The 4-digit number that has to be entered for the wheel size (circumference) in mm. Due to not having listed all wheel sizes on the market, we would like to give the following guidelines.
1. Measure the wheel circumference
2. Find more information on the homepage of the tire manufacturer.
Due to changes of the tire pressure the most exact method to identify the circumference is to measure it. Please find a short instruction in the following.
Measuring the wheel circumference:
1. Mark a spot (start position) on the floor (using a tape or a chalk line).
2. Place the front wheel with the valve being exactly over the start position.
3. Roll out the front wheel until the valve is in the same position as it was in the start position. Mark the position of the valve on the floor.
4. Measure the distance in between the two marks. The difference in mm corresponds with the circumference that has to be entered into the computer.