Bigger Tires: Do I Need To Calibrate Speedometer

[cisc21]

If I am going to larger rims and tires do I need to re-calibrate for the speedometer?

 

[colek]

It depends on if the new tire diameter is bigger or smaller than the original tire. Example - the AV factory Goodyear HP is 265/70/17 on a Z-66 the tire diameter is 32". If you upgraded to a 265/50/20 the diameter becomes 30.5" the same as a 295/45/20. With this example you would need to recalibrate the speedometer. In most circumstances the speedo will need to be recalibrated, the good news is it's not that hard.

 

[conwayavalancher]

It depends on if the new tire diameter is bigger or smaller than the original tire. ?Example - the AV factory Goodyear HP is 265/70/17 on a Z-66 the tire diameter is 32". ?If you upgraded to a 265/50/20 the diameter becomes 30.5" the same as a 295/45/20. ?With this example you would need to recalibrate the speedometer. ?In most circumstances the speedo will need to be recalibrated, the good news is it's not that hard. ?

Edward...I've noticed a pattern here....YOU ALWAYS BEAT ME TO THE PUNCH Anyways...yeah...what Edward said...lol Good job Edward

 

[colonelmotox]

Thanks for the great explanation. I always just mentally adjust with those electric speed signs rather than recalibrating figuring I am going 4-5 miles per hr faster than the reading on the speedometer. If the speed light says 35 then I am doing right at 40. This new explanation you provided now tells me 'why' I would have to recalibrate.

 

[colek]

Edward...I've noticed a pattern here....YOU ALWAYS BEAT ME TO THE PUNCH ?Anyways...yeah...what Edward said...lol ?Good job Edward

Keep trying young grasshopper....