Recalibrate odometer and speedometer after changing tire

[m7han]

I changed my 18 in OEM wheels/tires to 20 in wheels/tires. I am assuming my odometer and speedometer would not be accurate. Has anyone tried to recalibrate the odometer/speedometer after changing tires? Also, would the miscalibration of the odometer/speedometer result in "fake" range loss after changing to larger tires? Thanks.

Sponsored

 

[billyp]

I can't imagine the difference between and 18 and 20" tire is going to be more than a couple mi/hr. May be nothing if you're running lower profile tires on the 20" rims -- overall diameter may be identical.

On my Jeep I went from 30-33" diameter tires and speedometer is ~5mph slow now.

You can verify with a speedo app on your phone to see around how much it's off.

 

[heisnuts]

You are not going to be able to recalibrate the gauges as you described. When changing your wheels from 18 to 20 inch the tire sidewall needs to be reduced so the outside circumference is the same. If your 18" tires were 225/60/18 the 20" should be something like 245/45/20.

 

[HuntingPudel]

I guess the first question is to what size did you change your tires? If the outside diameter (OD) is the same or very nearly the same as your original tires’ OD, you have nothing to worry about. If it’s drastically different, then there are things that either need to be done mentally so that you are sure you are not speeding, or possibly through software. ??

There are recalibration tools available in some states that the 4x4 guys use. I’ve read that ForScan can also correct the car for tire OD. ?‍?

 

[m7han]

You are not going to be able to recalibrate the gauges as you described. When changing your wheels from 18 to 20 inch the tire sidewall needs to be reduced so the outside circumference is the same. If your 18" tires were 225/60/18 the 20" should be something like 245/45/20.

Thanks for your advice. I changed from 225/60/18 to 245/45/20, so the difference should be minimum.

 

[m7han]

I guess the first question is to what size did you change your tires? If the outside diameter (OD) is the same or very nearly the same as your original tires’ OD, you have nothing to worry about. If it’s drastically different, then there are things that either need to be done mentally so that you are sure you are not speeding, or possibly through software. ??

There are recalibration tools available in some states that the 4x4 guys use. I’ve read that ForScan can also correct the car for tire OD. ?‍?

Thanks for your advice. I changed from 225/60/18 to 245/45/20, so the OD should be pretty close.

 

[Earplug]

Just use a tire comparison calculator. In your case the new tires are -
.3% smaller in circumference 89.9" vs 90.1"
@ 20 mph actual will be 20.1 mph
@ 70 mph actual will be 70.2 mph
205 vs 704 Revolutions per Mile

Source - Tire Size Comparison

 

[Polar]

Thanks for your advice. I changed from 225/60/18 to 245/45/20, so the difference should be minimum.

They are almost the exact same size - you’re good!

What tires and wheels did you get??!!
-I too made the exact same change on my Select, love the extra traction!!

 

[m7han]

They are almost the exact same size - you’re good!

What tires and wheels did you get??!!
-I too made the exact same change on my Select, love the extra traction!!

I got Fast Wheel FC 04 and Michelin CrossClimate 2:

Sponsored