Gear ratio change, tone ring question.

[MC]

We just changed our tour bus from 4.10 to 3.54 and it is a D-70 with a tone ring. The computer seemed to have compensated for the gear change on the speedo. Is this possible or are we just thinking it? We clocked it using a chase vehicle and it confirmed the speedometer to be correct. Did the computer in fact compensate for the gear ratio change? I thought they needed to be brought in for that....

[Jrod-13]

no, the reason it works fine is because the speedo runs off the tone ring, which is still turning the same speed as it was before.;

[Schmozilla]

The tone ring is on the ring gear which spins at the same speed as the wheel... gear ratio makes no diffrence for this typ of speed indication. Tire size however will effect it.

[MC]

Thats what I thought, thanks for the input guys!