Speedometer show wrong speed, after tire-change to 315 75 r16

[TM1008]

Hello everybody

I need some help.

On my M1008 I have now mounted 315 75 r16 tires and now the speedometer is no longer showing the correct speed.

On NP208 is installed a pinion with 44 teeth, color gray.
On the case are the numbers 40/41/42/43.

I would like to order from TCI Auto a suitable pinion (i found some at Summit Racing), but I do not know which one to take.

I assume that nothing was changed on the car.
When I bought it, there were 285 75 r16 tires installed.
Before changing to the 315 I had the original tires mounted, 235 85 r16.

maybe someone has an idea or a solution


thanks in advance...
Greetings from Germany

 

[Drock]

From what I can tell it looks like a 42 tooth driven gear. http://www.tciauto.com/tc/speedometer-gear-calculator/