Schwinn Computer

Quoted post said:

Originally posted by Rider2004
Getting desperate here...I have the newest model of this worthy unit from Target and had to replace the battery but I have lost the manual for it.

Does anyone know what that four-digit number is (it defaults to 2124)??? I suspect it refers to the wheel diameter.

From a typical 42 year-old schmuck...

😕 in California (& TGIF!!!)

Hey there,
Didn't see your post until now. Yes that is the default setting usually used for 700x25c. (diameter in mm)

I believe that your Schwinn unit is sold also as the Topeak 130. They have a manual online at:

http://www.topeak.com/2004/manuals/pdfs/Comp%20130/comp_130.pdf

They have some guidelines for the wheel diameter, or you can fine tune it (I usually end up with 2110 for 700x23c with my pressure & weight)

A Newbie here - I have been looking high and low for the setting on my Giant OCR2 - 700x25c and the link you gave had it - YEAH!

However, what do the numbers MEAN? the 700 is... what? and the 25c is.... what?

I ask because bad me, didn't pay attention at bike shop when the sold me most recent tube. First time, got a 700x28/32c (27 x 1.25) this last time got a 700x18/23c (27x 1.0)

NEITHER are 700x25. BOTH seem close.

I've only changed 1 tire in my life, and when I got the tube in there it crinkled a little bit but seemed fine. So was that a little BIG? And this other small?

Like an idiot, I forgot to ask, and they're closed until Monday and, I've got another darn flat! (too much glass on the streets aroundhere)

Thanks in advance

The numbers represent the nominal diameter and width of the tire in mm. Actual measurements will rarely be exactly those figures. The cyclocomputer setting on those models (e.g. 2124) is suppossed to represent the actual rotational circumference of the tire with weight on it. (raw speed(dist./min)=rpm(number of times magnet passes sensor/minute) x rotational distance(circumference)) You can measure off a length and roll the bike while sitting on it, to get a more precise settting, but I have usually found tweaking by longer accurately measured highway miles to be better.

You probably should be using a tube with a 700/18x25c, 700/19x26c or something similar that overlaps the 700x25c size.
The 700/18x23c will probably work in a pinch, but will be a bit stretched for its intended purpose and may be more prone to flats. Like you said a 28/32 is going to be difficult to fit properly without creasing.

You shouldn't have any problem finding 700/18x25c as they seem to be the predominate small size 700c road tubes.