Speed-o off??

On my trip yesterday I noticed that maybe my speed-o may be off. Now I am going by my GPS with also has the MPH on it. Would the lift I did, plus wheels etc, etc change it by 5 MPH over?

Need to make adjustments if need by.....if you know what I mean.

 

Not so much the lift but the larger wheels and tires, yes. Usually, though, the speedo is under by 3+ mph. Mine was reading 57 at 60mph and with the 265/75/16's I have now it's dead on. Mine has been verified via GPS and police radar (buddy is a cop).

 

Stock was 265/65-17. Now their 265/70-17. Speedo was +3mph.Now it's +1mph.Per my scan guage.

 

I went up a tire size and now my speedo is exactly the same as my GPS.

 

I am running 285's so I don't know if this would matter. If I am running 65 on the speed-o, GPS states 69.
I will have to get a couple of readings of a few pace cars to see what it really is.

 

Yeah my 09 tacoma shows 60 when my GPS shows 57... I was hoping I was opposite so when I do get bigger tires, it will even out. But I posted the exact same thread and was told (and tested it too) that the ODO is dead on, and I can say with accuracy (at least from my GPS) that this is true. Hope that helps.

Rob

 

My 09 is about 2-3 mph off as well....shows 75-76 and scan gauge and GPS show 72-73 today on my trip. I figure when I replace tires I will go with 265's and even it out but thats down the road a bit.

 

Anyone using a speedo correction when going with bigger tires?

 

Friend of mine did it for his ford. He went from 33's to 44's so I think he was 12mph off or something. The shop charged like $30 or something. It wasn't that bad considering the speeding ticket he got the day before for doing 85 in a 55 was like $120. He thought he was going 71