Speedo correct??

[h2100]

Hey all,
I upgraded my wheels from 18“ to 20“ on my 2019 Tahoe. I now have this discrepancy between the needle and digital display. Actually I don't know that it wasn't there before because I upgraded the wheels pretty quick after I bought the truck. I understood that there would be maybe a 1 mile an hour difference at about 80 miles an hour but this looks like 3 miles per hour difference at 65. Which one do you think is correct? I'd rather just guess it with you all then with John Law when he stops me to chat!

 

[Doubeleive]

Hey all,
I upgraded my wheels from 18“ to 20“ on my 2019 Tahoe. I now have this discrepancy between the needle and digital display. Actually I don't know that it wasn't there before because I upgraded the wheels pretty quick after I bought the truck. I understood that there would be maybe a 1 mile an hour difference at about 80 miles an hour but this looks like 3 miles per hour difference at 65. Which one do you think is correct? I'd rather just guess it with you all then with John Law when he stops me to chat!

View attachment 258737

normally you see a 2-3mph difference when changing the tire size to 20", about 5mph if you went to 22"
some canned tuners will have a option to correct it, but it sounds like a tune is not your forte'

 

[Big Mama]

Did the tire size (height) change as well or did you go with a shorter tire?

 

[h2100]

normally you see a 2-3mph difference when changing the tire size to 20", about 5mph if you went to 22"
some canned tuners will have a option to correct it, but it sounds like a tune is not your forte'

Which one is correct. The dial or the digital display?

 

[h2100]

Did the tire size (height) change as well or did you go with a shorter tire?

Yes bigger overall diameter. Two sizes I think. I can't check it now cuz I am actually driving

 

[Doubeleive]

Whichever one that is showing faster, your speed will 2-3mph more than what it was with 18's, if in doubt check with a gps
my Denali was originally built with 18's and the selling dealer put 20's on it, my speedo is off 2-3 mph due to this, no big deal no cop is going to get you for 2-3mph over the limit.

 

[Doubeleive]

if I get on the freeway and set my cruise control for 70mph and have my gps going the gps will bounce between 72-73mph

 

[h2100]

if I get on the freeway and set my cruise control for 70mph and have my gps going the gps will bounce between 72-73mph

Yes it appears the digital display is accurate and the needle is a little high

 

[swathdiver]

if I get on the freeway and set my cruise control for 70mph and have my gps going the gps will bounce between 72-73mph

Since when do you drive at 70 on the freeway? Since NEVER! LOL

 

[Doubeleive]

Since when do you drive at 70 on the freeway? Since NEVER! LOL

I did "once" to check the speedo, lol
about the same amount of times that I have used the cruise control