Sierra speedometer not accurate

[Khalid Almehairi]

I have a gmc sierra 2014 single cab, recently i have replaced my gauge cluster running 265s r18 but after replacing my cluster i have noticed difference in gauge speed vs actual gps speed

 

gauge speed giving 125km/h and actual speed 129km/h, the car is performance custom tuned, how can i calibrate the speed without affecting the custom tune? Anyone with knowledge can help me with this?

[L86 All Terrain]

You can have the speedometer recalibrated at your local GM dealer. They should be able to do it without changing the tune, but if they cant you will have to contact your tuner to do it for you. 

[Taz56]

On 12/5/2019 at 8:20 AM, L86 All Terrain said:

You can have the speedometer recalibrated at your local GM dealer. They should be able to do it without changing the tune, but if they cant you will have to contact your tuner to do it for you. 

My dealer wanted 500.00 CAD to recalibrate my speedometer. They told me 300.00 for a part they had to order and 150.00 to do it (plus taxes). I went on-line and ordered the part myself and am currently waiting for it.