Programming Cycle Computer

noeleoreid

Can anybody tell me an accurate way of measuring my wheel circumference to programme my cycle computer.

I have tried it once by placing the wheel so that the valve is face down towards the ground, then marked with a pen the point where it meets the ground. .. Then, I rolled the wheel one full rotation until again the valve was face down towards the ground and remarked this point. From here I measured the distance between the two marked points in mm as my computer programmes in mm. I arrived at a measurement of 2100 mm.

Now, another point to add to this.. I had the computer fitted to the bike in a cycle store (but not programmed there) but from reading up on how to fit them to the bike, they seem to have fitted it correctly. Its not wireless. So the sensor is about half way down the fork and the magnet on the spoke is about 1 mm away from the sensor, so that much seems right I THINK!

I have an Giant OCR 4 compact if it helps. Dunno what year of manufacturer.

So any methods on how to measure this would be appreciated?? The more accurate the better??

Cheers
Noel

blorg

2100mm sounds about right. If you spin the wheel and it increments, you are good to go.

8kvscdpglqnyr4

Measure the height of the wheel - I used a t-square from my Leaving Cert tech drawing like the one below. Then multiply the height by PI (3.14159).

Captain Havoc

read the side of the tyre wall