think I answered my own question, looked at the tires and they are 40-622,
which equates to the 700X40C Sigma setting.

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

Quoted message said:

I am trying to setup a sigma 1600 cycle computer.

My rims are araya 700C PX 45.

Looking in the Sigma manual it lists sizes 700x20C up to 700X40C.

Which is the appropriate setting for my rim?

That setting is an approximation. While that may be close enough for
your purposes, you can accurately measure the circumference and enter it
into the computer. Actual circumference will depend on the actual tire
used, the inflation pressure and the load on it.

Place a mark on a flat smooth surface, and place the valve on it. With
your usual weight on the bike, roll forward several revolutions and
measure the distance. Divide by the number of revolutions and there's
your circumference.

--
Ted Bennett
Portland, OR

Ted covers it in a nutshell, for more detail visit Sheldon Brown's web
site.
Happy Holidays

On Sat, 25 Dec 2004 17:31:04 GMT, Ted <[email hidden]>

Quoted message said:

Place a mark on a flat smooth surface, and place the valve on it. With
your usual weight on the bike, roll forward several revolutions and
measure the distance. Divide by the number of revolutions and there's
your circumference.

For years I've just measured the OD of the wheel/tire (after changing
tire brands, for example), multiplied by pi, and entered that into my
cyclocomputers. This has always proven accurate to plus/minus one
percent.

jeverett3<AT>earthlink<DOT>net http://home.earthlink.net/~jeverett3