I ordered a new speedometer gear earlier this year because my speedometer was reading 10 mph over the actual speed. I was thinking it had the incorrect number of teeth. Took the gear out tonight and it's the same one that I figured I needed. 27 inch wheel diameter, 323 gear. (P255/60 R15) It has a 32 tooth gear. Should I go to the 31?
Is it 10 MPH over at all speeds ? If so the speedo gauge maybe the problem not the gear .
For example if you are 6 mph out @ 60 & 10 MPH out at 100 then you are off by 10% so change the amount of teeth by 10%
It seems to be 10 mph across the board. At 55 on the speedometer, I'm actually doing 45. I checked it on my phone gps.
sssssssssso I would suspect the speedo head , it might just need cleaning & lube
To the OP...
While out on the road, use the mile markers to check your odometer. If your odometer is reading correctly, then your speedo gear is correct.
You would need to pull the gauges & remove the speedo from there it is not hard to clean it & lube the moving parts , you need a light oil like a sewing machine oil or a thin synthetic