Speedometer questions.

[2020Telly]

I can say a inaccurate speedo can eat away at your warranty mileage faster over time if it reads faster than what your really going, which of course benefits the manufacture. Especially if you do a lot of highway driving at faster speeds.

Speedometer and Odometer measure differently. The Speedometer has tolerances as the speed reading is subject to change a little depending on your tire size and wear. While the odometer must reflect more accurately and is measured using a fixed unchanging point in the vehicle for accurate distance.

 

[TELLUFIED 3.8]

Speedometer and Odometer measure differently. The Speedometer has tolerances as the speed reading is subject to change a little depending on your tire size and wear. While the odometer must reflect more accurately and is measured using a fixed unchanging point in the vehicle for accurate distance.

I always assumed that if your Speedo was off, that it would affect your odometer. So if I Put bigger tires on a vehicle it would slow the speedometer down (less revolutions of the wheel) in turn slowing the odometer down. Same way as changing a rear end gear in a vehicle. Or vice versa, how else would a odometer get miles driven. This was old school so maybe things have changed on the newer vehicles.

 

[2020Telly]

I always assumed that if your Speedo was off, that it would affect your odometer. So if I Put bigger tires on a vehicle it would slow the speedometer down (less revolutions of the wheel) in turn slowing the odometer down. Same way as changing a rear end gear in a vehicle. Or vice versa, how else would a odometer get miles driven. This was old school so maybe things have changed on the newer vehicles.

Bigger tires will make the speedometer read slower. But my speedometer was faster by about 1.5mph. I got new tires that raised my height by about .8” and I’m a little closer to 1mph faster reading than what I’m actually going. As my tires age and the circumstances get smaller it will probably be off by more again. If the Telluride is like other odometers it will measure revolutions on some inside point of the wheel and multiply it by a constant probably based on some average OEM tire size. So I guess it’s possible that if you put very large tires on you will travel less distance than your odometer will read. But I think the readings are done differently and when you change tires it remains proportional.