larger tires and speedo correction...

[huckleberry668]

i'm thinking of upgrading my 4Runner's 265/70/16 to 265/70/17 tires & rims. it's 1" larger in diameter but will cause -2 mph of speedo error. how do i fix that?

thanks

 

[RonMAIDEN]

It's actually about 3% diff so it's only a 3mph diff at 100mph so anything around hwy speeds will be less than 2mph. I really don't think there's a fix and the speed diff is so minor it shouldn't be an issue.

 

[wolfgang]

Its my understanding that all this is a simple change to the programing of the engine computer --- unlike the old days of cable driven speedo which necessitated changing speed drive gears. I still suspect dealer will charge $100 to hook to computer and make the change.

 

[huckleberry668]

Ahhh... I see. thanks guys!