Originally Posted by Getaway_bus
I'm looking at a 2001 freightliner with a Thomas body. It has the 24 valve 5.9L cummins with a MT545. First I know that the 643 is better in many ways and often preferred. I'm not looking for that debate. I also understand that rear gears and tire size will affect speed ( dont know what the rear gear ratio is but the tires are 10R22.5) my question is what kind of speed can I expect? My dad just purchased the same bus but a year newer with the 643 and on the was home from indiana he was pushing 75mph on flat ground.
Without knowing your gear ratio no one will know what speed your bus can go except you if you floor it on a long road.
Year of bus makes no difference nor does horsepower. Its ALL gearing. You could have a bus that tops out at like 45 if its from a district that has 45 mph buses. I had one from Cleveland Texas that was limited to 50 in the ECU. That's another thing- it could be electronically limited even if it has highway gearing.
Too many variables make more of guess than "somewhere between 45 and 85".