but you have to follow the rollout cuz that is the most accurate

I know, but maybe I didn't have the stem perfectly at a right angle to the ground. The best way I see is to mark the tire with chalk, white out or paint and that would be perfect, but quite the hassle. I don't see how it could improve on taking the diameter of the tire X3.1416.

Not sure about your calculator. 82.25 x 25.4 = 2089 (fwiw)

Tire pressure should be normal before doing the rollout check.

ok, nobody mentioned the tire flattening when you're on the bike. Surely that decreases the circumference. Got 82" with a 700x23c which is 2083.

What degree of accuracy do you have in measuring the diameter of the tire? If you just take the mfg word for the tire diameter, I suspect you will not even be close.

It's quite simple and very little hassle to do this right. Make sure your tire pressure is up. Put a healthy dot of paint or whiteout on the tire. Get on the bike and roll (in a straight line) at least one complete revolution so that you have at least two points to measure. Take the measurement in inches and multiply by 25.4 and you have the number to plug into your unit. Using 26 x 3.14159 is only close in the horseshoe/hand grenade department. But if that's close enough for you, so be it.

btw, the locking mechanism on this computer is garbage. Just pushing a button can cause it to come loose and hit the ground. It has a release lever that is supposed to let it slide out, but there is no need for this lever because it slides out so easily on its own.

You need to slide it all the way until you hear a click, then it should be firmly locked. I never had a problem with mine at all. I have my wireless come off its mount multiple times when I hit a bump. Whenever it hit the pavement, it loses all data and you have to reprogram again. So much for wireless for me. JMO.

also you can improve the tension of the clip by gently bending it upward without the computer in it. then the plastic arm will have a little more tension. and yes, push the unit back until you hear a click. it may not be bullet proof but it stays on.

back to the Schwinn. I cleared the DST and MAX on my last ride no problem, but when I cleared it for this morniong's commute it didn't stick ... weird. so now I have to subtract my last STATs to get the morning's STATs :(

On the same topic of cheap and simple computers, has anyone seen one that also offers cadence, as well as basic speed and distance?

Also, if you are going to use the roll-out method for wheel circumference, repeat the measurement 3-5 times and then take an average of all the measurements. This will be more accurate. You'll be surprised at how different each measurement is.

I have 2 of the $10 Schwinn and they work fine. I have one on my commuter & the other on my touring bike

it helps if you remember to attach the computer! I was 2 miles into my ride home when I looked down for an update and realized it was still in my pocket DOI!

Genius! I bent the tab upward and now its solid as a rock (well, better at least).

:thumb: