Sigma BC issue

[AlexisWolf]

Help and advice please. Despite inputting wheel size and checking many times my Sigma BC600 is way over estimating distance and speed. I measured the distance from valve stem for 1 revolution at 2085mm and checked it. Only today I went on a short road ride that I know is 7 miles but the read out was 10.91!!. Anyone got any ideas? It just doesn't make sense. Thank you.

 

[Racing roadkill]

Help and advice please. Despite inputting wheel size and checking many times my Sigma BC600 is way over estimating distance and speed. I measured the distance from valve stem for 1 revolution at 2085mm and checked it. Only today I went on a short road ride that I know is 7 miles but the read out was 10.91!!. Anyone got any ideas? It just doesn't make sense. Thank you.

Put a marker down on the road when the valve is at 12 o clock. Roll forward until the valve is back at 12 o clock and measure that distance, it will take into account the tyre size ( at the pressure you’re riding it at).

 

[AlexisWolf]

Put a marker down on the road when the valve is at 12 o clock. Roll forward until the valve is back at 12 o clock and measure that distance, it will take into account the tyre size ( at the pressure you’re riding it at).

I did just that (except I used 6 o'clock to 6 o'clock as my marker) It seems nuts, the Sigma has been brilliant until I had to change the battery and it then needed wheel size data re-inputting.

 

[Ajax Bay]

I went on a short road ride that I know is 7 miles but the read out was 10.91!!. Anyone got any ideas?

Well you "know" it's 7 miles. Might the distance of this ride be 10.91 . . . . . kilometres? (6.8 miles)
What size are the tyres?
23-622 700x23 2096
25-622 700x25 2105
28-622 700x28 2136
https://www.cateye.com/data/resources/Tire_size_chart_ENG_151106.pdf

 

[AlexisWolf]

Yes, I think that's dawned on me!...but I have it set on MPH..... I'll have to consult the instruction manual if I can find it on the net.....

 

[Ajax Bay]

If you have the computer set to MPH then you need to input the imperial 'interpretation' of the wheel size. If you think 2085mm is the accurate circumference of the wheel and fitted, inflated tyre then try "1296".
1296 is 2085 divided by 1.609 (the number of km in a mile).

 

[AlexisWolf]

I think you've got it there Ajax. I've had the BC so long now I forgot what the instructions are. I don't remember doing this before though, I just expected the 'computer' to do the math for me....quite the fool I am!
I'm at work now so I'll try this this evening and see what happens.
Thanks for your help..