Skorpion Vapor (or other bike type) Speedo Setting

[droy]

I've been running a Vapor Tach/speedo on my Sport since last fall. I'm currently running a tire diameter setting of 1809 mm (110/70 series BT45 tire). I've never checked the speedo to an actual mile/GPS or other means of checking speed. It dosent appear to be too far off - no recent speeding tickets! Anybody out there have a good tire diameter setting thats been confirmed for a simular set-up??

Thanks in advance.

Doug in NJ

[billr]

I haven't run a Vapor, but I have set-up numerous bicycle speedos that use the same type calibration.
Same issues with different tire brands and set-ups.
Here's what I do to get the correct number:
Roll the bike until the front tire valve stem is at the bottom and make a chalk mark on the floor of the garage (or mark the tire and floor at the same time).
Sit on the bike and roll it forward for 1 full revolution of the tire (valve stem at the bottom) and make a second mark.
Measure the distance, convert to millimeters and enter that number into the computer.

Hope this is what you were looking for.
Bill

[droy]

Bill,

Thanks - thats what I did to come up with the 1809 mm. Hoping someone can confirm this number based on "on road" GPS or mile marker check.

[billr]

, can't help much, then.

I had to fine-tune a couple of the bicycle speedos.
Rode a measured mile (markers) and adjusted the circumference number til it read 1 mile.
Took a few tries, but I got a good work-out
Bill

[rodge70]

set mine to 1870,used two revs of wheel then divide by two to get an average and assuming sat nav is accurate then it's spot on,draw back being it probably reads very accurate mileage which i supose the standard one reads less than that

[DAVID THOMPSON]

in work zones here we have a radar sign that shows speed
my traveller shows 55mph on radar sign when speedo says 59

Beg a gps from someone those tickets a lot of places cost big money plus points
that get you into a driving class--
with me and driving a school bus it can cost me my job
even if the speeding is in my off time and on my bike
dave