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Gear ratio + speedometer calibration

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Moderator: mikel

Post Sat Feb 04, 2017 1:29 pm

Posts: 2
2005 Ram 1500 4x4 5.7
Trinity version 1r13k with dcx_gas
Switched to 35" tires. I do believe i have stock gear ration since i didnt changed it, which would be 3.55
According to GPS, my actual speed is 10kmh over what my speedometer is showing.
I tried setting up my new tire size in quick ajust. I tried both options available which is setting up by sidewall, or by tire height. Both options wont calibrate my speedometer right, it will always be 7-10kmh difference. I tried to trick it out by selecting tire sizes smaller than my actual 35's, but still won get it right on (i did manage to calibrate it @ ~5kmh difference)

Some will probably say that 5kmh isnt much of a big deal...true..but i do think there must be a possibility to have it calibrated right on dot.
There seems to be missing a Gear Ratio selection option. The tuner calibrates the speedometer according to what value of gear ratio ? Does it uses the stock value written in the PCM ?

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