I'm about to callibrate my speedo using a cycle computer with the sensor attatched to offside rear wheel.
Do I need to have both wheels off the ground or do I need to chock one of them to get the correct reading?
Speedo pickup is from the gearbox.

Help please

John

If you only have one wheel rotating, it will rotate twice the speed as normal.

Thankyou Ninja.
Getting myself confused here. been a long day.

Cheers
John