Does 2MPH really make that big of a difference

[jeffpaff]

My stock tires are LT275/65 R18 I am looking for something a little larger to fill the wheel well and I am going up to LT275/70 R18 based on my looking around the web now when the speedo says I am doing 60 I will really be doing 62. For shift points and ABS does 2MPH matter enough for me to put in a TruSpeed?
Thanks!

[20046.0]

I'm off 10-13km, never touched a thing..

[07OUTLAW]

No, you'll be fine

[jeffpaff]

Thanks guys, just paranoid!

[redbandit98]

ford speedo is off anyways. I have autoenginuity and have played around a bunch with tire sizes trying to get my speedo right on. Im sort of OCD. Anyways my truck has 34" tires. To get the speedo to read dead nuts on with a GPS, I have to input a 31" tire. When I input the correct size, the speedo reads about 3mph fast. (If Im actually going 60, speedo will read 63). I have just accepted the fact that its off and left it.

[The_Pats_Fan]

Stock speedo on mine was 2-3mph below actual, anyway.... I would assume you should be fine. If you are going with significantly larger tires however, yes you do need to adjust the ABS. Primarily for emergency stopping of slippery weather. (Mud/rain/ice/snow) Having the wrong size tires and ABS can throw you out of control in slippery conditions emergency stops.